Unraveling Organoboron/Nickel Ion-Pair Interactions via Benchtop-Stable Carbyl Iminopyridyl NiII Complexes for Olefin Polymerization

Unraveling Organoboron/Nickel Ion-Pair Interactions via Benchtop-Stable Carbyl Iminopyridyl NiII Complexes for Olefin Polymerization | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Unraveling Organoboron/Nickel Ion-Pair Interactions via Benchtop-Stable Carbyl Iminopyridyl Ni II Complexes for Olefin Polymerization Eva Harth, Hasaan Rauf, Yu-Sheng Liu, Surya Pratap Solanki, Eric Deydier, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-3773688/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract While current research on Ni-catalyzed olefin polymerization predominantly focuses on ligand design, ion-pair interactions remain largely unexplored. We report the development of air-stable carbyl iminopyridyl Ni II precatalysts to enable an investigation of inner- and outersphere Ni ion-pairs. The use of innersphere organoboron counterions allows the Ni complexes to access higher molecular weight homo/co-polymers and regulate the density and distribution of polyethylene branches. Moreover, implementing a phenyl group on the tether carbon functioned as a rotational barrier, producing higher molecular weight polymers compared to methylsubstituted analogs. A controlled incorporation of shortchain branches was achieved under high ethylene pressure, circumventing the need for elaborate ligand design, low monomer pressures, and the copolymerization with α-olefins. DFT calculations further elucidated the ion-pair interactions and controlled chain-walking mechanism. Here, we provide a new perspective to manipulate the iminopyridyl Ni II system leveraging both ion-pair interactions and ligand design to govern polyolefin molecular weights and microstructures. Physical sciences/Chemistry/Catalysis/Homogeneous catalysis Physical sciences/Chemistry/Polymer chemistry/Polymer synthesis Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 INTRODUCTION The success of polymeric materials is rooted in their versatility, high performance, and affordable production. 1–3 Among these materials, polyolefins continue to make up about half of the polymer production due to their exceptional chemical resistance and tunable material properties. 4 In general, the physical properties of polyolefins are directly related to their molecular weight (MW) and microstructure, which is highly dependent on the involved catalytic system. The development of the Brookhart-type catalysts launched the field of late-transition metal-catalyzed olefin polymerization. 5 These α-diimine Pd II and Ni II complexes are highly tolerant of polar monomers and provide control over polymer microstructure through their unique "chainwalking" mechanism. 6–8 The α-diimine Ni II systems are attractive due to their high catalytic activity and earth abundancy of Ni. Over the years, there has been a surge in the development of ligands aimed at the control of the polymer microstructure to influence material properties. However, effective microstructure control has required the use of increasingly complex ligands. 9–11 These polymerization systems rely not only on the transition metal complex but also on the cocatalyst used for activation. The ionic interaction between the metal complex and the counterion has been demonstrated to have a significant impact on the catalytic activity and polymer architecture in transition metalcatalyzed olefin polymerizations. 12,13 However, there are no available catalytic systems that allows for the investigation of inner- and outersphere counterion effects in [ N,N ]chelated Ni II complexes. Diimine Pd II complexes can be designed with a carbyl ligand to be activated by both organoaluminum and organoboron cocatalysts. However, diimine Ni II analogs require dihalide ligands for olefin polymerization, limiting activation to bifunctional organoaluminium cocatalysts such as methylaluminoxane (MAO), which functions through halide abstraction and metal alkylation for coordination polymerization. 12,14 Moreover, MAO limits the indepth study of the influence of ligand design and reaction conditions to tailor the microstructure of polymers, due to the limited understanding of the anionic macrostructure. 15 Conversely, cocatalysts other than organoaluminium result in a well-defined anionic species, enabling the investigation of the ionpair that governs the polymeric characteristics and properties. 16 However, these cocatalysts require an carbyl precursor as they activate only through halide abstraction. Unfortunately, carbyl diimine Ni II complexes are unstable due to the lability of the NiC bond, as the diimine ligand cannot form a stable complex under ambient conditions. Stable η 3 and η 5 coordinated cationic diimine Ni complexes have been reported; however, they require the use of organoaluminum cocatalysts for olefin polymerization. 17–20 To evaluate the impact of counterions on iminechelated Ni II complexes, it is therefore crucial to develop a robust carbyl Ni II precatalyst. Such an approach could pave the way for unprecedented control over the polymer microstructure and MW by shifting the focus from complex ligand design to the utilization of ion-pairs. Specifically, our aim was to create an alkyl- or arylfunctionalized Ni precatalyst that could be activated solely by a scavenger, without the need for an alkylation process to generate the cationic complex for olefin polymerization. These complexes would serve as an ideal system for a variety of activators, expanding beyond the limitation of organoaluminum cocatalysts. Thus, we selected iminopyridine complexes, with the [ N , N ]ligand backbone serving as a diimine analog and the pyridine moiety acting as a stronger σ donor to help stabilize the labile NiC bond. 21 However, in contrast to symmetric diimine ligands, the addition of axial steric bulk does not promote chain-propagation and produces low MW polyethylene (PE). 22–26 More importantly, air-stable iminopyridyl mesityl Ni II complexes have been successfully synthesized using straightforward approaches. However, these catalysts were only found effective for cross-coupling reactions. 27 In this contribution, we disclose the synthesis of a new class of benchtop, airstable iminopyridyl Ni II complexes, C1C8 , which feature an o tolyl ligand as the carbyl substituent. We investigate the significance and effect of the ionpair for ethylene polymerization, and its role in tailoring branching characteristics and density of the produced PE with respect to the reaction conditions. The complexes are designed with a focus on a rotational barrier provided by either a methyl or phenyl group on the carbon tether and the ortho substituents on the aryl imine. Various cocatalysts such as modifiedMAO, sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (NaBArF), and organoboranes were evaluated for ethylene polymerization. Furthermore, we demonstrate the use of B(C 6 F 5 ) 3 as the primary cocatalyst for carbyl Ni II iminopyridyl complexes, producing active complexes and yielding high MW PE ( M n > 100 kg mol − 1 ). Density functional theory (DFT) studies support the establishment of a reversible innersphere anion coordination with ClB(C 6 F 5 ) 3 − , which reduces the overall catalytic activity, but allows the production of higher MW polymers. Moreover, the activation of these complexes with B(C 6 F 5 ) 3 reveals that the substituent on the carbon tether greatly influences the polymer MWs through a rotational restriction of the ortho substituents on the N aryl moiety. The chain-walking behavior led to controlled branching densities and short-chain branching distributions, ranging from methyl to butyl, depending on the reaction temperature (0–80°C), producing polymers with diverse macrostructures. DFT studies support a proposed mechanistic pathway to elucidate the chain-walking mechanism that determines the controlled branching distribution at varying reaction temperatures. Complex C7 was used to evaluate the efficacy of the carbyl iminopyridyl Ni complexes for copolymerization with polar monomers. These carbyl Ni II iminopyridyl complexes are competitive catalysts in which not only the MW but also the branching characteristics can be tuned by cocatalysts and ligand design. In addition, a single catalyst can generate several types of PEs, such as high-density PE (HDPE), low-density PE (LDPE), elastomers, oligomeric waxes, and oils, with different branching densities without the need for copolymerization with α-olefins. This class of complexes is poised to open synthetic alternatives to produce high-performance polyolefins with defined and targeted microstructures, which is uncommon for a onecomplex/onemonomer catalytic system. RESULTS AND DISCUSSION Design and Development of Carbyl Iminopyridyl Nickel Catalysts The design of the Ni II iminopyridyl complexes focused on two aspects. First, the selection of an appropriate carbyl group and second, evaluating a rotational barrier provided by the substituent on the tether carbon between the two iminopyridine donor functions. We chose an o tolyl group as the carbyl substituent, as the aryl ligand has been found to produce benchtopstable bipyridine Ni II complexes. 21,28 We hypothesize that the steric bulk of the single N aryl moiety cannot sufficiently contribute to the effective blockage of the metal center to limit chain-transfer. The rotational barrier would restrict the N aryl moiety and its substituents in their mobility, providing more effective axial bulk to limit chain-transfer. The emphasis on the rotational barrier provided by the tether carbon atom was motivated by reports where sterically bulkier ortho substituents on the N aryl moiety produced lower MW PE. 22,23,26 Only with synthetically demanding half-sandwich ligands can high MW materials be produced. 24,25 This behavior contradicts the established trend reported in late-transition metal complexes where increasing the steric bulk around the metal center produced higher MW materials. In our previous work, we demonstrated that by introducing a “rotational barrier” via methyl substituents at the meta position on the ortho phenyl groups, the geometry of the complex was distorted to more effectively shield the metal center. 29 Therefore, we explore the effect of steric bulk on the tether carbon atom by introducing a phenyl group to serve as an analogous rotational barrier. A series of iminopyridine ligands ( L1L8 ) were synthesized (Fig. 1 ). Ligands L1 , L3 , L5 , and L7 feature a methyl group on the tether carbon atom and a varied steric bulk on the N aryl moiety, ranging from isopropyl to benzosuberyl groups. Whereas L2 , L4 , L6 , and L8 have a phenyl group on the tether carbon. Ligands L1L5 were prepared according to reported procedures, using a one-step condensation reaction of the aniline with the targeted ketone, and were isolated in high yields (Fig. 1 ). 23,30–33 The more rigid and bulkier L6L8 were designed to further investigate the rotational barrier with sterically bulkier ortho substituents on the N aryl moiety. The complexations were achieved either by ligand exchange using (PPh 3 ) 2 Ni( o Tol)Cl or by oxidative addition with Ni(COD) 2 and 2chlorotoluene (Fig. 1 b), forming iminopyridyl Ni II catalysts C1C8 in good yields (66–92% for C1 - C7 and 10% for C8 , Supplementary Figure S2). Ni II complexes C1 - C7 were characterized by 1 H NMR, 13 C NMR, and elemental analysis. In addition, the structures of C1 , C3 , C4 , C5 , C7 , and C8 were determined by singlecrystal Xray diffraction (Fig. 2 a), revealing in all cases square planar geometries. The topographic steric maps (Fig. 2 b) quantify the steric effect imposed by the ligand on the metal center. 34 Catalysts C1 , C3 , C5 and C7 illustrate the limited steric influence provided by the N aryl moiety on the blockage of the metal center. However, the inclusion of the phenyl group on the tether carbon atom increases the buried volume percentage to 47.0% for C4 and 54.5% for C8 compared to their methyl analogues (45.1% for C3 and 47.6% for C7 ). These data support our hypothesis that the substituent on the tether carbon atom can introduce a rotational barrier, enhancing the shielding of the metal center. This is achieved by constraining the rotation of the orthoN -aryl substituents, thereby imposing greater axial bulk and potentially retarding chain-transfer mechanisms. Counterion Study We selected C1 as a model to study the counterion effect for ethylene polymerization by using various cocatalysts. Preliminary polymerizations with C1 were conducted by insitu activation with modifiedMAO (MMAO) and diethylaluminum chloride (Et 2 AlCl) at 20°C (Table 1, entry 1, 2). The MW of the polymers was analyzed using high-temperature gel permeation chromatography (HTGPC) and was found to be 6.5 and 4.0 kg mol − 1 , respectively. Although the organoaluminium cocatalysts produced a highly active species (TOF > 535,700 h − 1 ), the polymerization reaction resulted in a higher dispersity ( Ð = 2.47 and 2.11) for the isolated polymers. The insitu activation of C1 with NaBArF produced PE with higher MW ( M n = 8.5 kg mol − 1 , Table 1, entry 3). However, the catalytic activity was poor (TOF = 12,900 h − 1 ). We suggest that the sodium cation is unable to provide a strong driving force to abstract the halide from the metal center, leading to lower productivity. The poor activity was addressed with AgBArF, which produces AgCl that has a greater lattice energy than NaCl, implying a stronger halide scavenger. 35 Activating C1 with AgBArF produced a 12 times more active catalyst (TOF = 162,900 h − 1 ), but reduced the polymer MW to 6.4 kg mol − 1 (Table 1, entry 4). Other commonly used cocatalysts, such as NaBF 4 and AgPF 6 , were investigated but were found to produce no polymer, illustrating the significant impact the resulting ionpair has on Ni catalyzed olefin polymerization. To further enhance catalytic activity, tris(pentafluorophenyl)borane (B(C 6 F 5 ) 3 ) was used as an additive, with previous reports showing that the organoborane promotes ethylene polymerizations with diimine Ni II catalysts. 19 Although the sequential addition of both B(C 6 F 5 ) 3 and AgBArF significantly increased the activity of C1 (TOF = 274,300 h -1 ), the MW of the resulting PE decreased to 4.6 kg mol -1 (Table 1, entry 5). While the dispersity remained consistent when only using borate cocatalysts, it increased to 2.17 with the addition of B(C 6 F 5 ) 3 . This increase in dispersity suggested a simultaneous addition of AgBArF and B(C 6 F 5 ) 3 could generate active species with differing ionpairs. Remarkably, activating C1 with only B(C 6 F 5 ) 3 produced PE with the highest MW for the tested cocatalysts ( M n = 11.4 kg mol -1 ) and exhibited good catalytic activity (TOF = 102,900 h -1 , entry 6). The difference in catalytic activity between the organoboron cocatalysts can be attributed to the preference in forming either outer or innersphere ionpairs. During polymerization, monomer insertion occurs at the open site of the active catalyst; however this coordination site can be occupied by the cocatalyst. 36 Weakly coordinating anions, such as BArF − , should prefer outer-sphere ion-pairs, facilitating monomer coordination and higher catalytic activity. 37 However, this leads to the more βCH agostic species, which can lead to chain-transfer to monomer by βH elimination and lower MWs, as observed experimentally with the activation of C1 with AgBArF. Activation with B(C 6 F 5 ) 3 produces ClB(C 6 F 5 ) 3 − as the counterion and more favorably lead to inner-sphere ion-pairs, blocking the vacant coordination site and competing with monomer coordination and the formation of βCH agostic species. 38,39 This innersphere coordination would reduce the overall catalytic activity, but would also lead to a lower impact of chaintransfer reactions and to higher MW polymers, 40 as observed with the activation of C1 with B(C 6 F 5 ) 3 . This study suggests that the use of B(C 6 F 5 ) 3 for Ni-catalyzed ethylene polymerization has a profound influence on the chainpropagation to access high MW polymers via an inner-sphere ionpair interactions. DFT Calculations for Counterion Study To validate the above proposition of a stronger inner-sphere action for the ClB(C 6 F 5 ) 3 − anion in this Ni system, a computational investigation was conducted. The DFT calculations aimed at elucidating the structural and energetic differences in the interaction of the cationic nickel catalyst with the BArF − and ClB(C 6 F 5 ) 3 − . The cation ligand was simplified to the unsubstituted pyridine-imine, NC 5 H 4 -2CH = NH, and the PE chain was truncated to a propyl group, generated by insertion of an ethylene molecule into the NiCH 3 bond. For the anion, the full system was used. The geometry optimizations were conducted in the presence of a polarizable continuum with the permittivity of dichloromethane and thermal corrections were applied to obtain standard Gibbs energy values in condensed medium (298 K, 1 mole/L). The cation-anion interaction was investigated only for the most stable NiPr isomer, namely the βagostic complex with the propyl group trans to the pyridine ring (Supplementary Figure S140). For both anions, the addition with displacement of the βagostic CH ligand is exoergic, with a stabilization comparable to that of the coordination of the next ethylene molecule needed for propagation (Fig. 3 ). The addition of ethylene lowers the Gibbs energy of the system by -12.8 kcal mol − 1 , whereas the anion coordination lowers it by -12.1 kcal mol − 1 for BArF − and by -13.2 kcal mol − 1 for ClB(C 6 F 5 ) 3 − . The greater stabilization associated to the ClB(C 6 F 5 ) 3 − coordination is obviously related to the greater donor power of the Cl lone pair in the BCl bond, relative to the F lone pair in the CF bond of the BArF − anion. The latter, however, is also surprisingly efficient, demystifying the concept that BArF − is a non-coordinating anion. 12 In the structure of the [Ni(NC 5 H 4 CHNH)(Pr)] + ClB(C 6 F 5 ) 3 − 41 adduct, the NiCl distance (2.250 Å) is a bit longer than in the optimized [Ni(NC 5 H 4 CHNH)(Pr)Cl] complex (2.225 Å, a lengthening by only 0.025 Å), but the BCl distance (2.255 Å) is much longer than in the free ClB(C 6 F 5 ) 3 − anion (2.003 Å, a lengthening by 0.252 Å). Furthermore, the B atom is pyramidalized (sum of the three CBC angles = 350.7°) to a much lesser extent than in the free ClB(C 6 F 5 ) 3 − anion (340.8°), whereas the neutral B(C 6 F 5 ) 3 Lewis acid has a planar B atom (360°). These structural parameters suggest that the NiClB bonding is better considered as a weak dative interaction from the Cl ligand in the neutral [Ni(NC 5 H 4 CHNH)(Pr)Cl] complex to the B atom in the B(C 6 F 5 ) 3 Lewis acid (Ni-Cl◊B), rather than as a Ni⇓Cl-B dative interaction from the ClB(C 6 F 5 ) 3 − anion to the [Ni(NC 5 H 4 CHNH)(Pr)] + cation. The Gibbs energy of the [Ni(NC 5 H 4 CHNH)(Pr)Cl] + B(C 6 F 5 ) 3 system is -12.2 kcal mol − 1 relative to the βagostic [Ni(NC 5 H 4 CHNH)(Pr)] + cation + ClB(C 6 F 5 ) 3 − anion, namely only + 1.0 kcal mol − 1 relative to the inner-sphere ion-pair. Thus, according to these calculations, the Lewis acidbase interaction between [Ni(NC 5 H 4 CHNH)(Pr)Cl] and B(C 6 F 5 ) 3 is weak but can furnish the βagostic alkyl complex as a kinetically competent intermediate and then the ethylene adduct rather easily. In the structure of the innersphere [Ni(NC 5 H 4 CHNH)(Pr)] + BArF − ionpair, the NiF distance is 2.082 Å and the CF distance of the Nicoordinated CF bond is 1.432 Å, whereas all other noninteracting CF bonds have distances in the 1.35–1.36 Å range, attesting the non-negligible effect of the F◊Ni interaction on the CF bond. In conclusion, the B(C 6 F 5 ) 3 Lewis acid is able to activate the NiCl bond to remove the chloride ion from the nickel coordination sphere, but the cation interaction with ClB(C 6 F 5 ) 3 − competes more efficiently with the ethylene coordination than the interaction with the BArF − anion, although the latter anion is not such a weakly coordinating one in this system. The inner-sphere [Ni(NC 5 H 4 CHNH)(Pr)] + ClB(C 6 F 5 ) 3 −41 ion-pair, better described as a [Ni(NC 5 H 4 CHNH)(Pr)(Cl)]⸱⸱⸱B(C 6 F 5 ) 3 Lewis acid-base adduct, is predicted to be the resting state of the propagation process, rather than the outer-sphere [Ni(NC 5 H 4 CHNH)(Pr)(C 2 H 4 )] + ClB(C 6 F 5 ) 3 − ionpair, and the energy span of the propagation process is marginally greater, resulting in a slower polymerization. Ethylene Polymerization Study with C1C8 at 20°C Since B(C 6 F 5 ) 3 has been found to be an exceptional activator for this system, and yielding higher MW materials, we sought to investigate the substituent effect using B(C 6 F 5 ) 3 for all iminopyridyl complexes. Ethylene polymerizations were conducted at 20°C with 400 psi of ethylene pressure, yielding the results summarized in Table 2. Complexes with the methyl group on the tether carbon atom ( C1 , C3 , C5 , and C7 ) highlight the effect of increasing the steric bulk on the N aryl moiety. No significant difference in MWs was observed for the polymers produced by C1 , C3 and C5 ( M n = 11.4, 7.8, and 11.7 kg mol − 1 ), attesting to the limited effect of steric bulk towards the blockage of the metal center, in line with the marginal increase of the calculated V Bur %. Although the V Bur % increases to only 47.6% in C7 , the polymers produced have the highest MWs of the methyl bridging series ( M n = 153.7 kg mol − 1 ) with lower dispersity ( Ð = 1.77) at 20°C. This is over 10 times higher than any previously tested complex with a methyl-substituted carbon tether and 5 times higher than similar catalysts activated with organoaluminum (Table 2, entry 4). 42 The data suggests that the benzosuberyl ligand provides a rigid steric environment that is a consequence of restricted rotation and further supports the hypothesis that higher MW materials can also be achieved with a more rigid ligand design. Complexes with the phenyl group on the bridging carbon ( C2 , C4 , C6 , and C8 ) should increase the rotational restriction of the N -aryl substituents. C2 exhibited low catalytic activity (TOF = 10,700 h − 1 ) and the resulting PE ( M n = 6.9 kg mol − 1 ) was lower in MW compared with C1 . Surprisingly, C4 exhibited a completely different result and was able to produce PE with MW more than triple compared to C3 ( M n = 23.8 kg mol − 1 ) (Table 2, entry 6). The polymerization results of C4 supported our hypothesis that the phenyl substituent on the tether carbon atom acts as a rotational barrier and is key for producing higher MW polymers. As for C2 , the isopropyl group is not bulky enough even with the phenyl group acting as a rotational barrier, thus resulting in low MW PEs. Similar to C4 , C6 produced much higher MW PE ( M n = 37.0 kg mol − 1 ) with lower dispersity (Table 2, entry 7). This confirmed our hypothesis, where the meta methyl substituents introduced to the benzhydryl groups, alongside the tether carbon rotational barrier, provided higher shielding for the metal center. Synthetic challenges in preparing pure and isomer-free ligands, low complexation, and turnover yields, identified C8 as a complex with undesirable properties. The data suggest that the polymer MW cannot be directly governed by the axial steric environment provided by the ortho substituents of the N aryl moiety. Moreso, emphasis on the design of ligands with a rotational barrier provided by the tether carbon atom substituent may be more effective at producing higher MW polymers. To confirm the thermal stability of the carbyl complexes, C1 was assessed at reaction temperatures ranging from 0-80 °C. The complex is still highly active in polymerization reactions up to 60 °C, which is indicative of good thermal stability (TOF = 94,300 h -1 ). However, at 80 °C, the activity dramatically decreases to 30,000 h -1 which suggests catalyst degradation. We observed that the MW of PEs from C1 is highly dependent on the reaction temperature. With decreasing temperatures, the MW of PEs increased to 65.1 kg mol -1 at 0 °C (Table 3, entry 1). Only oligomers were generated at temperatures above 40 °C (Table 3, entry 4, 5). A similar trend was observed in the iminopyridyl Ni II catalysts C2C7 , with C4 producing high MW polymers at 0 °C ( M n = 164.6 kg mol -1 ) and 5.6 kg mol -1 at 60 °C with the addition of the rotational barrier provided by the tether carbon (Supplementary Table S1 ). Copolymerization Copolymerizations with iminopyridyl Ni II catalysts have been reported to be challenging, where both a high incorporation of polar monomer and high MW PE cannot be synthesized. 43-45 We selected C7 as the model for producing copolymers (Table 4). Interestingly, C7 produced methyl acrylate (MA) copolymers with good incorporation (2.2 mol%) and moderate MW (35.8 kg mol -1 ). Additionally, we tested vinyltriethoxysilane (VTEoS) and vinyl acetate (VAc) which have never been reported as comonomers for iminopyridyl Ni II complexes. Copolymers with about 6 mol% VTEoS incorporation and MWs of 48.1 kg mol -1 were produced and targeting higher MW copolymers (66.3 kg mol -1 ) lowered the incorporation to 3 mol%. For copolymers with VAc, C7 produced polymers with MWs of 53.3 kg mol -1 and incorporation of 0.26 mol%. In general, AgBArF performed better as a cocatalyst for copolymerization over B(C 6 F 5 ) 3 . These data further support the claim that the unique interaction of the inner-sphere organoboron counterion competes with the polar monomer coordination. Branching Density and Distribution Surprisingly, the branching density of PEs obtained from C1 exhibited a linear relationship with respect to the reaction temperature under high pressure conditions where chainwalking should be suppressed (Supplementary Figure S1 ). 46 The control over the branching density ranges from 5 branches/1000 carbon atoms at 0°C to 127 branches/1000 carbon atoms at 80°C and a similar linear branching regulation was observed with complexes C2 - C7 in the same reaction temperature range. For example, C4 ranged from 18 branches/1000 carbon atoms at 0°C to 104 branches/1000 carbon atoms at 60°C. This data suggests that the branching density could be precisely controlled by temperature with the carbyl iminopyridyl Ni II system. Compared to half-sandwich iminopyridyl Ni II complexes, the branching density is limited to a range of 79 branches/1000 carbon atoms at 25°C to 125 branches/1000 carbon atoms at 70°C. 47 We suggest that the unique control of the branching density exhibited by the carbyl Ni II complexes is influenced by the iminopyridine ligand in combination with the innersphere organoboron/Ni ionpair. The ability to produce a wide range of branching densities resulted in the production of diverse materials and prompted further investigation into their unique microstructures. 1 H NMR and differential scanning calorimetry (DSC) showed that the PEs obtained from C1 at 0°C had only 5 branches/1000 carbon atoms and a T m of 127.8°C, classifying the polymer as HDPE. At 20°C, the branching density increased to 25 branches/1000 carbon atoms and a decrease in T m to 108.6°C, producing LDPE. Minor elastomeric properties were observed from the PE obtained at 40°C, with a branching density of 56 branches/1000 carbon atoms and a T m of 64.4°C. Wax-like materials were generated at 60°C and a branching density of 95 branches/1000 carbon atoms and a T m of 9.3°C, and an oligomeric oil was formed at 80°C with a sub-zero T m (Table 3, entries 1–5). In summary, a single catalyst can produce several types of PEs with broad branching densities. This versatility is achieved without the need for expensive comonomers, making it highly desirable in polyolefin syntheses and processes. We point out that it is unusual for these complexes to produce a wide variety of PE at high pressures, where chainwalking should be retarded. The material properties of the PE produced by organoboron activated complexes suggest a unique branching microstructure commonly achieved through αolefin copolymerization, which introduces shortchain branches (SCBs). It has been understood that the controlled incorporation of SCBs, where the branch length is 5 carbon atoms or less, can dramatically impact the mechanical properties of PE. 48,49 Therefore, the analysis of the branching microstructure of polymers produced by C1 under high ethylene pressure was conducted using quantitative 13 C NMR spectroscopy (Supplementary Figures S58-63) and is included in Table 3. 50,51 At 0 °C, only methyl branches are observed. Increasing the temperature to 20 °C induces the incorporation of ethyl, propyl, and a large percentile of long-chain branches (LCBs). Additional ethyl and propyl branches were observed in the polymer at 40 °C, with new butyl and amyl branches being detected. At 60 and 80 °C, all SCBs were incorporated and increased for amyl and LCBs at the expense of methyl branches. Current iminechelated Ni II complexes must utilize low pressure conditions and/or elaborate ligand designs to promote chainwalking and tailor the polymer microstructure. 52-54 However, this strategy is not effective as the incorporation of SCBs is negligible. Since our system produces shortchain branches under high pressure conditions and is not supported by established mechanistic understandings, we sought to further investigate the underlying chainwalking mechanism through computational studies. Therefore, additional DFT calculations were conducted for C1 with respect to temperatures ranging from 0 to 80 °C. DFT Calculations for ChainWalking Mechanism The polymerization is modeled from the βCH agostic species, the resting state, with a propagating polymer chain 1 (Supplementary Figure S141) and can proceed through two pathways (Fig. 4 a). The free energy profile at 60°C is used as a representative data set to discuss the branching distribution and energy profile (Fig. 4 b). The remaining free energy profiles for the tested temperature range are included as Supplementary Figures S142-145. The first pathway is a coordination/insertion of ethylene to produce a linear polymer ( Linear ). Monomer coordination must overcome a free energy barrier ( TS 1MC ) of 16.3 kcal mol − 1 and is exergonic by 3.9 kcal mol − 1 . Alternatively, the agostic species 1 can undergo βhydride elimination ( TS 2BHE ) to form the olefin π complex 2 with an energy barrier of 12.2 kcal mol − 1 . Complex 2 then can undergo 2,1reinsertion ( TS 23RI ), with an energy barrier of 5.1 kcal mol − 1 and generate the new βCH agostic species 3 . This process is exergonic by -12.6 kcal mol − 1 and is favored over direct ethylene coordination insertion by 4.7 kcal mol − 1 . The agostic species 3 can again either undergo monomer coordination ( TS 3MC ) with an energy barrier of 8.1 kcal mol − 1 to produce a methyl branch ( Methyl ) or βhydride elimination ( TS 4BHE ) for further chainwalking. However, the 13.0 kcal mol − 1 energy barrier for chain-walking suggests that methyl branch formation is more favorable, consistent with the predominant branch experimentally observed at all temperatures. Once the agostic species 3 crosses the barrier TS 4BHE , the olefin π complex 4 is formed and can undergo 3,2reinsertion ( TS 45RI ), with a minimal barrier of only 3.0 kcal mol − 1 , to form βCH agostic complex 5 in an exergonic step (-6.1 kcal mol − 1 ). After the formation of complex 5 , βelimination must overcome a barrier of 23.2 kcal mol − 1 ( TS 6BHE ). The significantly lower barrier of 5.2 kcal mol − 1 ( TS 5MC ) for ethylene insertion to produce ethyl branched ( Ethyl ) polymer in a mildly exergonic step (-0.3 kcal mol − 1 ) agrees well with the measured formation of ethyl branches starting from 20°C in our experiments. Following βelimination from complex 5 , the further reinsertion step is barrierless for all studied temperatures and favors the spontaneous formation of βCH agostic complex 7 . The overall chainwalking step from 5 to 7 is endergonic by 5.3 kcal mol − 1 . From complex 7 the barrier for propyl branch formation ( TS 7MC ) is 6.5 kcal mol − 1 and is marginally lower than the barrier of 9.2 kcal mol − 1 ( TS 8BHE ) for βelimination leading to 8 and its spontaneous conversion to 9 at temperatures above 40°C. Next, βelimination to olefin π complex 10 , followed by the 6,5reinsertion to βCH agostic complex 11 is the precursor to form amyl branches. The βelimination step is endergonic by 13.0 kcal mol − 1 with a barrier of 16.6 kcal mol − 1 ( TS 10BHE ), but the reinsertion step is thermodynamically favorable and is exergonic. Although the calculated activation barrier value of 22.3 kcal mol − 1 for reinsertion ( TS 1011RI ) suggests a low amount of amyl branches, reactions above 40°C have moderate percent incorporation (Table 3, entries 3–5). The percentage of amyl and LCBs produced can be attributed to the mechanism proposed by Wu and coworkers, where the Ni complex chainwalks to a terminal position on an existing methyl branch, forming a new primary Nialkyl species together with a longchain branch, which can include amyl. 52 To rationalize the observed trends in branching behavior with temperature, we have calculated the free energy changes of relevant intermediate and transition states for chain-walking between 0 and 80°C. Figure 5 shows that free energies decrease with increasing temperature, except for TS 6BHE , 7 , and 8 , which show minor destabilization with temperature. Thus, higher temperatures should favor the gradual incorporation of longer branches, which is consistent with the branching distribution reported in Table 3. While the barrier associated with 8 increases by less than 0.2 kcal mol − 1 from 0–80°C, the increase in thermal energy ( k b T ) allows the reaction to proceed at elevated temperatures. This also agrees well with the experimental observation of butyl branches starting at 40°C, which is the first branched product after 8 . Here, a new class of bench-top iminopyridyl Ni II complexes were prepared with an o -tolyl carbyl substituents which enables an investigation of the effect of inner- and outer-sphere ion-pairs for olefin polymerization. Earlytransition metal complexes demonstrate the importance of the counterion controlling polyolefin microstructures, but the influence and impact of counterion effects in late transition complexes, specifically for imine-chelated Ni II complexes have been largely unexplored, due to the absence of a suitable thermodynamically stable complex. We demonstrated that with well-defined, inner-sphere ClB(C 6 F 5 ) 3 − counterion leads to higher MW materials and the possibility for controlled short-chain branch incorporation utilizing increasing reaction temperatures. This led to materials with properties comparable to HDPE, LDPE, elastomers, waxes, and oils. Additionally, we showed that the substituents on the tether carbon can act as a rotational barrier imposing more axial bulk around the metal center and favor chain-propagation. This highlights the importance of substituent placement on the tether carbon moiety, instead of the more traditional ligand design focusing on the aryl imine. We anticipate that this study will invigorate the exploration of inner-sphere counterions with the extensive iminopyridine ligand catalog for the synthesis of high value polyolefins with unique branching characteristics and properties. METHODS All manipulations of air- and water-sensitive compounds were conducted under an inert atmosphere using glovebox, Schlenk and high-vacuum techniques, unless otherwise noted. Deuterated solvents were purchased from Cambridge isotopes and used as received. 1 H and 13 C NMR were acquired on JEOL JNMECA 400 (400 MHz), JNMECZ400S (400 MHz), or ECA-600 (600 MHz) spectrometers. Chemical shifts are measured relative to residual solvent peaks as an internal standard set to δ 7.26 and δ 77.16 (chloroform- d 1 (CDCl 3 )), δ 5.32 and δ 53.84 (methylene chlorided 2 (CD 2 Cl 2 )) and δ 6.00 and δ 73.78 (1,1,2,2tetrachloroethaned 2 (C 2 D 2 Cl 4 ,)) for 1 H and 13 C, respectively. Quantitative 13 C NMR spectra of polymers were recorded on the ECA-600 (600 MHz) spectrometer at 125°C, in C 2 D 2 Cl 4 with Cr(acac) 3 as a relaxation agent (0.05 M). Electrospray ionization mass spectrometry (ESIMS) experiments were performed using a Thermo Scientific Q Exactive Focus instrument by the Mass Spectrometry Facility at Texas A&M in College Station, Texas. Gel Permeation Chromatography (GPC) was performed using a Tosoh EcoSEC HLC-8321 GPC/HT system equipped with an autosampler, three TSKgel GMHhrH(S) HT2 columns, builtin dual flow refractive index (RI) detector, and viscometer. GPC analyses were conducted in HPLC grade 1,2,4trichlorobenzene with a flow rate of 1.0 mL/min at 160°C calibrated with polystyrene standards. The elemental analyses were performed by Atlantic Microlab, lnc. in Norcross, Georgia. Differential Scanning Calorimetry (DSC) investigations were conducted on a TA Instruments DSC 2500 system. The samples were heated from 25°C to 180°C, cooled to − 90°C, and then heated to 180°C at a rate of 10°C/minute. DSC data were obtained from the second heating cycle. The polymer branching density and distribution were calculated using established proton and carbon NMR signals. 51 Synthesis of iminopyridyl Ni II complexes C1-C8 For C1 , C3 , C5 , C7 , and C8 : To a dried 100 mL round-bottomed flask filled with nitrogen was added (PPh 3 ) 2 Ni( o -tol)Cl (500 mg, 0.7 mmol) and 0.77 mmol of the corresponding iminopyridine ligand. Toluene (20 mL) was injected into the reaction and stirred at room temperature. The red/purple suspensions were formed after stirring for 16 hours. 10 mL of pentane was added to the reaction, and the precipitate was filtered and collected. The catalyst was dissolved in DCM and filtered through celite. The filtrate was concentrated under vacuum, and the resulting product was purified via recrystallization from dichloromethane and pentane. C1 : Anal. Calcd. for C 26 H 31 ClN 2 Ni: C, 67.06; H, 6.71; N, 6.02; Found: C, 67.12; H, 6.76; N, 5.94. C2 : Anal. Calcd. for C 31 H 33 ClN 2 Ni: C, 70.55; H, 6.30; N, 5.31; Found: C, 70.42; H, 6.27; N, 5.25. C3 : Anal. Calcd for C 47 H 41 ClN 2 Ni: C, 77.54; H, 5.68; N, 3.85. Found: C, 77.19; H, 5.66; N, 3.87. C5 : Anal. Calcd for C 55 H 57 ClN 2 Ni: C, 78.62; H, 6.84; N, 3.33. Found: C, 78.61; H, 6.79; N, 3.31. C7 : Anal. Calcd for C 51 H 45 ClN 2 Ni: C, 78.53; H, 5.81; N, 3.59. Found: C, 78.25; H, 5.72; N, 3.48. For C4 and C6 : To a flame-dried 100 mL round-bottomed flask filled with nitrogen was added Ni(COD) 2 (137.5 mg, 0.5 mmol) and 0.5 mmol of the corresponding iminopyridine ligand. 2-chlorotoluene (4 mL) was injected into the reaction and stirred at room temperature. The purple suspensions were formed after stirring for 16 hours. The reaction was diluted with DCM and then filtered through celite. The filtrate was concentrated, and the resulting product was purified via recrystallization from chloroform and pentane. C4 : Anal. Calcd for C 52 H 43 ClN 2 Ni: C, 79.05; H, 5.49; N, 3.55. Found: C, 78.88; H, 5.52; N, 3.51. C6 : Anal. Calcd for C 60 H 59 ClN 2 Ni: C, 79.87; H, 6.59; N, 3.10. Found: C, 79.60; H, 6.50; N, 3.10. General Procedure for ethylene homo- and co-polymerization A 300 mL Series 5521 Compact Bench Top Reactor System (Parr Instrument Company) was heated to 110°C for at least 1 hour under vacuum and then cooled to the desired reaction temperature. A heating control system or a chiller kept the reactor temperature constant. Toluene was injected under a positive ethylene flow and the reactor was subsequently pressurized with ethylene to 200 psi and maintained for 10 minutes. The reactor was vented and repressurized to 200 psi of ethylene and maintained for another 10 minutes. The reactor was then vented, and 5.0 mL of methylene chloride solution of nickel catalyst and 5.0 mL methylene chloride solution of the organoboron cocatalyst were sequentially injected under ethylene flow. For copolymerization, the comonomer was injected after the catalyst solution. The reactor was sealed, pressurized to the desired ethylene pressure, and stirred for the desired reaction time. The reactor was then carefully vented, quenched, and poured into a solution of 400 mL methanol. The polymer was filtered and dried under vacuum to reach a constant weight. Alternatively, the reaction solution can be quenched and concentrated under vacuum before being washed with methanol to isolate the polymer before drying under vacuum. Computation details for counterion study The computational work was carried out using the Gaussian16 suite of programs. 55 The geometry optimizations were performed without any symmetry constraint using the B3LYP functional, the SDD basis functions for the nickel atom, which included an ECP and an f polarization function (α = 3.130) 56 , and the 6-311G(d,p) basis functions for all other light atoms (Cl, F, O, N, C, B, H). The effects of dispersion forces (Grimme’s D3 empirical method) 57 and solvation in dichloromethane (ε = 8.93) by SMD 58 were included during the optimization. The ZPVE, PV, and TS corrections at 298 K were obtained with Gaussian16 from the solution of the nuclear equation using the standard ideal gas and harmonic approximations at T = 298.15 K, which also verified the nature of all optimized geometries as local minima or first-order saddle points. A correction of 1.95 kcal mol − 1 was applied to all G values to change the standard state from the gas phase (1 atm) to solution (1.0 M). 59 Computation details for chainwalking study The density functional theory (DFT) calculations were conducted using the Gaussian16 package. 55 The initial state, illustrated in Supplementary Figure S141, consisted of a polymer chain comprising 7 carbon atoms. Each structure was optimized using the generalized gradient approximation (GGA) 60,61 BP86 62–64 /BSI level with spin polarization, and harmonic vibration frequencies were computed to determine the thermodynamic data. For the BSI level, the carbon (C), hydrogen (H), and nitrogen (N) atoms were evaluated using the 6-31G* basis set. The nickel (Ni) atom was treated with the quasi-relativistic LANL2DZ ECP effective core potential. 65 To obtain more reliable relative energies, single-point calculations were performed on the optimized structures using the BP86D3 level, which incorporates Grimme's DFTD3 correction 57,66 , and the BSII level, accounting for the solvation effect of toluene using the SMD 58 solvation model. In BSII, the 6-31G* basis set was employed for carbon (C), hydrogen (H), oxygen (O), and nitrogen (N) atoms, while the nickel (Ni) atom was treated using the Stuttgart/Dresden effective core potential (ECP) and the corresponding basis sets. 67 The free energies in solution, necessary for describing energy profiles, were obtained through solvation single-point calculations along with the gas-phase Gibbs free energy correction. 68,69 Transition states were calculated using the QST3 method implemented in Gaussian. Declarations DATA AVAILABLITY The X-ray crystallographic data for complexes C1 , C3 , C4 , C5 , C7 , and C8 has been deposited at the Cambridge Crystallographic Data Center (CCDC) under deposition numbers 2320308-2320313. These data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif. Supplementary Information contains detailed experimental procedures, characterization data, X-ray crystallography (Supplementary Figures S134-S139), and 1 H and 13 C NMR data for the ligands and complexes (Supplementary Figures S3-S22), as well as reaction temperature study (Supplementary Table S1), 1 H and 13 C NMR data for the polymers (Supplementary Figures S23-S63), GPC (Supplementary Figures S64-S98), DSC (Supplementary Figures S99-S133), branching trend (Supplementary Figure S1), and DFT data (Supplementary Figures S140-S145). All data can be supplied by the authors upon reasonable request. Acknowledgements The authors H. S. R., Y-S. L. and E.H. thank the Robert A. Welch Foundation for funding (H-E-0041and E-2066-202110327) through the Center of Excellence in Polymer Chemistry and acknowledge the National Science Foundation (CHEM-2108576) for supporting parts of this work. R.P. thanks the CALMIP Mesocenter of the University of Toulouse for the allocation of computational resources. S.S.S. and L.C.G. were supported by NSF EFRI Award # 2029359, and acknowledge the use of the Carya, Opuntia, and Sabine Clusters and the advanced support from the Research Computing Data Core at the University of Houston. Contributions H.S.R. and Y-S.L. conceived the project. H.S.R. synthesized and characterized the complexes. H.S.R. and Y-S.L. performed experimental studies and polymer analysis. H.S.R., Y-S.L., and E.H. drafted the initial manuscript. H.S.R., Y-S.L., and E.H. designed and edited figures. H.S.R., Y-S.L., S.S.S., L.C.G., R.P., and E.H. edited and revised the text. 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Ethylene polymerization of C1 with different cocatalysts a Entry Cocatalyst Time (min) Yield (g) Productivity (kg mol -1 Ni ·h) TOF (10 3 )(h −1 ) Branches /1000C b M n c (kg mol -1 ) Ð c T m d (°C) 1 e MMAO (200 eq.) 5 3.0 18,000 642.9 27 6.5 2.47 109.3 2 e Et 2 AlCl (200 eq.) 5 2.5 15,000 535.7 40 4.0 2.11 102.7 3 NaBArF (1.2 eq.) 10 0.3 360 12.9 26 8.5 1.98 108.3 4 AgBArF (1.2 eq.) 10 3.8 4,560 162.9 32 6.4 2.00 105.2 5 f AgBArF (1.2 eq.) 5 3.2 7,680 274.3 41 4.6 2.17 104.6 6 B(C 6 F 5 ) 3 (10 eq.) 10 2.4 2,880 102.9 25 11.4 1.93 108.6 Conditions: a 5 μmol of C1 , 400 psi ethylene, 45 mL of toluene, 20 °C. b Determined by 1 H NMR in D 2 ‑tetrachloroethane at 125 °C. c Determined by GPC in 1,2,4-trichlorobenzene at 160 °C using polystyrene calibration. d Determined by differential scanning calorimetry. e 2 μmol of C1 . f Included 10 equivalents of B(C 6 F 5 ) 3. TOF = Turn-Over Frequency, M n = Number-Average Molecular Weight, Ð = Dispersity, T m = Melting Temperature. Table 2. Ethylene polymerization of C1‑C8 at 20 °C a Entry Catalyst Time (min) Yield (g) Productivity (kg mol -1 Ni ·h) TOF (10 3 )(h −1 ) Branches /1000C b M n c (kg mol -1 ) Ð c T m d (°C) 1 e C1 10 2.4 2,880 102.9 25 11.4 1.93 108.6 2 C3 10 1.7 1,020 36.4 30 7.8 1.94 101.0 3 C5 10 1.6 960 34.3 37 11.7 1.97 99.7 4 C7 10 0.8 480 16.8 26 153.7 1.77 101.5 5 e C2 60 1.5 300 10.7 36 6.9 1.92 102.1 6 C4 60 0.9 90 3.2 49 23.8 1.75 112.0 7 C6 60 1.2 120 4.3 45 37.0 1.62 82.9 8 C8 180 0.5 167 0.6 42 71.3 2.06 91.5 Conditions: a 10 μmol of Ni catalyst, 10 equivalent of B(C 6 F 5 ) 3 , 400 psi ethylene, 45 mL of toluene. b Determined by 1 H NMR in D 2 ‑tetrachloroethane at 125 °C. c Determined by GPC in 1,2,4-trichlorobenzene at 160 °C using polystyrene calibration. d Determined by differential scanning calorimetry. e 5 μmol of Ni. TOF = Turn-Over Frequency, M n = Number-Average Molecular Weight, Ð = Dispersity, T m = Melting Temperature. Table 3. Ethylene polymerization of C1 at 0-80 °C a Entry Temp (°C) Time (min) Yield (g) Productivity (kg mol ‑1 Ni ·h) TOF (10 3 )(h −1 ) M n b (kg mol -1 ) Ð b T m c (°C) Branches /1000C d Branching Distribution (%) e Me Et Pr Bu Am Lg 1 0 30 1.1 440 15.7 65.1 1.65 127.8 5 100 0 0 0 0 0 2 20 10 2.4 2,880 102.9 11.4 1.93 108.6 25 78.9 3.1 1.9 0 0 16.1 3 40 10 1.8 2,160 77.1 3.7 1.67 64.4 56 68.0 3.4 2.6 2.1 3.8 20.0 4 60 10 2.2 2,640 94.3 2.0 1.51 9.3 95 65.7 4.1 2.9 2.3 4.4 20.7 5 80 10 0.7 840 30.0 1.0 1.74 -23.6 127 57.8 4.2 2.2 2.3 6.0 27.5 Conditions: a 5 μmol of Ni catalyst, 10 equivalent of B(C 6 F 5 ) 3 , 400 psi ethylene, 45 mL of toluene. b Determined by GPC in 1,2,4-trichlorobenzene at 160 °C using polystyrene calibration. c Determined by differential scanning calorimetry. d Determined by 1 H NMR in D 2 ‑tetrachloroethane at 125 °C. e Determined by 13 C NMR in D 2 ‑tetrachloroethane at 125 °C. TOF = Turn-Over Frequency, M n = Number-Average Molecular Weight, Ð = Dispersity, T m = Melting Temperature, Me = Methyl, Et = Ethyl, Pr = Propyl, Bu = Butyl, Am = Amyl, Lg = Large. Table 4. Ethylene/polar monomer Copolymerization of C7 a Entry Monomer [M] Temp. (°C) Yield (g) TOF (10 3 )(h −1 ) Branches /1000C b M n c (kg mol -1 ) Ð c Incorp. (mol %) T m d (°C) T g d (°C) 1 e - 40 3.2 11.4 57 111.6 1.71 - 68.7 -36.0 2 VTEoS [0.5] 40 0.8 0.7 52 66.3 1.60 3.1 56.2 -55.0 3 f VTEoS [0.5] 60 1.2 2.1 69 33.0 1.68 4.6 27.2 -64.7 4 VTEoS [1.0] 40 0.45 0.4 50 48.1 1.79 5.9 46.8 -63.6 5 g MA [0.1] 40 0.15 0.06 61 55.6 1.57 0.34 73.1 -39.2 6 g MA [0.1] 60 0.3 0.1 83 35.8 1.66 2.2 26.4 -51.9 7 g VAc [0.25] 60 0.5 0.2 78 53.3 1.65 0.26 46.9 -49.8 Conditions: a 20 μmol of C7 , 1.2 equivalents of AgBArF, 400 psi ethylene, 45 mL of toluene, 120 min. b Determined by 1 H NMR in D 2 ‑tetrachloroethane at 125 °C. c Determined by GPC in 1,2,4-trichlorobenzene at 160 °C using polystyrene calibration. d Determined by differential scanning calorimetry. e 10 μmol of C7 , 60 min. f 10 umol of C7 , g 240 min. [M] = molar concentration, TOF = Turn-Over Frequency, M n = Number-Average Molecular Weight, Ð = Dispersity, T m = Melting Temperature, VTEoS = vinyltriethoxysilane, MA = methyl acrylate, VAc = vinyl acetate. Additional Declarations There is NO Competing Interest. Supplementary Files CIFFilesNiPaper.zip Data Set 1 SINat.Comm.pdf Unraveling Organoboron/Nickel Ion-Pair Interactions via Benchtop-Stable Carbyl Iminopyridyl NiII Complexes for Olefin Polymerization SI Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-3773688","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":264716829,"identity":"9c7e24f8-2049-407a-872f-8d6dabf7ded8","order_by":0,"name":"Eva 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Toulouse","correspondingAuthor":false,"prefix":"","firstName":"Rinaldo","middleName":"","lastName":"Poli","suffix":""},{"id":264716837,"identity":"a73cb441-4180-4886-9f93-2fb100216ae3","order_by":6,"name":"Lars Grabow","email":"","orcid":"https://orcid.org/0000-0002-7766-8856","institution":"University of Houston","correspondingAuthor":false,"prefix":"","firstName":"Lars","middleName":"","lastName":"Grabow","suffix":""}],"badges":[],"createdAt":"2023-12-18 21:20:37","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-3773688/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-3773688/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":49115143,"identity":"8a54b8c5-9df4-4869-bd9e-76e26e21c8b7","added_by":"auto","created_at":"2024-01-03 10:33:07","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":521270,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSynthesis of carbyl iminopyridyl Ni\u003c/strong\u003e\u003csup\u003e\u003cstrong\u003eII\u003c/strong\u003e\u003c/sup\u003e\u003cstrong\u003e complexes.\u003c/strong\u003e \u003cstrong\u003ea\u003c/strong\u003e Synthesis of iminopyridine ligands \u003cstrong\u003eL1\u003c/strong\u003e‑\u003cstrong\u003eL8\u003c/strong\u003e. \u003cstrong\u003eb\u003c/strong\u003e Complexation of ligands to form Ni\u003csup\u003eII\u003c/sup\u003e catalysts \u003cstrong\u003eC1\u003c/strong\u003e‑\u003cstrong\u003eC8\u003c/strong\u003e.\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-3773688/v1/b41525a49865ae6561c8e8c5.jpg"},{"id":49114648,"identity":"104767cd-063d-4875-956c-f13846974cca","added_by":"auto","created_at":"2024-01-03 10:25:07","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":239318,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eX-Ray Structures of carbyl iminopyridyl Ni\u003c/strong\u003e\u003csup\u003e\u003cstrong\u003eII\u003c/strong\u003e\u003c/sup\u003e\u003cstrong\u003e complexes.\u003c/strong\u003e \u003cstrong\u003ea\u003c/strong\u003e Stick model of \u003cstrong\u003eC1\u003c/strong\u003e, \u003cstrong\u003eC3\u003c/strong\u003e, \u003cstrong\u003eC4\u003c/strong\u003e, \u003cstrong\u003eC5\u003c/strong\u003e, \u003cstrong\u003eC7\u003c/strong\u003e, and \u003cstrong\u003eC8\u003c/strong\u003e. \u003cstrong\u003eb \u003c/strong\u003eSteric map and V\u003csub\u003eBur\u003c/sub\u003e% of \u003cstrong\u003eC1\u003c/strong\u003e, \u003cstrong\u003eC3\u003c/strong\u003e, \u003cstrong\u003eC4\u003c/strong\u003e, \u003cstrong\u003eC5\u003c/strong\u003e, \u003cstrong\u003eC7\u003c/strong\u003e, and \u003cstrong\u003eC8\u003c/strong\u003e.\u003c/p\u003e","description":"","filename":"2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-3773688/v1/d75e3a99a838e3cbb5173b41.jpg"},{"id":49114646,"identity":"6a4b8790-7919-4151-91f6-5de16ffb113d","added_by":"auto","created_at":"2024-01-03 10:25:07","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":244429,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eCation-anion ion-pair interaction with C1.\u003c/strong\u003e Gibbs energy profile (values in kcal mol\u003csup\u003e-1\u003c/sup\u003e) for the interaction between the [Ni(NC\u003csub\u003e5\u003c/sub\u003eH\u003csub\u003e4\u003c/sub\u003eCHNH)(Pr)]\u003csup\u003e+\u003c/sup\u003e cation (center) and the BArF\u003csup\u003e-\u003c/sup\u003e and ClB(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e-\u003c/sup\u003e anions (left) and ethylene monomer (right).\u003c/p\u003e","description":"","filename":"3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-3773688/v1/4b6c6eeb56dc048bf0a1f3f2.jpg"},{"id":49114650,"identity":"3303f9fb-3ac5-43ae-91db-de90c3f0bd77","added_by":"auto","created_at":"2024-01-03 10:25:07","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":443396,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eMechanism and free energy diagram for chain-walking mechanism.\u003c/strong\u003e \u003cstrong\u003ea\u003c/strong\u003e Chain-walking mechanism. \u003cstrong\u003eb \u003c/strong\u003eFree energy diagram for chain-walking and propagation for \u003cstrong\u003eC1\u003c/strong\u003e calculated from DFT at 60 °C. TS: transition state; BHE: β-hydride elimination; RI: reinsertion; MC: monomer coordination.\u003c/p\u003e","description":"","filename":"4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-3773688/v1/71d7978c590a20a38858a433.jpg"},{"id":49114649,"identity":"45057760-dd6d-4b8c-8bc7-d23e18b1e32f","added_by":"auto","created_at":"2024-01-03 10:25:07","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":186546,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eTemperature driven variations in free energy\u003c/strong\u003e. Free energies for intermediates and transition states encountered along the chain‑walking mechanism are shown relative to their respective values at 0 °C.\u003c/p\u003e","description":"","filename":"5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-3773688/v1/5c74e1313f488e4b4a875539.jpg"},{"id":55034908,"identity":"6ec5c4b6-28f1-4263-b028-c4e8ef892161","added_by":"auto","created_at":"2024-04-20 19:53:24","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1048521,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-3773688/v1/16ea9130-2d9f-4136-85bc-ecb74559a8a2.pdf"},{"id":49115144,"identity":"b15953ec-799d-434d-a371-febec7bc65c7","added_by":"auto","created_at":"2024-01-03 10:33:07","extension":"zip","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":1442217,"visible":true,"origin":"","legend":"Data Set 1","description":"","filename":"CIFFilesNiPaper.zip","url":"https://assets-eu.researchsquare.com/files/rs-3773688/v1/94ee78b0aac3f15035cd7ed4.zip"},{"id":49114652,"identity":"7eca164b-74fc-4c74-8554-a723b22185e0","added_by":"auto","created_at":"2024-01-03 10:25:07","extension":"pdf","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":8125283,"visible":true,"origin":"","legend":"\u003cp\u003eUnraveling Organoboron/Nickel Ion-Pair Interactions via Benchtop-Stable Carbyl Iminopyridyl NiII Complexes for Olefin Polymerization SI\u003c/p\u003e","description":"","filename":"SINat.Comm.pdf","url":"https://assets-eu.researchsquare.com/files/rs-3773688/v1/158c8a07602412f4c9bff6cc.pdf"}],"financialInterests":"There is \u003cb\u003eNO\u003c/b\u003e Competing Interest.","formattedTitle":"\u003cp\u003eUnraveling Organoboron/Nickel Ion-Pair Interactions via Benchtop-Stable Carbyl Iminopyridyl Ni\u003csup\u003eII\u003c/sup\u003e Complexes for Olefin Polymerization\u003c/p\u003e","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eThe success of polymeric materials is rooted in their versatility, high performance, and affordable production.\u003csup\u003e1\u0026ndash;3\u003c/sup\u003e Among these materials, polyolefins continue to make up about half of the polymer production due to their exceptional chemical resistance and tunable material properties.\u003csup\u003e4\u003c/sup\u003e In general, the physical properties of polyolefins are directly related to their molecular weight (MW) and microstructure, which is highly dependent on the involved catalytic system. The development of the Brookhart-type catalysts launched the field of late-transition metal-catalyzed olefin polymerization.\u003csup\u003e5\u003c/sup\u003e These α-diimine Pd\u003csup\u003eII\u003c/sup\u003e and Ni\u003csup\u003eII\u003c/sup\u003e complexes are highly tolerant of polar monomers and provide control over polymer microstructure through their unique \"chainwalking\" mechanism.\u003csup\u003e6\u0026ndash;8\u003c/sup\u003e The α-diimine Ni\u003csup\u003eII\u003c/sup\u003e systems are attractive due to their high catalytic activity and earth abundancy of Ni. Over the years, there has been a surge in the development of ligands aimed at the control of the polymer microstructure to influence material properties. However, effective microstructure control has required the use of increasingly complex ligands.\u003csup\u003e9\u0026ndash;11\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eThese polymerization systems rely not only on the transition metal complex but also on the cocatalyst used for activation. The ionic interaction between the metal complex and the counterion has been demonstrated to have a significant impact on the catalytic activity and polymer architecture in transition metalcatalyzed olefin polymerizations.\u003csup\u003e12,13\u003c/sup\u003e However, there are no available catalytic systems that allows for the investigation of inner- and outersphere counterion effects in [\u003cem\u003eN,N\u003c/em\u003e]chelated Ni\u003csup\u003eII\u003c/sup\u003e complexes. Diimine Pd\u003csup\u003eII\u003c/sup\u003e complexes can be designed with a carbyl ligand to be activated by both organoaluminum and organoboron cocatalysts. However, diimine Ni\u003csup\u003eII\u003c/sup\u003e analogs require dihalide ligands for olefin polymerization, limiting activation to bifunctional organoaluminium cocatalysts such as methylaluminoxane (MAO), which functions through halide abstraction and metal alkylation for coordination polymerization.\u003csup\u003e12,14\u003c/sup\u003e Moreover, MAO limits the indepth study of the influence of ligand design and reaction conditions to tailor the microstructure of polymers, due to the limited understanding of the anionic macrostructure.\u003csup\u003e15\u003c/sup\u003e Conversely, cocatalysts other than organoaluminium result in a well-defined anionic species, enabling the investigation of the ionpair that governs the polymeric characteristics and properties.\u003csup\u003e16\u003c/sup\u003e However, these cocatalysts require an carbyl precursor as they activate only through halide abstraction. Unfortunately, carbyl diimine Ni\u003csup\u003eII\u003c/sup\u003e complexes are unstable due to the lability of the NiC bond, as the diimine ligand cannot form a stable complex under ambient conditions. Stable η\u003csup\u003e3\u003c/sup\u003e and η\u003csup\u003e5\u003c/sup\u003ecoordinated cationic diimine Ni complexes have been reported; however, they require the use of organoaluminum cocatalysts for olefin polymerization.\u003csup\u003e17\u0026ndash;20\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eTo evaluate the impact of counterions on iminechelated Ni\u003csup\u003eII\u003c/sup\u003e complexes, it is therefore crucial to develop a robust carbyl Ni\u003csup\u003eII\u003c/sup\u003e precatalyst. Such an approach could pave the way for unprecedented control over the polymer microstructure and MW by shifting the focus from complex ligand design to the utilization of ion-pairs. Specifically, our aim was to create an alkyl- or arylfunctionalized Ni precatalyst that could be activated solely by a scavenger, without the need for an alkylation process to generate the cationic complex for olefin polymerization. These complexes would serve as an ideal system for a variety of activators, expanding beyond the limitation of organoaluminum cocatalysts. Thus, we selected iminopyridine complexes, with the [\u003cem\u003eN\u003c/em\u003e,\u003cem\u003eN\u003c/em\u003e]ligand backbone serving as a diimine analog and the pyridine moiety acting as a stronger \u003cem\u003eσ\u003c/em\u003edonor to help stabilize the labile NiC bond.\u003csup\u003e21\u003c/sup\u003e However, in contrast to symmetric diimine ligands, the addition of axial steric bulk does not promote chain-propagation and produces low MW polyethylene (PE).\u003csup\u003e22\u0026ndash;26\u003c/sup\u003e More importantly, air-stable iminopyridyl mesityl Ni\u003csup\u003eII\u003c/sup\u003e complexes have been successfully synthesized using straightforward approaches. However, these catalysts were only found effective for cross-coupling reactions.\u003csup\u003e27\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eIn this contribution, we disclose the synthesis of a new class of benchtop, airstable iminopyridyl Ni\u003csup\u003eII\u003c/sup\u003e complexes, \u003cb\u003eC1C8\u003c/b\u003e, which feature an \u003cem\u003eo\u003c/em\u003etolyl ligand as the carbyl substituent. We investigate the significance and effect of the ionpair for ethylene polymerization, and its role in tailoring branching characteristics and density of the produced PE with respect to the reaction conditions. The complexes are designed with a focus on a rotational barrier provided by either a methyl or phenyl group on the carbon tether and the \u003cem\u003eortho\u003c/em\u003esubstituents on the aryl imine. Various cocatalysts such as modifiedMAO, sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (NaBArF), and organoboranes were evaluated for ethylene polymerization. Furthermore, we demonstrate the use of B(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e as the primary cocatalyst for carbyl Ni\u003csup\u003eII\u003c/sup\u003e iminopyridyl complexes, producing active complexes and yielding high MW PE (\u003cem\u003eM\u003c/em\u003e\u003csub\u003en\u003c/sub\u003e \u0026gt; 100 kg mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e). Density functional theory (DFT) studies support the establishment of a reversible innersphere anion coordination with ClB(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e, which reduces the overall catalytic activity, but allows the production of higher MW polymers. Moreover, the activation of these complexes with B(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e reveals that the substituent on the carbon tether greatly influences the polymer MWs through a rotational restriction of the \u003cem\u003eortho\u003c/em\u003esubstituents on the \u003cem\u003eN\u003c/em\u003earyl moiety. The chain-walking behavior led to controlled branching densities and short-chain branching distributions, ranging from methyl to butyl, depending on the reaction temperature (0\u0026ndash;80\u0026deg;C), producing polymers with diverse macrostructures. DFT studies support a proposed mechanistic pathway to elucidate the chain-walking mechanism that determines the controlled branching distribution at varying reaction temperatures. Complex \u003cb\u003eC7\u003c/b\u003e was used to evaluate the efficacy of the carbyl iminopyridyl Ni complexes for copolymerization with polar monomers. These carbyl Ni\u003csup\u003eII\u003c/sup\u003e iminopyridyl complexes are competitive catalysts in which not only the MW but also the branching characteristics can be tuned by cocatalysts and ligand design. In addition, a single catalyst can generate several types of PEs, such as high-density PE (HDPE), low-density PE (LDPE), elastomers, oligomeric waxes, and oils, with different branching densities without the need for copolymerization with α-olefins. This class of complexes is poised to open synthetic alternatives to produce high-performance polyolefins with defined and targeted microstructures, which is uncommon for a onecomplex/onemonomer catalytic system.\u003c/p\u003e "},{"header":"RESULTS AND DISCUSSION","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\n\u003ch2\u003eDesign and Development of Carbyl Iminopyridyl Nickel Catalysts\u003c/h2\u003e\n\u003cp\u003eThe design of the Ni\u003csup\u003eII\u003c/sup\u003e iminopyridyl complexes focused on two aspects. First, the selection of an appropriate carbyl group and second, evaluating a rotational barrier provided by the substituent on the tether carbon between the two iminopyridine donor functions. We chose an \u003cem\u003eo\u003c/em\u003etolyl group as the carbyl substituent, as the aryl ligand has been found to produce benchtopstable bipyridine Ni\u003csup\u003eII\u003c/sup\u003e complexes.\u003csup\u003e21,28\u003c/sup\u003e We hypothesize that the steric bulk of the single \u003cem\u003eN\u003c/em\u003earyl moiety cannot sufficiently contribute to the effective blockage of the metal center to limit chain-transfer. The rotational barrier would restrict the \u003cem\u003eN\u003c/em\u003earyl moiety and its substituents in their mobility, providing more effective axial bulk to limit chain-transfer. The emphasis on the rotational barrier provided by the tether carbon atom was motivated by reports where sterically bulkier \u003cem\u003eortho\u003c/em\u003esubstituents on the \u003cem\u003eN\u003c/em\u003earyl moiety produced lower MW PE.\u003csup\u003e22,23,26\u003c/sup\u003e Only with synthetically demanding half-sandwich ligands can high MW materials be produced.\u003csup\u003e24,25\u003c/sup\u003e This behavior contradicts the established trend reported in late-transition metal complexes where increasing the steric bulk around the metal center produced higher MW materials. In our previous work, we demonstrated that by introducing a \u0026ldquo;rotational barrier\u0026rdquo; \u003cem\u003evia\u003c/em\u003e methyl substituents at the \u003cem\u003emeta\u003c/em\u003e position on the \u003cem\u003eortho\u003c/em\u003e phenyl groups, the geometry of the complex was distorted to more effectively shield the metal center.\u003csup\u003e29\u003c/sup\u003e Therefore, we explore the effect of steric bulk on the tether carbon atom by introducing a phenyl group to serve as an analogous rotational barrier.\u003c/p\u003e\n\u003cp\u003eA series of iminopyridine ligands (\u003cstrong\u003eL1L8\u003c/strong\u003e) were synthesized (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e). Ligands \u003cstrong\u003eL1\u003c/strong\u003e, \u003cstrong\u003eL3\u003c/strong\u003e, \u003cstrong\u003eL5\u003c/strong\u003e, and \u003cstrong\u003eL7\u003c/strong\u003e feature a methyl group on the tether carbon atom and a varied steric bulk on the \u003cem\u003eN\u003c/em\u003earyl moiety, ranging from isopropyl to benzosuberyl groups. Whereas \u003cstrong\u003eL2\u003c/strong\u003e, \u003cstrong\u003eL4\u003c/strong\u003e, \u003cstrong\u003eL6\u003c/strong\u003e, and \u003cstrong\u003eL8\u003c/strong\u003e have a phenyl group on the tether carbon. Ligands \u003cstrong\u003eL1L5\u003c/strong\u003e were prepared according to reported procedures, using a one-step condensation reaction of the aniline with the targeted ketone, and were isolated in high yields (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003csup\u003e23,30\u0026ndash;33\u003c/sup\u003e The more rigid and bulkier \u003cstrong\u003eL6L8\u003c/strong\u003e were designed to further investigate the rotational barrier with sterically bulkier \u003cem\u003eortho\u003c/em\u003esubstituents on the \u003cem\u003eN\u003c/em\u003earyl moiety. The complexations were achieved either by ligand exchange using (PPh\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eNi(\u003cem\u003eo\u003c/em\u003eTol)Cl or by oxidative addition with Ni(COD)\u003csub\u003e2\u003c/sub\u003e and 2chlorotoluene (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003eb), forming iminopyridyl Ni\u003csup\u003eII\u003c/sup\u003e catalysts \u003cstrong\u003eC1C8\u003c/strong\u003e in good yields (66\u0026ndash;92% for \u003cstrong\u003eC1\u003c/strong\u003e-\u003cstrong\u003eC7\u003c/strong\u003e and 10% for \u003cstrong\u003eC8\u003c/strong\u003e, Supplementary Figure S2). Ni\u003csup\u003eII\u003c/sup\u003e complexes \u003cstrong\u003eC1\u003c/strong\u003e-\u003cstrong\u003eC7\u003c/strong\u003e were characterized by \u003csup\u003e1\u003c/sup\u003eH NMR, \u003csup\u003e13\u003c/sup\u003eC NMR, and elemental analysis. In addition, the structures of \u003cstrong\u003eC1\u003c/strong\u003e, \u003cstrong\u003eC3\u003c/strong\u003e, \u003cstrong\u003eC4\u003c/strong\u003e, \u003cstrong\u003eC5\u003c/strong\u003e, \u003cstrong\u003eC7\u003c/strong\u003e, and \u003cstrong\u003eC8\u003c/strong\u003e were determined by singlecrystal Xray diffraction (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003ea), revealing in all cases square planar geometries. The topographic steric maps (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003eb) quantify the steric effect imposed by the ligand on the metal center.\u003csup\u003e34\u003c/sup\u003e Catalysts \u003cstrong\u003eC1\u003c/strong\u003e, \u003cstrong\u003eC3\u003c/strong\u003e, \u003cstrong\u003eC5\u003c/strong\u003e and \u003cstrong\u003eC7\u003c/strong\u003e illustrate the limited steric influence provided by the \u003cem\u003eN\u003c/em\u003earyl moiety on the blockage of the metal center. However, the inclusion of the phenyl group on the tether carbon atom increases the buried volume percentage to 47.0% for \u003cstrong\u003eC4\u003c/strong\u003e and 54.5% for \u003cstrong\u003eC8\u003c/strong\u003e compared to their methyl analogues (45.1% for \u003cstrong\u003eC3\u003c/strong\u003e and 47.6% for \u003cstrong\u003eC7\u003c/strong\u003e). These data support our hypothesis that the substituent on the tether carbon atom can introduce a rotational barrier, enhancing the shielding of the metal center. This is achieved by constraining the rotation of the \u003cem\u003eorthoN\u003c/em\u003e-aryl substituents, thereby imposing greater axial bulk and potentially retarding chain-transfer mechanisms.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\n\u003ch2\u003eCounterion Study\u003c/h2\u003e\n\u003cp\u003eWe selected \u003cstrong\u003eC1\u003c/strong\u003e as a model to study the counterion effect for ethylene polymerization by using various cocatalysts. Preliminary polymerizations with \u003cstrong\u003eC1\u003c/strong\u003e were conducted by \u003cem\u003einsitu\u003c/em\u003e activation with modifiedMAO (MMAO) and diethylaluminum chloride (Et\u003csub\u003e2\u003c/sub\u003eAlCl) at 20\u0026deg;C (Table\u0026nbsp;1, entry 1, 2). The MW of the polymers was analyzed using high-temperature gel permeation chromatography (HTGPC) and was found to be 6.5 and 4.0 kg mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, respectively. Although the organoaluminium cocatalysts produced a highly active species (TOF\u0026thinsp;\u0026gt;\u0026thinsp;535,700 h\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e), the polymerization reaction resulted in a higher dispersity (\u003cem\u003e\u0026ETH;\u003c/em\u003e = 2.47 and 2.11) for the isolated polymers. The \u003cem\u003einsitu\u003c/em\u003e activation of \u003cstrong\u003eC1\u003c/strong\u003e with NaBArF produced PE with higher MW (\u003cem\u003eM\u003c/em\u003e\u003csub\u003en\u003c/sub\u003e = 8.5 kg mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, Table\u0026nbsp;1, entry 3). However, the catalytic activity was poor (TOF\u0026thinsp;=\u0026thinsp;12,900 h\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e). We suggest that the sodium cation is unable to provide a strong driving force to abstract the halide from the metal center, leading to lower productivity. The poor activity was addressed with AgBArF, which produces AgCl that has a greater lattice energy than NaCl, implying a stronger halide scavenger.\u003csup\u003e35\u003c/sup\u003e Activating \u003cstrong\u003eC1\u003c/strong\u003e with AgBArF produced a 12 times more active catalyst (TOF\u0026thinsp;=\u0026thinsp;162,900 h\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e), but reduced the polymer MW to 6.4 kg mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e (Table\u0026nbsp;1, entry 4). Other commonly used cocatalysts, such as NaBF\u003csub\u003e4\u003c/sub\u003e and AgPF\u003csub\u003e6\u003c/sub\u003e, were investigated but were found to produce no polymer, illustrating the significant impact the resulting ionpair has on Ni catalyzed olefin polymerization.\u003c/p\u003e\n\u003cp\u003eTo further enhance catalytic activity, tris(pentafluorophenyl)borane (B(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e) was used as an additive, with previous reports showing that the organoborane promotes ethylene polymerizations with diimine Ni\u003csup\u003eII\u003c/sup\u003e catalysts.\u003csup\u003e19\u003c/sup\u003e Although the sequential addition of both B(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e and AgBArF significantly increased the activity of \u003cstrong\u003eC1\u003c/strong\u003e (TOF = 274,300 h\u003csup\u003e-1\u003c/sup\u003e), the MW of the resulting PE decreased to 4.6 kg mol\u003csup\u003e-1\u003c/sup\u003e (Table 1, entry 5). While the dispersity remained consistent when only using borate cocatalysts, it increased to 2.17 with the addition of B(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e. This increase in dispersity suggested a simultaneous addition of AgBArF and B(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e could generate active species with differing ionpairs. Remarkably, activating \u003cstrong\u003eC1\u003c/strong\u003e with only B(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e produced PE with the highest MW for the tested cocatalysts (\u003cem\u003eM\u003c/em\u003e\u003csub\u003en\u003c/sub\u003e = 11.4 kg mol\u003csup\u003e-1\u003c/sup\u003e) and exhibited good catalytic activity (TOF = 102,900 h\u003csup\u003e-1\u003c/sup\u003e, entry 6).\u003c/p\u003e\n\u003cp\u003eThe difference in catalytic activity between the organoboron cocatalysts can be attributed to the preference in forming either outer or innersphere ionpairs. During polymerization, monomer insertion occurs at the open site of the active catalyst; however this coordination site can be occupied by the cocatalyst.\u003csup\u003e36\u003c/sup\u003e Weakly coordinating anions, such as BArF\u003csup\u003e\u0026minus;\u003c/sup\u003e, should prefer outer-sphere ion-pairs, facilitating monomer coordination and higher catalytic activity.\u003csup\u003e37\u003c/sup\u003e However, this leads to the more \u0026beta;CH agostic species, which can lead to chain-transfer to monomer by \u0026beta;H elimination and lower MWs, as observed experimentally with the activation of \u003cstrong\u003eC1\u003c/strong\u003e with AgBArF. Activation with B(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e produces ClB(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e as the counterion and more favorably lead to inner-sphere ion-pairs, blocking the vacant coordination site and competing with monomer coordination and the formation of \u0026beta;CH agostic species.\u003csup\u003e38,39\u003c/sup\u003e This innersphere coordination would reduce the overall catalytic activity, but would also lead to a lower impact of chaintransfer reactions and to higher MW polymers,\u003csup\u003e40\u003c/sup\u003e as observed with the activation of \u003cstrong\u003eC1\u003c/strong\u003e with B(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e. This study suggests that the use of B(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e for Ni-catalyzed ethylene polymerization has a profound influence on the chainpropagation to access high MW polymers \u003cem\u003evia\u003c/em\u003e an inner-sphere ionpair interactions.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\n\u003ch2\u003eDFT Calculations for Counterion Study\u003c/h2\u003e\n\u003cp\u003eTo validate the above proposition of a stronger inner-sphere action for the ClB(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e anion in this Ni system, a computational investigation was conducted. The DFT calculations aimed at elucidating the structural and energetic differences in the interaction of the cationic nickel catalyst with the BArF\u003csup\u003e\u0026minus;\u003c/sup\u003e and ClB(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e. The cation ligand was simplified to the unsubstituted pyridine-imine, NC\u003csub\u003e5\u003c/sub\u003eH\u003csub\u003e4\u003c/sub\u003e-2CH\u0026thinsp;=\u0026thinsp;NH, and the PE chain was truncated to a propyl group, generated by insertion of an ethylene molecule into the NiCH\u003csub\u003e3\u003c/sub\u003e bond. For the anion, the full system was used. The geometry optimizations were conducted in the presence of a polarizable continuum with the permittivity of dichloromethane and thermal corrections were applied to obtain standard Gibbs energy values in condensed medium (298 K, 1 mole/L).\u003c/p\u003e\n\u003cp\u003eThe cation-anion interaction was investigated only for the most stable NiPr isomer, namely the \u0026beta;agostic complex with the propyl group \u003cem\u003etrans\u003c/em\u003e to the pyridine ring (Supplementary Figure S140). For both anions, the addition with displacement of the \u0026beta;agostic CH ligand is exoergic, with a stabilization comparable to that of the coordination of the next ethylene molecule needed for propagation (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e). The addition of ethylene lowers the Gibbs energy of the system by -12.8 kcal mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, whereas the anion coordination lowers it by -12.1 kcal mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e for BArF\u003csup\u003e\u0026minus;\u003c/sup\u003e and by -13.2 kcal mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e for ClB(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e. The greater stabilization associated to the ClB(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e coordination is obviously related to the greater donor power of the Cl lone pair in the BCl bond, relative to the F lone pair in the CF bond of the BArF\u003csup\u003e\u0026minus;\u003c/sup\u003e anion. The latter, however, is also surprisingly efficient, demystifying the concept that BArF\u003csup\u003e\u0026minus;\u003c/sup\u003e is a non-coordinating anion.\u003csup\u003e12\u003c/sup\u003e\u003c/p\u003e\n\u003cp\u003eIn the structure of the [Ni(NC\u003csub\u003e5\u003c/sub\u003eH\u003csub\u003e4\u003c/sub\u003eCHNH)(Pr)]\u003csup\u003e+\u003c/sup\u003eClB(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus; 41\u003c/sup\u003e adduct, the NiCl distance (2.250 \u0026Aring;) is a bit longer than in the optimized [Ni(NC\u003csub\u003e5\u003c/sub\u003eH\u003csub\u003e4\u003c/sub\u003eCHNH)(Pr)Cl] complex (2.225 \u0026Aring;, a lengthening by only 0.025 \u0026Aring;), but the BCl distance (2.255 \u0026Aring;) is much longer than in the free ClB(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e anion (2.003 \u0026Aring;, a lengthening by 0.252 \u0026Aring;). Furthermore, the B atom is pyramidalized (sum of the three CBC angles\u0026thinsp;=\u0026thinsp;350.7\u0026deg;) to a much lesser extent than in the free ClB(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e anion (340.8\u0026deg;), whereas the neutral B(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e Lewis acid has a planar B atom (360\u0026deg;). These structural parameters suggest that the NiClB bonding is better considered as a weak dative interaction from the Cl ligand in the neutral [Ni(NC\u003csub\u003e5\u003c/sub\u003eH\u003csub\u003e4\u003c/sub\u003eCHNH)(Pr)Cl] complex to the B atom in the B(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e Lewis acid (Ni-Cl\u0026loz;B), rather than as a Ni\u0026dArr;Cl-B dative interaction from the ClB(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e anion to the [Ni(NC\u003csub\u003e5\u003c/sub\u003eH\u003csub\u003e4\u003c/sub\u003eCHNH)(Pr)]\u003csup\u003e+\u003c/sup\u003e cation. The Gibbs energy of the [Ni(NC\u003csub\u003e5\u003c/sub\u003eH\u003csub\u003e4\u003c/sub\u003eCHNH)(Pr)Cl]\u0026thinsp;+\u0026thinsp;B(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e system is -12.2 kcal mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e relative to the \u0026beta;agostic [Ni(NC\u003csub\u003e5\u003c/sub\u003eH\u003csub\u003e4\u003c/sub\u003eCHNH)(Pr)]\u003csup\u003e+\u003c/sup\u003e cation\u0026thinsp;+\u0026thinsp;ClB(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e anion, namely only\u0026thinsp;+\u0026thinsp;1.0 kcal mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e relative to the inner-sphere ion-pair. Thus, according to these calculations, the Lewis acidbase interaction between [Ni(NC\u003csub\u003e5\u003c/sub\u003eH\u003csub\u003e4\u003c/sub\u003eCHNH)(Pr)Cl] and B(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e is weak but can furnish the \u0026beta;agostic alkyl complex as a kinetically competent intermediate and then the ethylene adduct rather easily. In the structure of the innersphere [Ni(NC\u003csub\u003e5\u003c/sub\u003eH\u003csub\u003e4\u003c/sub\u003eCHNH)(Pr)]\u003csup\u003e+\u003c/sup\u003eBArF\u003csup\u003e\u0026minus;\u003c/sup\u003e ionpair, the NiF distance is 2.082 \u0026Aring; and the CF distance of the Nicoordinated CF bond is 1.432 \u0026Aring;, whereas all other noninteracting CF bonds have distances in the 1.35\u0026ndash;1.36 \u0026Aring; range, attesting the non-negligible effect of the F\u0026loz;Ni interaction on the CF bond.\u003c/p\u003e\n\u003cp\u003eIn conclusion, the B(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e Lewis acid is able to activate the NiCl bond to remove the chloride ion from the nickel coordination sphere, but the cation interaction with ClB(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e competes more efficiently with the ethylene coordination than the interaction with the BArF\u003csup\u003e\u0026minus;\u003c/sup\u003e anion, although the latter anion is not such a weakly coordinating one in this system. The inner-sphere [Ni(NC\u003csub\u003e5\u003c/sub\u003eH\u003csub\u003e4\u003c/sub\u003eCHNH)(Pr)]\u003csup\u003e+\u003c/sup\u003eClB(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;41\u003c/sup\u003e ion-pair, better described as a [Ni(NC\u003csub\u003e5\u003c/sub\u003eH\u003csub\u003e4\u003c/sub\u003eCHNH)(Pr)(Cl)]⸱⸱⸱B(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e Lewis acid-base adduct, is predicted to be the resting state of the propagation process, rather than the outer-sphere [Ni(NC\u003csub\u003e5\u003c/sub\u003eH\u003csub\u003e4\u003c/sub\u003eCHNH)(Pr)(C\u003csub\u003e2\u003c/sub\u003eH\u003csub\u003e4\u003c/sub\u003e)]\u003csup\u003e+\u003c/sup\u003eClB(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e ionpair, and the energy span of the propagation process is marginally greater, resulting in a slower polymerization.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\n\u003ch2\u003eEthylene Polymerization Study with C1C8 at 20\u0026deg;C\u003c/h2\u003e\n\u003cp\u003eSince B(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e has been found to be an exceptional activator for this system, and yielding higher MW materials, we sought to investigate the substituent effect using B(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e for all iminopyridyl complexes. Ethylene polymerizations were conducted at 20\u0026deg;C with 400 psi of ethylene pressure, yielding the results summarized in Table\u0026nbsp;2. Complexes with the methyl group on the tether carbon atom (\u003cstrong\u003eC1\u003c/strong\u003e, \u003cstrong\u003eC3\u003c/strong\u003e, \u003cstrong\u003eC5\u003c/strong\u003e, and \u003cstrong\u003eC7\u003c/strong\u003e) highlight the effect of increasing the steric bulk on the \u003cem\u003eN\u003c/em\u003earyl moiety. No significant difference in MWs was observed for the polymers produced by \u003cstrong\u003eC1\u003c/strong\u003e, \u003cstrong\u003eC3\u003c/strong\u003e and \u003cstrong\u003eC5\u003c/strong\u003e (\u003cem\u003eM\u003c/em\u003e\u003csub\u003en\u003c/sub\u003e = 11.4, 7.8, and 11.7 kg mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e), attesting to the limited effect of steric bulk towards the blockage of the metal center, in line with the marginal increase of the calculated \u003cem\u003eV\u003c/em\u003e\u003csub\u003e\u003cem\u003eBur\u003c/em\u003e\u003c/sub\u003e%. Although the \u003cem\u003eV\u003c/em\u003e\u003csub\u003e\u003cem\u003eBur\u003c/em\u003e\u003c/sub\u003e% increases to only 47.6% in \u003cstrong\u003eC7\u003c/strong\u003e, the polymers produced have the highest MWs of the methyl bridging series (\u003cem\u003eM\u003c/em\u003e\u003csub\u003en\u003c/sub\u003e = 153.7 kg mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) with lower dispersity (\u003cem\u003e\u0026ETH;\u003c/em\u003e = 1.77) at 20\u0026deg;C. This is over 10 times higher than any previously tested complex with a methyl-substituted carbon tether and 5 times higher than similar catalysts activated with organoaluminum (Table\u0026nbsp;2, entry 4).\u003csup\u003e42\u003c/sup\u003e The data suggests that the benzosuberyl ligand provides a rigid steric environment that is a consequence of restricted rotation and further supports the hypothesis that higher MW materials can also be achieved with a more rigid ligand design.\u003c/p\u003e\n\u003cp\u003eComplexes with the phenyl group on the bridging carbon (\u003cstrong\u003eC2\u003c/strong\u003e, \u003cstrong\u003eC4\u003c/strong\u003e, \u003cstrong\u003eC6\u003c/strong\u003e, and \u003cstrong\u003eC8\u003c/strong\u003e) should increase the rotational restriction of the \u003cem\u003eN\u003c/em\u003e-aryl substituents. \u003cstrong\u003eC2\u003c/strong\u003e exhibited low catalytic activity (TOF\u0026thinsp;=\u0026thinsp;10,700 h\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) and the resulting PE (\u003cem\u003eM\u003c/em\u003e\u003csub\u003en\u003c/sub\u003e = 6.9 kg mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) was lower in MW compared with \u003cstrong\u003eC1\u003c/strong\u003e. Surprisingly, \u003cstrong\u003eC4\u003c/strong\u003e exhibited a completely different result and was able to produce PE with MW more than triple compared to \u003cstrong\u003eC3\u003c/strong\u003e (\u003cem\u003eM\u003c/em\u003e\u003csub\u003en\u003c/sub\u003e = 23.8 kg mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) (Table\u0026nbsp;2, entry 6). The polymerization results of \u003cstrong\u003eC4\u003c/strong\u003e supported our hypothesis that the phenyl substituent on the tether carbon atom acts as a rotational barrier and is key for producing higher MW polymers. As for \u003cstrong\u003eC2\u003c/strong\u003e, the isopropyl group is not bulky enough even with the phenyl group acting as a rotational barrier, thus resulting in low MW PEs. Similar to \u003cstrong\u003eC4\u003c/strong\u003e, \u003cstrong\u003eC6\u003c/strong\u003e produced much higher MW PE (\u003cem\u003eM\u003c/em\u003e\u003csub\u003en\u003c/sub\u003e = 37.0 kg mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) with lower dispersity (Table\u0026nbsp;2, entry 7). This confirmed our hypothesis, where the \u003cem\u003emeta\u003c/em\u003emethyl substituents introduced to the benzhydryl groups, alongside the tether carbon rotational barrier, provided higher shielding for the metal center. Synthetic challenges in preparing pure and isomer-free ligands, low complexation, and turnover yields, identified \u003cstrong\u003eC8\u003c/strong\u003e as a complex with undesirable properties. The data suggest that the polymer MW cannot be directly governed by the axial steric environment provided by the \u003cem\u003eortho\u003c/em\u003esubstituents of the \u003cem\u003eN\u003c/em\u003earyl moiety. Moreso, emphasis on the design of ligands with a rotational barrier provided by the tether carbon atom substituent may be more effective at producing higher MW polymers.\u003c/p\u003e\n\u003cp\u003eTo confirm the thermal stability of the carbyl complexes, \u003cstrong\u003eC1\u003c/strong\u003e was assessed at reaction temperatures ranging from 0-80 \u0026deg;C. The complex is still highly active in polymerization reactions up to 60 \u0026deg;C, which is indicative of good thermal stability (TOF = 94,300 h\u003csup\u003e-1\u003c/sup\u003e). However, at 80 \u0026deg;C, the activity dramatically decreases to 30,000 h\u003csup\u003e-1\u003c/sup\u003e which suggests catalyst degradation. We observed that the MW of PEs from \u003cstrong\u003eC1\u003c/strong\u003e is highly dependent on the reaction temperature. With decreasing temperatures, the MW of PEs increased to 65.1 kg mol\u003csup\u003e-1\u003c/sup\u003e at 0 \u0026deg;C (Table 3, entry 1). Only oligomers were generated at temperatures above 40 \u0026deg;C (Table 3, entry 4, 5). A similar trend was observed in the iminopyridyl Ni\u003csup\u003eII\u003c/sup\u003e catalysts \u003cstrong\u003eC2C7\u003c/strong\u003e, with \u003cstrong\u003eC4\u003c/strong\u003e producing high MW polymers at 0 \u0026deg;C (\u003cem\u003eM\u003c/em\u003e\u003csub\u003en\u003c/sub\u003e = 164.6 kg mol\u003csup\u003e-1\u003c/sup\u003e) and 5.6 kg mol\u003csup\u003e-1\u003c/sup\u003e at 60 \u0026deg;C with the addition of the rotational barrier provided by the tether carbon (Supplementary Table \u003cspan class=\"InternalRef\"\u003eS1\u003c/span\u003e).\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\n\u003ch2\u003eCopolymerization\u003c/h2\u003e\n\u003cp\u003eCopolymerizations with iminopyridyl Ni\u003csup\u003eII\u003c/sup\u003e catalysts have been reported to be challenging, where both a high incorporation of polar monomer and high MW PE cannot be synthesized.\u003csup\u003e43-45\u003c/sup\u003e We selected \u003cstrong\u003eC7 \u003c/strong\u003eas the model for producing copolymers (Table 4). Interestingly, \u003cstrong\u003eC7\u003c/strong\u003e produced methyl acrylate (MA) copolymers with good incorporation (2.2 mol%) and moderate MW (35.8 kg\u0026nbsp;mol\u003csup\u003e-1\u003c/sup\u003e). Additionally, we tested vinyltriethoxysilane (VTEoS) and vinyl acetate (VAc) which have never been reported as comonomers for iminopyridyl Ni\u003csup\u003eII\u003c/sup\u003e complexes. Copolymers with about 6 mol% VTEoS incorporation and MWs of 48.1\u0026nbsp;kg\u0026nbsp;mol\u003csup\u003e-1\u003c/sup\u003e were produced and targeting higher MW copolymers (66.3 kg\u0026nbsp;mol\u003csup\u003e-1\u003c/sup\u003e) lowered the incorporation to 3 mol%. For copolymers with VAc, \u003cstrong\u003eC7\u003c/strong\u003e produced polymers with MWs of 53.3 kg\u0026nbsp;mol\u003csup\u003e-1\u003c/sup\u003e and incorporation of 0.26 mol%. In general, AgBArF performed better as a cocatalyst for copolymerization over B(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e. These data further support the claim that the unique interaction of the inner-sphere organoboron counterion competes with the polar monomer coordination.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\n\u003ch2\u003eBranching Density and Distribution\u003c/h2\u003e\n\u003cp\u003eSurprisingly, the branching density of PEs obtained from \u003cstrong\u003eC1\u003c/strong\u003e exhibited a linear relationship with respect to the reaction temperature under high pressure conditions where chainwalking should be suppressed (Supplementary Figure \u003cspan class=\"InternalRef\"\u003eS1\u003c/span\u003e).\u003csup\u003e46\u003c/sup\u003e The control over the branching density ranges from 5 branches/1000 carbon atoms at 0\u0026deg;C to 127 branches/1000 carbon atoms at 80\u0026deg;C and a similar linear branching regulation was observed with complexes \u003cstrong\u003eC2\u003c/strong\u003e-\u003cstrong\u003eC7\u003c/strong\u003e in the same reaction temperature range. For example, \u003cstrong\u003eC4\u003c/strong\u003e ranged from 18 branches/1000 carbon atoms at 0\u0026deg;C to 104 branches/1000 carbon atoms at 60\u0026deg;C. This data suggests that the branching density could be precisely controlled by temperature with the carbyl iminopyridyl Ni\u003csup\u003eII\u003c/sup\u003e system. Compared to half-sandwich iminopyridyl Ni\u003csup\u003eII\u003c/sup\u003e complexes, the branching density is limited to a range of 79 branches/1000 carbon atoms at 25\u0026deg;C to 125 branches/1000 carbon atoms at 70\u0026deg;C.\u003csup\u003e47\u003c/sup\u003e We suggest that the unique control of the branching density exhibited by the carbyl Ni\u003csup\u003eII\u003c/sup\u003e complexes is influenced by the iminopyridine ligand in combination with the innersphere organoboron/Ni ionpair.\u003c/p\u003e\n\u003cp\u003eThe ability to produce a wide range of branching densities resulted in the production of diverse materials and prompted further investigation into their unique microstructures. \u003csup\u003e1\u003c/sup\u003eH NMR and differential scanning calorimetry (DSC) showed that the PEs obtained from \u003cstrong\u003eC1\u003c/strong\u003e at 0\u0026deg;C had only 5 branches/1000 carbon atoms and a \u003cem\u003eT\u003c/em\u003e\u003csub\u003em\u003c/sub\u003e of 127.8\u0026deg;C, classifying the polymer as HDPE. At 20\u0026deg;C, the branching density increased to 25 branches/1000 carbon atoms and a decrease in \u003cem\u003eT\u003c/em\u003e\u003csub\u003em\u003c/sub\u003e to 108.6\u0026deg;C, producing LDPE. Minor elastomeric properties were observed from the PE obtained at 40\u0026deg;C, with a branching density of 56 branches/1000 carbon atoms and a \u003cem\u003eT\u003c/em\u003e\u003csub\u003em\u003c/sub\u003e of 64.4\u0026deg;C. Wax-like materials were generated at 60\u0026deg;C and a branching density of 95 branches/1000 carbon atoms and a \u003cem\u003eT\u003c/em\u003e\u003csub\u003em\u003c/sub\u003e of 9.3\u0026deg;C, and an oligomeric oil was formed at 80\u0026deg;C with a sub-zero \u003cem\u003eT\u003c/em\u003e\u003csub\u003em\u003c/sub\u003e (Table\u0026nbsp;3, entries 1\u0026ndash;5). In summary, a single catalyst can produce several types of PEs with broad branching densities. This versatility is achieved without the need for expensive comonomers, making it highly desirable in polyolefin syntheses and processes. We point out that it is unusual for these complexes to produce a wide variety of PE at high pressures, where chainwalking should be retarded.\u003c/p\u003e\n\u003cp\u003eThe material properties of the PE produced by organoboron activated complexes suggest a unique branching microstructure commonly achieved through \u0026alpha;olefin copolymerization, which introduces shortchain branches (SCBs). It has been understood that the controlled incorporation of SCBs, where the branch length is 5 carbon atoms or less, can dramatically impact the mechanical properties of PE.\u003csup\u003e48,49\u003c/sup\u003e Therefore, the analysis of the branching microstructure of polymers produced by \u003cstrong\u003eC1\u003c/strong\u003e under high ethylene pressure was conducted using quantitative \u003csup\u003e13\u003c/sup\u003eC NMR spectroscopy (Supplementary Figures S58-63) and is included in Table 3.\u003csup\u003e50,51\u003c/sup\u003e At 0 \u0026deg;C, only methyl branches are observed. Increasing the temperature to 20 \u0026deg;C induces the incorporation of ethyl, propyl, and a large percentile of long-chain branches (LCBs). Additional ethyl and propyl branches were observed in the polymer at 40 \u0026deg;C, with new butyl and amyl branches being detected. At 60 and 80 \u0026deg;C, all SCBs were incorporated and increased for amyl and LCBs at the expense of methyl branches. Current iminechelated Ni\u003csup\u003eII\u003c/sup\u003e complexes must utilize low pressure conditions and/or elaborate ligand designs to promote chainwalking and tailor the polymer microstructure.\u003csup\u003e52-54\u003c/sup\u003e However, this strategy is not effective as the incorporation of SCBs is negligible. Since our system produces shortchain branches under high pressure conditions and is not supported by established mechanistic understandings, we sought to further investigate the underlying chainwalking mechanism through computational studies. Therefore, additional DFT calculations were conducted for \u003cstrong\u003eC1\u003c/strong\u003e with respect to temperatures ranging from 0 to 80 \u0026deg;C.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e\n\u003ch2\u003eDFT Calculations for ChainWalking Mechanism\u003c/h2\u003e\n\u003cp\u003eThe polymerization is modeled from the \u0026beta;CH agostic species, the resting state, with a propagating polymer chain \u003cstrong\u003e1\u003c/strong\u003e (Supplementary Figure S141) and can proceed through two pathways (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003ea). The free energy profile at 60\u0026deg;C is used as a representative data set to discuss the branching distribution and energy profile (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003eb). The remaining free energy profiles for the tested temperature range are included as Supplementary Figures S142-145. The first pathway is a coordination/insertion of ethylene to produce a linear polymer (\u003cstrong\u003eLinear\u003c/strong\u003e). Monomer coordination must overcome a free energy barrier (\u003cstrong\u003eTS\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e1MC\u003c/strong\u003e\u003c/sub\u003e) of 16.3 kcal mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e and is exergonic by 3.9 kcal mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. Alternatively, the agostic species \u003cstrong\u003e1\u003c/strong\u003e can undergo \u0026beta;hydride elimination (\u003cstrong\u003eTS\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e2BHE\u003c/strong\u003e\u003c/sub\u003e) to form the olefin \u0026pi; complex \u003cstrong\u003e2\u003c/strong\u003e with an energy barrier of 12.2 kcal mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. Complex \u003cstrong\u003e2\u003c/strong\u003e then can undergo 2,1reinsertion (\u003cstrong\u003eTS\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e23RI\u003c/strong\u003e\u003c/sub\u003e), with an energy barrier of 5.1 kcal mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e and generate the new \u0026beta;CH agostic species \u003cstrong\u003e3\u003c/strong\u003e. This process is exergonic by -12.6 kcal mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e and is favored over direct ethylene coordination insertion by 4.7 kcal mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. The agostic species \u003cstrong\u003e3\u003c/strong\u003e can again either undergo monomer coordination (\u003cstrong\u003eTS\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e3MC\u003c/strong\u003e\u003c/sub\u003e) with an energy barrier of 8.1 kcal mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e to produce a methyl branch (\u003cstrong\u003eMethyl\u003c/strong\u003e) or \u0026beta;hydride elimination (\u003cstrong\u003eTS\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e4BHE\u003c/strong\u003e\u003c/sub\u003e) for further chainwalking. However, the 13.0 kcal mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e energy barrier for chain-walking suggests that methyl branch formation is more favorable, consistent with the predominant branch experimentally observed at all temperatures. Once the agostic species \u003cstrong\u003e3\u003c/strong\u003e crosses the barrier \u003cstrong\u003eTS\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e4BHE\u003c/strong\u003e\u003c/sub\u003e, the olefin \u0026pi; complex \u003cstrong\u003e4\u003c/strong\u003e is formed and can undergo 3,2reinsertion (\u003cstrong\u003eTS\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e45RI\u003c/strong\u003e\u003c/sub\u003e), with a minimal barrier of only 3.0 kcal mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, to form \u0026beta;CH agostic complex \u003cstrong\u003e5\u003c/strong\u003e in an exergonic step (-6.1 kcal mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e). After the formation of complex \u003cstrong\u003e5\u003c/strong\u003e, \u0026beta;elimination must overcome a barrier of 23.2 kcal mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e (\u003cstrong\u003eTS\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e6BHE\u003c/strong\u003e\u003c/sub\u003e). The significantly lower barrier of 5.2 kcal mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e (\u003cstrong\u003eTS\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e5MC\u003c/strong\u003e\u003c/sub\u003e) for ethylene insertion to produce ethyl branched (\u003cstrong\u003eEthyl\u003c/strong\u003e) polymer in a mildly exergonic step (-0.3 kcal mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) agrees well with the measured formation of ethyl branches starting from 20\u0026deg;C in our experiments.\u003c/p\u003e\n\u003cp\u003eFollowing \u0026beta;elimination from complex \u003cstrong\u003e5\u003c/strong\u003e, the further reinsertion step is barrierless for all studied temperatures and favors the spontaneous formation of \u0026beta;CH agostic complex \u003cstrong\u003e7\u003c/strong\u003e. The overall chainwalking step from \u003cstrong\u003e5\u003c/strong\u003e to \u003cstrong\u003e7\u003c/strong\u003e is endergonic by 5.3 kcal mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. From complex \u003cstrong\u003e7\u003c/strong\u003e the barrier for propyl branch formation (\u003cstrong\u003eTS\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e7MC\u003c/strong\u003e\u003c/sub\u003e) is 6.5 kcal mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003eand is marginally lower than the barrier of 9.2 kcal mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e (\u003cstrong\u003eTS\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e8BHE\u003c/strong\u003e\u003c/sub\u003e) for \u0026beta;elimination leading to \u003cstrong\u003e8\u003c/strong\u003e and its spontaneous conversion to \u003cstrong\u003e9\u003c/strong\u003e at temperatures above 40\u0026deg;C. Next, \u0026beta;elimination to olefin \u0026pi; complex \u003cstrong\u003e10\u003c/strong\u003e, followed by the 6,5reinsertion to \u0026beta;CH agostic complex \u003cstrong\u003e11\u003c/strong\u003e is the precursor to form amyl branches. The \u0026beta;elimination step is endergonic by 13.0 kcal mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003ewith a barrier of 16.6 kcal mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e (\u003cstrong\u003eTS\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e10BHE\u003c/strong\u003e\u003c/sub\u003e), but the reinsertion step is thermodynamically favorable and is exergonic. Although the calculated activation barrier value of 22.3 kcal mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e for reinsertion (\u003cstrong\u003eTS\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e1011RI\u003c/strong\u003e\u003c/sub\u003e) suggests a low amount of amyl branches, reactions above 40\u0026deg;C have moderate percent incorporation (Table\u0026nbsp;3, entries 3\u0026ndash;5). The percentage of amyl and LCBs produced can be attributed to the mechanism proposed by Wu and coworkers, where the Ni complex chainwalks to a terminal position on an existing methyl branch, forming a new primary Nialkyl species together with a longchain branch, which can include amyl.\u003csup\u003e52\u003c/sup\u003e\u003c/p\u003e\n\u003cp\u003eTo rationalize the observed trends in branching behavior with temperature, we have calculated the free energy changes of relevant intermediate and transition states for chain-walking between 0 and 80\u0026deg;C. Figure\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e shows that free energies decrease with increasing temperature, except for \u003cstrong\u003eTS\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e6BHE\u003c/strong\u003e\u003c/sub\u003e, \u003cstrong\u003e7\u003c/strong\u003e, and \u003cstrong\u003e8\u003c/strong\u003e, which show minor destabilization with temperature. Thus, higher temperatures should favor the gradual incorporation of longer branches, which is consistent with the branching distribution reported in Table\u0026nbsp;3. While the barrier associated with \u003cstrong\u003e8\u003c/strong\u003e increases by less than 0.2 kcal mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e from 0\u0026ndash;80\u0026deg;C, the increase in thermal energy (\u003cem\u003ek\u003c/em\u003e\u003csub\u003e\u003cem\u003eb\u003c/em\u003e\u003c/sub\u003e\u003cem\u003eT\u003c/em\u003e) allows the reaction to proceed at elevated temperatures. This also agrees well with the experimental observation of butyl branches starting at 40\u0026deg;C, which is the first branched product after \u003cstrong\u003e8\u003c/strong\u003e.\u003c/p\u003e\n\u003cp\u003eHere, a new class of bench-top iminopyridyl Ni\u003csup\u003eII\u003c/sup\u003e complexes were prepared with an \u003cem\u003eo\u003c/em\u003e-tolyl carbyl substituents which enables an investigation of the effect of inner- and outer-sphere ion-pairs for olefin polymerization. Earlytransition metal complexes demonstrate the importance of the counterion controlling polyolefin microstructures, but the influence and impact of counterion effects in late transition complexes, specifically for imine-chelated Ni\u003csup\u003eII\u003c/sup\u003e complexes have been largely unexplored, due to the absence of a suitable thermodynamically stable complex. We demonstrated that with well-defined, inner-sphere ClB(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e counterion leads to higher MW materials and the possibility for controlled short-chain branch incorporation utilizing increasing reaction temperatures. This led to materials with properties comparable to HDPE, LDPE, elastomers, waxes, and oils. Additionally, we showed that the substituents on the tether carbon can act as a rotational barrier imposing more axial bulk around the metal center and favor chain-propagation. This highlights the importance of substituent placement on the tether carbon moiety, instead of the more traditional ligand design focusing on the aryl imine. We anticipate that this study will invigorate the exploration of inner-sphere counterions with the extensive iminopyridine ligand catalog for the synthesis of high value polyolefins with unique branching characteristics and properties.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"METHODS","content":"\u003cp\u003eAll manipulations of air- and water-sensitive compounds were conducted under an inert atmosphere using glovebox, Schlenk and high-vacuum techniques, unless otherwise noted. Deuterated solvents were purchased from Cambridge isotopes and used as received. \u003csup\u003e1\u003c/sup\u003eH and \u003csup\u003e13\u003c/sup\u003eC NMR were acquired on JEOL JNMECA 400 (400 MHz), JNMECZ400S (400 MHz), or ECA-600 (600 MHz) spectrometers. Chemical shifts are measured relative to residual solvent peaks as an internal standard set to \u0026delta; 7.26 and \u0026delta; 77.16 (chloroform-\u003cem\u003ed\u003c/em\u003e\u003csub\u003e\u003cem\u003e1\u003c/em\u003e\u003c/sub\u003e (CDCl\u003csub\u003e3\u003c/sub\u003e)), \u0026delta; 5.32 and \u0026delta; 53.84 (methylene chlorided\u003csub\u003e2\u003c/sub\u003e (CD\u003csub\u003e2\u003c/sub\u003eCl\u003csub\u003e2\u003c/sub\u003e)) and \u0026delta; 6.00 and \u0026delta; 73.78 (1,1,2,2tetrachloroethaned\u003csub\u003e2\u003c/sub\u003e (C\u003csub\u003e2\u003c/sub\u003eD\u003csub\u003e2\u003c/sub\u003eCl\u003csub\u003e4\u003c/sub\u003e,)) for \u003csup\u003e1\u003c/sup\u003eH and \u003csup\u003e13\u003c/sup\u003eC, respectively. Quantitative \u003csup\u003e13\u003c/sup\u003eC NMR spectra of polymers were recorded on the ECA-600 (600 MHz) spectrometer at 125\u0026deg;C, in C\u003csub\u003e2\u003c/sub\u003eD\u003csub\u003e2\u003c/sub\u003eCl\u003csub\u003e4\u003c/sub\u003e with Cr(acac)\u003csub\u003e3\u003c/sub\u003e as a relaxation agent (0.05 M). Electrospray ionization mass spectrometry (ESIMS) experiments were performed using a Thermo Scientific Q Exactive Focus instrument by the Mass Spectrometry Facility at Texas A\u0026amp;M in College Station, Texas. Gel Permeation Chromatography (GPC) was performed using a Tosoh EcoSEC HLC-8321 GPC/HT system equipped with an autosampler, three TSKgel GMHhrH(S) HT2 columns, builtin dual flow refractive index (RI) detector, and viscometer. GPC analyses were conducted in HPLC grade 1,2,4trichlorobenzene with a flow rate of 1.0 mL/min at 160\u0026deg;C calibrated with polystyrene standards. The elemental analyses were performed by Atlantic Microlab, lnc. in Norcross, Georgia. Differential Scanning Calorimetry (DSC) investigations were conducted on a TA Instruments DSC 2500 system. The samples were heated from 25\u0026deg;C to 180\u0026deg;C, cooled to \u0026minus;\u0026thinsp;90\u0026deg;C, and then heated to 180\u0026deg;C at a rate of 10\u0026deg;C/minute. DSC data were obtained from the second heating cycle. The polymer branching density and distribution were calculated using established proton and carbon NMR signals.\u003csup\u003e51\u003c/sup\u003e\u003c/p\u003e\n\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\n\u003ch2\u003eSynthesis of iminopyridyl Ni\u003csup\u003eII\u003c/sup\u003e complexes C1-C8\u003c/h2\u003e\n\u003cp\u003eFor \u003cstrong\u003eC1\u003c/strong\u003e, \u003cstrong\u003eC3\u003c/strong\u003e, \u003cstrong\u003eC5\u003c/strong\u003e, \u003cstrong\u003eC7\u003c/strong\u003e, and \u003cstrong\u003eC8\u003c/strong\u003e: To a dried 100 mL round-bottomed flask filled with nitrogen was added (PPh\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eNi(\u003cem\u003eo\u003c/em\u003e-tol)Cl (500 mg, 0.7 mmol) and 0.77 mmol of the corresponding iminopyridine ligand. Toluene (20 mL) was injected into the reaction and stirred at room temperature. The red/purple suspensions were formed after stirring for 16 hours. 10 mL of pentane was added to the reaction, and the precipitate was filtered and collected. The catalyst was dissolved in DCM and filtered through celite. The filtrate was concentrated under vacuum, and the resulting product was purified \u003cem\u003evia\u003c/em\u003e recrystallization from dichloromethane and pentane.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eC1\u003c/strong\u003e: Anal. Calcd. for C\u003csub\u003e26\u003c/sub\u003eH\u003csub\u003e31\u003c/sub\u003eClN\u003csub\u003e2\u003c/sub\u003eNi: C, 67.06; H, 6.71; N, 6.02; Found: C, 67.12; H, 6.76; N, 5.94.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eC2\u003c/strong\u003e: Anal. Calcd. for C\u003csub\u003e31\u003c/sub\u003eH\u003csub\u003e33\u003c/sub\u003eClN\u003csub\u003e2\u003c/sub\u003eNi: C, 70.55; H, 6.30; N, 5.31; Found: C, 70.42; H, 6.27; N, 5.25.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eC3\u003c/strong\u003e: Anal. Calcd for C\u003csub\u003e47\u003c/sub\u003eH\u003csub\u003e41\u003c/sub\u003eClN\u003csub\u003e2\u003c/sub\u003eNi: C, 77.54; H, 5.68; N, 3.85. Found: C, 77.19; H, 5.66; N, 3.87.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eC5\u003c/strong\u003e: Anal. Calcd for C\u003csub\u003e55\u003c/sub\u003eH\u003csub\u003e57\u003c/sub\u003eClN\u003csub\u003e2\u003c/sub\u003eNi: C, 78.62; H, 6.84; N, 3.33. Found: C, 78.61; H, 6.79; N, 3.31.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eC7\u003c/strong\u003e: Anal. Calcd for C\u003csub\u003e51\u003c/sub\u003eH\u003csub\u003e45\u003c/sub\u003eClN\u003csub\u003e2\u003c/sub\u003eNi: C, 78.53; H, 5.81; N, 3.59. Found: C, 78.25; H, 5.72; N, 3.48.\u003c/p\u003e\n\u003cp\u003eFor \u003cstrong\u003eC4\u003c/strong\u003e and \u003cstrong\u003eC6\u003c/strong\u003e: To a flame-dried 100 mL round-bottomed flask filled with nitrogen was added Ni(COD)\u003csub\u003e2\u003c/sub\u003e (137.5 mg, 0.5 mmol) and 0.5 mmol of the corresponding iminopyridine ligand. 2-chlorotoluene (4 mL) was injected into the reaction and stirred at room temperature. The purple suspensions were formed after stirring for 16 hours. The reaction was diluted with DCM and then filtered through celite. The filtrate was concentrated, and the resulting product was purified \u003cem\u003evia\u003c/em\u003e recrystallization from chloroform and pentane.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eC4\u003c/strong\u003e: Anal. Calcd for C\u003csub\u003e52\u003c/sub\u003eH\u003csub\u003e43\u003c/sub\u003eClN\u003csub\u003e2\u003c/sub\u003eNi: C, 79.05; H, 5.49; N, 3.55. Found: C, 78.88; H, 5.52; N, 3.51.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eC6\u003c/strong\u003e: Anal. Calcd for C\u003csub\u003e60\u003c/sub\u003eH\u003csub\u003e59\u003c/sub\u003eClN\u003csub\u003e2\u003c/sub\u003eNi: C, 79.87; H, 6.59; N, 3.10. Found: C, 79.60; H, 6.50; N, 3.10.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e\n\u003ch2\u003eGeneral Procedure for ethylene homo- and co-polymerization\u003c/h2\u003e\n\u003cp\u003eA 300 mL Series 5521 Compact Bench Top Reactor System (Parr Instrument Company) was heated to 110\u0026deg;C for at least 1 hour under vacuum and then cooled to the desired reaction temperature. A heating control system or a chiller kept the reactor temperature constant. Toluene was injected under a positive ethylene flow and the reactor was subsequently pressurized with ethylene to 200 psi and maintained for 10 minutes. The reactor was vented and repressurized to 200 psi of ethylene and maintained for another 10 minutes. The reactor was then vented, and 5.0 mL of methylene chloride solution of nickel catalyst and 5.0 mL methylene chloride solution of the organoboron cocatalyst were sequentially injected under ethylene flow. For copolymerization, the comonomer was injected after the catalyst solution. The reactor was sealed, pressurized to the desired ethylene pressure, and stirred for the desired reaction time. The reactor was then carefully vented, quenched, and poured into a solution of 400 mL methanol. The polymer was filtered and dried under vacuum to reach a constant weight. Alternatively, the reaction solution can be quenched and concentrated under vacuum before being washed with methanol to isolate the polymer before drying under vacuum.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec13\" class=\"Section2\"\u003e\n\u003ch2\u003eComputation details for counterion study\u003c/h2\u003e\n\u003cp\u003eThe computational work was carried out using the Gaussian16 suite of programs.\u003csup\u003e55\u003c/sup\u003e The geometry optimizations were performed without any symmetry constraint using the B3LYP functional, the SDD basis functions for the nickel atom, which included an ECP and an f polarization function (\u0026alpha;\u0026thinsp;=\u0026thinsp;3.130)\u003csup\u003e56\u003c/sup\u003e, and the 6-311G(d,p) basis functions for all other light atoms (Cl, F, O, N, C, B, H). The effects of dispersion forces (Grimme\u0026rsquo;s D3 empirical method)\u003csup\u003e57\u003c/sup\u003e and solvation in dichloromethane (\u0026epsilon;\u0026thinsp;=\u0026thinsp;8.93) by SMD\u003csup\u003e58\u003c/sup\u003e were included during the optimization. The ZPVE, PV, and TS corrections at 298 K were obtained with Gaussian16 from the solution of the nuclear equation using the standard ideal gas and harmonic approximations at T\u0026thinsp;=\u0026thinsp;298.15 K, which also verified the nature of all optimized geometries as local minima or first-order saddle points. A correction of 1.95 kcal mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e was applied to all G values to change the standard state from the gas phase (1 atm) to solution (1.0 M).\u003csup\u003e59\u003c/sup\u003e\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec14\" class=\"Section2\"\u003e\n\u003ch2\u003eComputation details for chainwalking study\u003c/h2\u003e\n\u003cp\u003eThe density functional theory (DFT) calculations were conducted using the Gaussian16 package.\u003csup\u003e55\u003c/sup\u003e The initial state, illustrated in Supplementary Figure S141, consisted of a polymer chain comprising 7 carbon atoms. Each structure was optimized using the generalized gradient approximation (GGA)\u003csup\u003e60,61\u003c/sup\u003e BP86\u003csup\u003e62\u0026ndash;64\u003c/sup\u003e/BSI level with spin polarization, and harmonic vibration frequencies were computed to determine the thermodynamic data. For the BSI level, the carbon (C), hydrogen (H), and nitrogen (N) atoms were evaluated using the 6-31G* basis set. The nickel (Ni) atom was treated with the quasi-relativistic LANL2DZ ECP effective core potential.\u003csup\u003e65\u003c/sup\u003e To obtain more reliable relative energies, single-point calculations were performed on the optimized structures using the BP86D3 level, which incorporates Grimme's DFTD3 correction\u003csup\u003e57,66\u003c/sup\u003e, and the BSII level, accounting for the solvation effect of toluene using the SMD\u003csup\u003e58\u003c/sup\u003e solvation model. In BSII, the 6-31G* basis set was employed for carbon (C), hydrogen (H), oxygen (O), and nitrogen (N) atoms, while the nickel (Ni) atom was treated using the Stuttgart/Dresden effective core potential (ECP) and the corresponding basis sets.\u003csup\u003e67\u003c/sup\u003e The free energies in solution, necessary for describing energy profiles, were obtained through solvation single-point calculations along with the gas-phase Gibbs free energy correction.\u003csup\u003e68,69\u003c/sup\u003e Transition states were calculated using the QST3 method implemented in Gaussian.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eDATA AVAILABLITY\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe X-ray crystallographic data for complexes \u003cstrong\u003eC1\u003c/strong\u003e, \u003cstrong\u003eC3\u003c/strong\u003e, \u003cstrong\u003eC4\u003c/strong\u003e, \u003cstrong\u003eC5\u003c/strong\u003e, \u003cstrong\u003eC7\u003c/strong\u003e, and \u003cstrong\u003eC8\u003c/strong\u003e has been deposited at the Cambridge Crystallographic Data Center (CCDC) under deposition numbers 2320308-2320313. These data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif. Supplementary Information contains detailed experimental procedures, characterization data, X-ray crystallography (Supplementary Figures S134-S139), and \u003csup\u003e1\u003c/sup\u003eH and \u003csup\u003e13\u003c/sup\u003eC NMR data for the ligands and complexes (Supplementary Figures S3-S22), as well as reaction temperature study (Supplementary Table S1), \u003csup\u003e1\u003c/sup\u003eH and \u003csup\u003e13\u003c/sup\u003eC NMR data for the polymers (Supplementary Figures S23-S63), GPC (Supplementary Figures S64-S98), DSC (Supplementary Figures S99-S133), branching trend (Supplementary Figure S1), and DFT data (Supplementary Figures S140-S145). All data can be supplied by the authors upon reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors H. S. R., Y-S. L. and E.H. thank the Robert A. Welch Foundation for funding (H-E-0041and E-2066-202110327) through the Center of Excellence in Polymer Chemistry and acknowledge the National Science Foundation (CHEM-2108576) for supporting parts of this work. R.P. thanks the CALMIP Mesocenter of the University of Toulouse for the allocation of computational resources. S.S.S. and L.C.G. were supported by NSF EFRI Award # 2029359, and acknowledge the use of the Carya, Opuntia, and Sabine Clusters and the advanced support from the Research Computing Data Core at the University of Houston.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eContributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eH.S.R. and Y-S.L. conceived the project. H.S.R. synthesized and characterized the complexes. H.S.R. and Y-S.L. performed experimental studies and polymer analysis. H.S.R., Y-S.L., and E.H. drafted the initial manuscript. H.S.R., Y-S.L., and E.H. designed and edited figures. H.S.R., Y-S.L., S.S.S., L.C.G., R.P., and E.H. edited and revised the text. E.D. and R.P. conducted DFT simulations for the counterion study and made the respective figures. S.S.S. and L.C.G. performed DFT simulations for the chain‑walking mechanism and made the respective figures. L.C.G., R.P., and E.H. supervised the study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting Interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eHustad, P. D. Frontiers in Olefin Polymerization: Reinventing the World\u0026rsquo;s Most Common Synthetic Polymers. \u003cem\u003eScience\u003c/em\u003e \u003cstrong\u003e325\u003c/strong\u003e, 704-707, doi:10.1126/science.1174927 (2009).\u003c/li\u003e\n\u003cli\u003eM\u0026uuml;lhaupt, R. Green Polymer Chemistry and Bio-based Plastics: Dreams and Reality. \u003cem\u003eMacromol. Chem. 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J.\u003cem\u003e et al.\u003c/em\u003e Gaussian 16 Rev. C.01. (2016).\u003c/li\u003e\n\u003cli\u003eEhlers, A. W.\u003cem\u003e et al.\u003c/em\u003e A set of f-polarization functions for pseudo-potential basis sets of the transition metals Sc-Cu, Y-Ag and La-Au. \u003cem\u003eChem. Phys. Lett.\u003c/em\u003e \u003cstrong\u003e208\u003c/strong\u003e, 111-114, doi:https://doi.org/10.1016/0009-2614(93)80086-5 (1993).\u003c/li\u003e\n\u003cli\u003eGrimme, S., Antony, J., Ehrlich, S. \u0026amp; Krieg, H. A consistent and accurate ab initio parametrization of density functional dispersion correction (DFT-D) for the 94 elements H-Pu. \u003cem\u003eJ. Chem. Phys.\u003c/em\u003e \u003cstrong\u003e132\u003c/strong\u003e, 154104, doi:10.1063/1.3382344 (2010).\u003c/li\u003e\n\u003cli\u003eMarenich, A. V., Cramer, C. J. \u0026amp; Truhlar, D. G. 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Acta.\u003c/em\u003e \u003cstrong\u003e77\u003c/strong\u003e, 123-141, doi:10.1007/BF01114537 (1990).\u003c/li\u003e\n\u003cli\u003eFalivene, L.\u003cem\u003e et al.\u003c/em\u003e Control of Chain Walking by Weak Neighboring Group Interactions in Unsymmetrical Catalysts. \u003cem\u003eJ. Am. Chem. Soc.\u003c/em\u003e \u003cstrong\u003e140\u003c/strong\u003e, 1305-1312, doi:10.1021/jacs.7b08975 (2018).\u003c/li\u003e\n\u003cli\u003eZhang, Y., Kang, X. \u0026amp; Jian, Z. Selective branch formation in ethylene polymerization to access precise ethylene-propylene copolymers. \u003cem\u003eNat. Commun.\u003c/em\u003e \u003cstrong\u003e13\u003c/strong\u003e, 725, doi:10.1038/s41467-022-28282-z (2022).\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003e\u003cstrong\u003eTable 1. Ethylene polymerization of C1 with different cocatalysts\u003cem\u003e\u003csup\u003ea\u003c/sup\u003e\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"605\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"7.933884297520661%\"\u003e\n \u003cp\u003eEntry\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.074380165289256%\"\u003e\n \u003cp\u003eCocatalyst\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.933884297520661%\"\u003e\n \u003cp\u003eTime\u003c/p\u003e\n \u003cp\u003e(min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.933884297520661%\"\u003e\n \u003cp\u003eYield\u003c/p\u003e\n \u003cp\u003e(g)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.727272727272727%\"\u003e\n \u003cp\u003eProductivity\u003c/p\u003e\n \u003cp\u003e(kg mol\u003csup\u003e-1\u003c/sup\u003e\u003csub\u003eNi\u003c/sub\u003e\u0026middot;h)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.074380165289256%\"\u003e\n \u003cp\u003eTOF\u003c/p\u003e\n \u003cp\u003e(10\u003csup\u003e3\u003c/sup\u003e)(h\u003csup\u003e\u0026minus;1\u003c/sup\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.074380165289256%\"\u003e\n \u003cp\u003eBranches\u003c/p\u003e\n \u003cp\u003e/1000C\u003cem\u003e\u003csup\u003eb\u003c/sup\u003e\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.074380165289256%\"\u003e\n \u003cp\u003e\u003cem\u003eM\u003c/em\u003e\u003csub\u003en\u003c/sub\u003e\u003cem\u003e\u003csup\u003ec\u003c/sup\u003e\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e(kg mol\u003csup\u003e-1\u003c/sup\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.586776859504132%\"\u003e\n \u003cp\u003e\u003cem\u003e\u0026ETH;\u003csup\u003ec\u003c/sup\u003e\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.586776859504132%\"\u003e\n \u003cp\u003e\u003cem\u003eT\u003c/em\u003e\u003csub\u003em\u003c/sub\u003e\u003cem\u003e\u003csup\u003ed\u003c/sup\u003e\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e(\u0026deg;C)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"7.933884297520661%\"\u003e\n \u003cp\u003e1\u003cem\u003e\u003csup\u003ee\u003c/sup\u003e\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.074380165289256%\"\u003e\n \u003cp\u003eMMAO\u003c/p\u003e\n \u003cp\u003e(200 eq.)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.933884297520661%\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.933884297520661%\"\u003e\n \u003cp\u003e3.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.727272727272727%\"\u003e\n \u003cp\u003e18,000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.074380165289256%\"\u003e\n \u003cp\u003e642.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.074380165289256%\"\u003e\n \u003cp\u003e27\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.074380165289256%\"\u003e\n \u003cp\u003e6.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.586776859504132%\"\u003e\n \u003cp\u003e2.47\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.586776859504132%\"\u003e\n \u003cp\u003e109.3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"7.933884297520661%\"\u003e\n \u003cp\u003e2\u003cem\u003e\u003csup\u003ee\u003c/sup\u003e\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.074380165289256%\"\u003e\n \u003cp\u003eEt\u003csub\u003e2\u003c/sub\u003eAlCl\u003c/p\u003e\n \u003cp\u003e(200 eq.)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.933884297520661%\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.933884297520661%\"\u003e\n \u003cp\u003e2.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.727272727272727%\"\u003e\n \u003cp\u003e15,000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.074380165289256%\"\u003e\n \u003cp\u003e535.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.074380165289256%\"\u003e\n \u003cp\u003e40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.074380165289256%\"\u003e\n \u003cp\u003e4.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.586776859504132%\"\u003e\n \u003cp\u003e2.11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.586776859504132%\"\u003e\n \u003cp\u003e102.7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"7.933884297520661%\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.074380165289256%\"\u003e\n \u003cp\u003eNaBArF\u003c/p\u003e\n \u003cp\u003e(1.2 eq.)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.933884297520661%\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.933884297520661%\"\u003e\n \u003cp\u003e0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.727272727272727%\"\u003e\n \u003cp\u003e360\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.074380165289256%\"\u003e\n \u003cp\u003e12.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.074380165289256%\"\u003e\n \u003cp\u003e26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.074380165289256%\"\u003e\n \u003cp\u003e8.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.586776859504132%\"\u003e\n \u003cp\u003e1.98\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.586776859504132%\"\u003e\n \u003cp\u003e108.3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"7.933884297520661%\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.074380165289256%\"\u003e\n \u003cp\u003eAgBArF\u003c/p\u003e\n \u003cp\u003e(1.2 eq.)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.933884297520661%\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.933884297520661%\"\u003e\n \u003cp\u003e3.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.727272727272727%\"\u003e\n \u003cp\u003e4,560\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.074380165289256%\"\u003e\n \u003cp\u003e162.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.074380165289256%\"\u003e\n \u003cp\u003e32\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.074380165289256%\"\u003e\n \u003cp\u003e6.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.586776859504132%\"\u003e\n \u003cp\u003e2.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.586776859504132%\"\u003e\n \u003cp\u003e105.2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"7.933884297520661%\"\u003e\n \u003cp\u003e5\u003cem\u003e\u003csup\u003ef\u003c/sup\u003e\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.074380165289256%\"\u003e\n \u003cp\u003eAgBArF\u003c/p\u003e\n \u003cp\u003e(1.2 eq.)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.933884297520661%\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.933884297520661%\"\u003e\n \u003cp\u003e3.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.727272727272727%\"\u003e\n \u003cp\u003e7,680\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.074380165289256%\"\u003e\n \u003cp\u003e274.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.074380165289256%\"\u003e\n \u003cp\u003e41\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.074380165289256%\"\u003e\n \u003cp\u003e4.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.586776859504132%\"\u003e\n \u003cp\u003e2.17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.586776859504132%\"\u003e\n \u003cp\u003e104.6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"7.933884297520661%\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.074380165289256%\"\u003e\n \u003cp\u003eB(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e\u003c/p\u003e\n \u003cp\u003e(10 eq.)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.933884297520661%\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.933884297520661%\"\u003e\n \u003cp\u003e2.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.727272727272727%\"\u003e\n \u003cp\u003e2,880\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.074380165289256%\"\u003e\n \u003cp\u003e102.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.074380165289256%\"\u003e\n \u003cp\u003e25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.074380165289256%\"\u003e\n \u003cp\u003e11.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.586776859504132%\"\u003e\n \u003cp\u003e1.93\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.586776859504132%\"\u003e\n \u003cp\u003e108.6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eConditions: \u003cem\u003e\u003csup\u003ea\u003c/sup\u003e\u003c/em\u003e5 \u0026mu;mol of \u003cstrong\u003eC1\u003c/strong\u003e,\u003csup\u003e\u0026nbsp;\u003c/sup\u003e400 psi ethylene, 45 mL of toluene, 20 \u0026deg;C. \u003cem\u003e\u003csup\u003eb\u003c/sup\u003e\u003c/em\u003eDetermined by \u003csup\u003e1\u003c/sup\u003eH NMR in D\u003csub\u003e2\u003c/sub\u003e‑tetrachloroethane at 125 \u0026deg;C. \u003cem\u003e\u003csup\u003ec\u003c/sup\u003e\u003c/em\u003eDetermined by GPC in 1,2,4-trichlorobenzene at 160 \u0026deg;C using polystyrene calibration. \u003cem\u003e\u003csup\u003ed\u003c/sup\u003e\u003c/em\u003eDetermined by differential scanning calorimetry. \u003cem\u003e\u003csup\u003ee\u003c/sup\u003e\u003c/em\u003e2 \u0026mu;mol of \u003cstrong\u003eC1\u003c/strong\u003e. \u003cem\u003e\u003csup\u003ef\u003c/sup\u003e\u003c/em\u003eIncluded 10 equivalents of B(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3.\u003c/sub\u003e TOF = Turn-Over Frequency, \u003cem\u003eM\u003c/em\u003e\u003csub\u003en\u003c/sub\u003e = Number-Average Molecular Weight, \u003cem\u003e\u0026ETH;\u003c/em\u003e = Dispersity, \u003cem\u003eT\u003c/em\u003e\u003csub\u003em\u003c/sub\u003e = Melting Temperature.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable\u0026nbsp;2.\u003c/strong\u003e \u003cstrong\u003eEthylene polymerization of C1‑C8 at 20\u0026nbsp;\u0026deg;C\u003cem\u003e\u003csup\u003ea\u003c/sup\u003e\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"624\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003eEntry\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003eCatalyst\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003eTime\u003c/p\u003e\n \u003cp\u003e(min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003eYield\u003c/p\u003e\n \u003cp\u003e(g)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.300319488817891%\"\u003e\n \u003cp\u003eProductivity\u003c/p\u003e\n \u003cp\u003e(kg mol\u003csup\u003e-1\u003c/sup\u003e\u003csub\u003eNi\u003c/sub\u003e\u0026middot;h)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.702875399361023%\"\u003e\n \u003cp\u003eTOF\u003c/p\u003e\n \u003cp\u003e(10\u003csup\u003e3\u003c/sup\u003e)(h\u003csup\u003e\u0026minus;1\u003c/sup\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.702875399361023%\"\u003e\n \u003cp\u003eBranches\u003c/p\u003e\n \u003cp\u003e/1000C\u003cem\u003e\u003csup\u003eb\u003c/sup\u003e\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.702875399361023%\"\u003e\n \u003cp\u003e\u003cem\u003eM\u003c/em\u003e\u003csub\u003en\u003c/sub\u003e\u003cem\u003e\u003csup\u003ec\u003c/sup\u003e\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e(kg mol\u003csup\u003e-1\u003c/sup\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e\u003cem\u003e\u0026ETH;\u003csup\u003ec\u003c/sup\u003e\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e\u003cem\u003eT\u003c/em\u003e\u003csub\u003em\u003c/sub\u003e\u003cem\u003e\u003csup\u003ed\u003c/sup\u003e\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e(\u0026deg;C)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e1\u003cem\u003e\u003csup\u003ee\u003c/sup\u003e\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003eC1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e2.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.300319488817891%\"\u003e\n \u003cp\u003e2,880\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.702875399361023%\"\u003e\n \u003cp\u003e102.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.702875399361023%\"\u003e\n \u003cp\u003e25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.702875399361023%\"\u003e\n \u003cp\u003e11.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e1.93\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e108.6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003eC3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e1.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.300319488817891%\"\u003e\n \u003cp\u003e1,020\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.702875399361023%\"\u003e\n \u003cp\u003e36.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.702875399361023%\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.702875399361023%\"\u003e\n \u003cp\u003e7.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e1.94\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e101.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003eC5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e1.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.300319488817891%\"\u003e\n \u003cp\u003e960\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.702875399361023%\"\u003e\n \u003cp\u003e34.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.702875399361023%\"\u003e\n \u003cp\u003e37\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.702875399361023%\"\u003e\n \u003cp\u003e11.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e1.97\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e99.7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003eC7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e0.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.300319488817891%\"\u003e\n \u003cp\u003e480\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.702875399361023%\"\u003e\n \u003cp\u003e16.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.702875399361023%\"\u003e\n \u003cp\u003e26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.702875399361023%\"\u003e\n \u003cp\u003e153.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e1.77\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e101.5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e5\u003cem\u003e\u003csup\u003ee\u003c/sup\u003e\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003eC2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e1.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.300319488817891%\"\u003e\n \u003cp\u003e300\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.702875399361023%\"\u003e\n \u003cp\u003e10.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.702875399361023%\"\u003e\n \u003cp\u003e36\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.702875399361023%\"\u003e\n \u003cp\u003e6.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e1.92\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e102.1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003eC4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e0.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.300319488817891%\"\u003e\n \u003cp\u003e90\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.702875399361023%\"\u003e\n \u003cp\u003e3.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.702875399361023%\"\u003e\n \u003cp\u003e49\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.702875399361023%\"\u003e\n \u003cp\u003e23.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e1.75\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e112.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003eC6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e1.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.300319488817891%\"\u003e\n \u003cp\u003e120\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.702875399361023%\"\u003e\n \u003cp\u003e4.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.702875399361023%\"\u003e\n \u003cp\u003e45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.702875399361023%\"\u003e\n \u003cp\u003e37.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e1.62\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e82.9\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003eC8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e180\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.300319488817891%\"\u003e\n \u003cp\u003e167\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.702875399361023%\"\u003e\n \u003cp\u003e0.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.702875399361023%\"\u003e\n \u003cp\u003e42\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.702875399361023%\"\u003e\n \u003cp\u003e71.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e2.06\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.26517571884984%\"\u003e\n \u003cp\u003e91.5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eConditions: \u003cem\u003e\u003csup\u003ea\u003c/sup\u003e\u003c/em\u003e10\u0026nbsp;\u0026mu;mol of Ni catalyst,\u003csup\u003e\u0026nbsp;\u003c/sup\u003e10 equivalent of B(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e, 400 psi ethylene, 45 mL of toluene. \u003cem\u003e\u003csup\u003eb\u003c/sup\u003e\u003c/em\u003eDetermined by \u003csup\u003e1\u003c/sup\u003eH NMR in D\u003csub\u003e2\u003c/sub\u003e‑tetrachloroethane at 125 \u0026deg;C. \u003cem\u003e\u003csup\u003ec\u003c/sup\u003e\u003c/em\u003eDetermined by GPC in 1,2,4-trichlorobenzene at 160 \u0026deg;C using polystyrene calibration. \u003cem\u003e\u003csup\u003ed\u003c/sup\u003e\u003c/em\u003eDetermined by differential scanning calorimetry. \u003cem\u003e\u003csup\u003ee\u003c/sup\u003e\u003c/em\u003e5 \u0026mu;mol of Ni. TOF = Turn-Over Frequency, \u003cem\u003eM\u003c/em\u003e\u003csub\u003en\u003c/sub\u003e = Number-Average Molecular Weight, \u003cem\u003e\u0026ETH;\u003c/em\u003e = Dispersity, \u003cem\u003eT\u003c/em\u003e\u003csub\u003em\u003c/sub\u003e = Melting Temperature.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 3.\u003c/strong\u003e \u003cstrong\u003eEthylene polymerization of C1 at 0-80 \u0026deg;C\u003cem\u003e\u003csup\u003ea\u003c/sup\u003e\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"622\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"5.152979066022544%\" rowspan=\"2\"\u003e\n \u003cp\u003eEntry\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"5.958132045088567%\" rowspan=\"2\"\u003e\n \u003cp\u003eTemp\u003c/p\u003e\n \u003cp\u003e(\u0026deg;C)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"5.797101449275362%\" rowspan=\"2\"\u003e\n \u003cp\u003eTime\u003c/p\u003e\n \u003cp\u003e(min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"5.475040257648954%\" rowspan=\"2\"\u003e\n \u003cp\u003eYield\u003c/p\u003e\n \u003cp\u003e(g)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.560386473429952%\" rowspan=\"2\"\u003e\n \u003cp\u003eProductivity\u003c/p\u003e\n \u003cp\u003e(kg mol\u003csup\u003e‑1\u003c/sup\u003e\u003csub\u003eNi\u003c/sub\u003e\u0026middot;h)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.017713365539452%\" rowspan=\"2\"\u003e\n \u003cp\u003eTOF\u003c/p\u003e\n \u003cp\u003e(10\u003csup\u003e3\u003c/sup\u003e)(h\u003csup\u003e\u0026minus;1\u003c/sup\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.339774557165862%\" rowspan=\"2\"\u003e\n \u003cp\u003e\u003cem\u003eM\u003c/em\u003e\u003csub\u003en\u003c/sub\u003e\u003cem\u003e\u003csup\u003eb\u003c/sup\u003e\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e(kg mol\u003csup\u003e-1\u003c/sup\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"4.669887278582931%\" rowspan=\"2\"\u003e\n \u003cp\u003e\u003cem\u003e\u0026ETH;\u003csup\u003eb\u003c/sup\u003e\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"5.797101449275362%\" rowspan=\"2\"\u003e\n \u003cp\u003e\u003cem\u003eT\u003c/em\u003e\u003csub\u003em\u003c/sub\u003e\u003cem\u003e\u003csup\u003ec\u003c/sup\u003e\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e(\u0026deg;C)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.856682769726248%\" rowspan=\"2\"\u003e\n \u003cp\u003eBranches\u003c/p\u003e\n \u003cp\u003e/1000C\u003cem\u003e\u003csup\u003ed\u003c/sup\u003e\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.214170692431562%\" colspan=\"6\"\u003e\n \u003cp\u003eBranching Distribution (%)\u003cem\u003e\u003csup\u003ee\u003c/sup\u003e\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"0.1610305958132045%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"17.058823529411764%\"\u003e\n \u003cp\u003eMe\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.058823529411764%\"\u003e\n \u003cp\u003eEt\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.647058823529413%\"\u003e\n \u003cp\u003ePr\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.117647058823529%\"\u003e\n \u003cp\u003eBu\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.647058823529413%\"\u003e\n \u003cp\u003eAm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.470588235294116%\" colspan=\"2\"\u003e\n \u003cp\u003eLg\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"5.152979066022544%\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"5.958132045088567%\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"5.797101449275362%\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"5.475040257648954%\"\u003e\n \u003cp\u003e1.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.560386473429952%\"\u003e\n \u003cp\u003e440\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.017713365539452%\"\u003e\n \u003cp\u003e15.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.339774557165862%\"\u003e\n \u003cp\u003e65.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"4.669887278582931%\"\u003e\n \u003cp\u003e1.65\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"5.797101449275362%\"\u003e\n \u003cp\u003e127.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.856682769726248%\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"4.669887278582931%\"\u003e\n \u003cp\u003e100\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"4.669887278582931%\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"4.830917874396135%\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"3.864734299516908%\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"4.830917874396135%\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"4.508856682769726%\" colspan=\"2\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"5.152979066022544%\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"5.958132045088567%\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"5.797101449275362%\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"5.475040257648954%\"\u003e\n \u003cp\u003e2.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.560386473429952%\"\u003e\n \u003cp\u003e2,880\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.017713365539452%\"\u003e\n \u003cp\u003e102.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.339774557165862%\"\u003e\n \u003cp\u003e11.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"4.669887278582931%\"\u003e\n \u003cp\u003e1.93\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"5.797101449275362%\"\u003e\n \u003cp\u003e108.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.856682769726248%\"\u003e\n \u003cp\u003e25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"4.669887278582931%\"\u003e\n \u003cp\u003e78.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"4.669887278582931%\"\u003e\n \u003cp\u003e3.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"4.830917874396135%\"\u003e\n \u003cp\u003e1.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"3.864734299516908%\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"4.830917874396135%\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"4.508856682769726%\" colspan=\"2\"\u003e\n \u003cp\u003e16.1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"5.152979066022544%\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"5.958132045088567%\"\u003e\n \u003cp\u003e40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"5.797101449275362%\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"5.475040257648954%\"\u003e\n \u003cp\u003e1.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.560386473429952%\"\u003e\n \u003cp\u003e2,160\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.017713365539452%\"\u003e\n \u003cp\u003e77.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.339774557165862%\"\u003e\n \u003cp\u003e3.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"4.669887278582931%\"\u003e\n \u003cp\u003e1.67\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"5.797101449275362%\"\u003e\n \u003cp\u003e64.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.856682769726248%\"\u003e\n \u003cp\u003e56\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"4.669887278582931%\"\u003e\n \u003cp\u003e68.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"4.669887278582931%\"\u003e\n \u003cp\u003e3.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"4.830917874396135%\"\u003e\n \u003cp\u003e2.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"3.864734299516908%\"\u003e\n \u003cp\u003e2.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"4.830917874396135%\"\u003e\n \u003cp\u003e3.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"4.508856682769726%\" colspan=\"2\"\u003e\n \u003cp\u003e20.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"5.152979066022544%\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"5.958132045088567%\"\u003e\n \u003cp\u003e60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"5.797101449275362%\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"5.475040257648954%\"\u003e\n \u003cp\u003e2.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.560386473429952%\"\u003e\n \u003cp\u003e2,640\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.017713365539452%\"\u003e\n \u003cp\u003e94.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.339774557165862%\"\u003e\n \u003cp\u003e2.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"4.669887278582931%\"\u003e\n \u003cp\u003e1.51\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"5.797101449275362%\"\u003e\n \u003cp\u003e9.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.856682769726248%\"\u003e\n \u003cp\u003e95\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"4.669887278582931%\"\u003e\n \u003cp\u003e65.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"4.669887278582931%\"\u003e\n \u003cp\u003e4.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"4.830917874396135%\"\u003e\n \u003cp\u003e2.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"3.864734299516908%\"\u003e\n \u003cp\u003e2.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"4.830917874396135%\"\u003e\n \u003cp\u003e4.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"4.508856682769726%\" colspan=\"2\"\u003e\n \u003cp\u003e20.7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"5.152979066022544%\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"5.958132045088567%\"\u003e\n \u003cp\u003e80\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"5.797101449275362%\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"5.475040257648954%\"\u003e\n \u003cp\u003e0.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.560386473429952%\"\u003e\n \u003cp\u003e840\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.017713365539452%\"\u003e\n \u003cp\u003e30.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.339774557165862%\"\u003e\n \u003cp\u003e1.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"4.669887278582931%\"\u003e\n \u003cp\u003e1.74\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"5.797101449275362%\"\u003e\n \u003cp\u003e-23.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.856682769726248%\"\u003e\n \u003cp\u003e127\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"4.669887278582931%\"\u003e\n \u003cp\u003e57.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"4.669887278582931%\"\u003e\n \u003cp\u003e4.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"4.830917874396135%\"\u003e\n \u003cp\u003e2.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"3.864734299516908%\"\u003e\n \u003cp\u003e2.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"4.830917874396135%\"\u003e\n \u003cp\u003e6.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"4.508856682769726%\" colspan=\"2\"\u003e\n \u003cp\u003e27.5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eConditions: \u003cem\u003e\u003csup\u003ea\u003c/sup\u003e\u003c/em\u003e5\u0026nbsp;\u0026mu;mol of Ni catalyst,\u003csup\u003e\u0026nbsp;\u003c/sup\u003e10 equivalent of B(C\u003csub\u003e6\u003c/sub\u003eF\u003csub\u003e5\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e, 400 psi ethylene, 45 mL of toluene. \u003cem\u003e\u003csup\u003eb\u003c/sup\u003e\u003c/em\u003eDetermined by GPC in 1,2,4-trichlorobenzene at 160 \u0026deg;C using polystyrene calibration. \u003cem\u003e\u003csup\u003ec\u003c/sup\u003e\u003c/em\u003eDetermined by differential scanning calorimetry.\u003cem\u003e\u003csup\u003e\u0026nbsp;d\u003c/sup\u003e\u003c/em\u003eDetermined by \u003csup\u003e1\u003c/sup\u003eH NMR in D\u003csub\u003e2\u003c/sub\u003e‑tetrachloroethane at 125 \u0026deg;C. \u003cem\u003e\u003csup\u003ee\u003c/sup\u003e\u003c/em\u003eDetermined by \u003csup\u003e13\u003c/sup\u003eC NMR in D\u003csub\u003e2\u003c/sub\u003e‑tetrachloroethane at 125 \u0026deg;C. TOF = Turn-Over Frequency, \u003cem\u003eM\u003c/em\u003e\u003csub\u003en\u003c/sub\u003e = Number-Average Molecular Weight, \u003cem\u003e\u0026ETH;\u003c/em\u003e = Dispersity, \u003cem\u003eT\u003c/em\u003e\u003csub\u003em\u003c/sub\u003e = Melting Temperature, Me = Methyl, Et = Ethyl, Pr = Propyl, Bu = Butyl, Am = Amyl, Lg = Large.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 4. Ethylene/polar monomer Copolymerization of\u003c/strong\u003e \u003cstrong\u003eC7\u003cem\u003e\u003csup\u003ea\u003c/sup\u003e\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"606\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"7.578253706754531%\"\u003e\n \u003cp\u003eEntry\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.873146622734762%\"\u003e\n \u003cp\u003eMonomer\u003c/p\u003e\n \u003cp\u003e[M]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.578253706754531%\"\u003e\n \u003cp\u003eTemp.\u003c/p\u003e\n \u003cp\u003e(\u0026deg;C)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.578253706754531%\"\u003e\n \u003cp\u003eYield\u003c/p\u003e\n \u003cp\u003e(g)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.214168039538714%\"\u003e\n \u003cp\u003eTOF\u003c/p\u003e\n \u003cp\u003e(10\u003csup\u003e3\u003c/sup\u003e)(h\u003csup\u003e\u0026minus;1\u003c/sup\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.70840197693575%\"\u003e\n \u003cp\u003eBranches\u003c/p\u003e\n \u003cp\u003e/1000C\u003cem\u003e\u003csup\u003eb\u003c/sup\u003e\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.70840197693575%\"\u003e\n \u003cp\u003e\u003cem\u003eM\u003c/em\u003e\u003csub\u003en\u003c/sub\u003e\u003cem\u003e\u003csup\u003ec\u003c/sup\u003e\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e(kg mol\u003csup\u003e-1\u003c/sup\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.731466227347612%\"\u003e\n \u003cp\u003e\u003cem\u003e\u0026ETH;\u003csup\u003ec\u003c/sup\u003e\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.731466227347612%\"\u003e\n \u003cp\u003eIncorp.\u003c/p\u003e\n \u003cp\u003e(mol %)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.896210873146623%\"\u003e\n \u003cp\u003e\u003cem\u003eT\u003c/em\u003e\u003csub\u003em\u003c/sub\u003e\u003cem\u003e\u003csup\u003ed\u003c/sup\u003e\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e(\u0026deg;C)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.401976935749587%\"\u003e\n \u003cp\u003e\u003cem\u003eT\u003c/em\u003e\u003csub\u003eg\u003c/sub\u003e\u003cem\u003e\u003csup\u003ed\u003c/sup\u003e\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e(\u0026deg;C)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"7.578253706754531%\"\u003e\n \u003cp\u003e1\u003cem\u003e\u003csup\u003ee\u003c/sup\u003e\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.873146622734762%\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.578253706754531%\"\u003e\n \u003cp\u003e40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.578253706754531%\"\u003e\n \u003cp\u003e3.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.214168039538714%\"\u003e\n \u003cp\u003e11.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.70840197693575%\"\u003e\n \u003cp\u003e57\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.70840197693575%\"\u003e\n \u003cp\u003e111.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.731466227347612%\"\u003e\n \u003cp\u003e1.71\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.731466227347612%\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.896210873146623%\"\u003e\n \u003cp\u003e68.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.401976935749587%\"\u003e\n \u003cp\u003e-36.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"7.578253706754531%\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.873146622734762%\"\u003e\n \u003cp\u003eVTEoS\u003c/p\u003e\n \u003cp\u003e[0.5]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.578253706754531%\"\u003e\n \u003cp\u003e40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.578253706754531%\"\u003e\n \u003cp\u003e0.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.214168039538714%\"\u003e\n \u003cp\u003e0.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.70840197693575%\"\u003e\n \u003cp\u003e52\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.70840197693575%\"\u003e\n \u003cp\u003e66.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.731466227347612%\"\u003e\n \u003cp\u003e1.60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.731466227347612%\"\u003e\n \u003cp\u003e3.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.896210873146623%\"\u003e\n \u003cp\u003e56.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.401976935749587%\"\u003e\n \u003cp\u003e-55.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"7.578253706754531%\"\u003e\n \u003cp\u003e3\u003cem\u003e\u003csup\u003ef\u003c/sup\u003e\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.873146622734762%\"\u003e\n \u003cp\u003eVTEoS\u003c/p\u003e\n \u003cp\u003e[0.5]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.578253706754531%\"\u003e\n \u003cp\u003e60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.578253706754531%\"\u003e\n \u003cp\u003e1.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.214168039538714%\"\u003e\n \u003cp\u003e2.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.70840197693575%\"\u003e\n \u003cp\u003e69\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.70840197693575%\"\u003e\n \u003cp\u003e33.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.731466227347612%\"\u003e\n \u003cp\u003e1.68\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.731466227347612%\"\u003e\n \u003cp\u003e4.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.896210873146623%\"\u003e\n \u003cp\u003e27.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.401976935749587%\"\u003e\n \u003cp\u003e-64.7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"7.578253706754531%\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.873146622734762%\"\u003e\n \u003cp\u003eVTEoS\u003c/p\u003e\n \u003cp\u003e[1.0]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.578253706754531%\"\u003e\n \u003cp\u003e40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.578253706754531%\"\u003e\n \u003cp\u003e0.45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.214168039538714%\"\u003e\n \u003cp\u003e0.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.70840197693575%\"\u003e\n \u003cp\u003e50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.70840197693575%\"\u003e\n \u003cp\u003e48.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.731466227347612%\"\u003e\n \u003cp\u003e1.79\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.731466227347612%\"\u003e\n \u003cp\u003e5.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.896210873146623%\"\u003e\n \u003cp\u003e46.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.401976935749587%\"\u003e\n \u003cp\u003e-63.6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"7.578253706754531%\"\u003e\n \u003cp\u003e5\u003cem\u003e\u003csup\u003eg\u003c/sup\u003e\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.873146622734762%\"\u003e\n \u003cp\u003eMA\u003c/p\u003e\n \u003cp\u003e[0.1]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.578253706754531%\"\u003e\n \u003cp\u003e40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.578253706754531%\"\u003e\n \u003cp\u003e0.15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.214168039538714%\"\u003e\n \u003cp\u003e0.06\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.70840197693575%\"\u003e\n \u003cp\u003e61\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.70840197693575%\"\u003e\n \u003cp\u003e55.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.731466227347612%\"\u003e\n \u003cp\u003e1.57\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.731466227347612%\"\u003e\n \u003cp\u003e0.34\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.896210873146623%\"\u003e\n \u003cp\u003e73.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.401976935749587%\"\u003e\n \u003cp\u003e-39.2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"7.578253706754531%\"\u003e\n \u003cp\u003e6\u003cem\u003e\u003csup\u003eg\u003c/sup\u003e\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.873146622734762%\"\u003e\n \u003cp\u003eMA\u003c/p\u003e\n \u003cp\u003e[0.1]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.578253706754531%\"\u003e\n \u003cp\u003e60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.578253706754531%\"\u003e\n \u003cp\u003e0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.214168039538714%\"\u003e\n \u003cp\u003e0.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.70840197693575%\"\u003e\n \u003cp\u003e83\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.70840197693575%\"\u003e\n \u003cp\u003e35.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.731466227347612%\"\u003e\n \u003cp\u003e1.66\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.731466227347612%\"\u003e\n \u003cp\u003e2.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.896210873146623%\"\u003e\n \u003cp\u003e26.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.401976935749587%\"\u003e\n \u003cp\u003e-51.9\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"7.578253706754531%\"\u003e\n \u003cp\u003e7\u003cem\u003e\u003csup\u003eg\u003c/sup\u003e\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.873146622734762%\"\u003e\n \u003cp\u003eVAc\u003c/p\u003e\n \u003cp\u003e[0.25]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.578253706754531%\"\u003e\n \u003cp\u003e60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.578253706754531%\"\u003e\n \u003cp\u003e0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.214168039538714%\"\u003e\n \u003cp\u003e0.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.70840197693575%\"\u003e\n \u003cp\u003e78\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.70840197693575%\"\u003e\n \u003cp\u003e53.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.731466227347612%\"\u003e\n \u003cp\u003e1.65\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.731466227347612%\"\u003e\n \u003cp\u003e0.26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.896210873146623%\"\u003e\n \u003cp\u003e46.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.401976935749587%\"\u003e\n \u003cp\u003e-49.8\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eConditions: \u003cem\u003e\u003csup\u003ea\u003c/sup\u003e\u003c/em\u003e20 \u0026mu;mol of \u003cstrong\u003eC7\u003c/strong\u003e, 1.2 equivalents of AgBArF, 400 psi ethylene, 45 mL of toluene, 120 min. \u003cem\u003e\u003csup\u003eb\u003c/sup\u003e\u003c/em\u003eDetermined by \u003csup\u003e1\u003c/sup\u003eH NMR in D\u003csub\u003e2\u003c/sub\u003e‑tetrachloroethane at 125 \u0026deg;C. \u003cem\u003e\u003csup\u003ec\u003c/sup\u003e\u003c/em\u003eDetermined by GPC in 1,2,4-trichlorobenzene at 160 \u0026deg;C using polystyrene calibration. \u003cem\u003e\u003csup\u003ed\u003c/sup\u003e\u003c/em\u003eDetermined by differential scanning calorimetry. \u003cem\u003e\u003csup\u003ee\u003c/sup\u003e\u003c/em\u003e10 \u0026mu;mol of \u003cstrong\u003eC7\u003c/strong\u003e, 60 min. \u003cem\u003e\u003csup\u003ef\u003c/sup\u003e\u003c/em\u003e10 umol of \u003cstrong\u003eC7\u003c/strong\u003e, \u003cem\u003e\u003csup\u003eg\u003c/sup\u003e\u003c/em\u003e240 min. [M] = molar concentration, TOF = Turn-Over Frequency, \u003cem\u003eM\u003c/em\u003e\u003csub\u003en\u003c/sub\u003e = Number-Average Molecular Weight, \u003cem\u003e\u0026ETH;\u003c/em\u003e = Dispersity, \u003cem\u003eT\u003c/em\u003e\u003csub\u003em\u003c/sub\u003e = Melting Temperature, VTEoS = vinyltriethoxysilane, MA = methyl acrylate, VAc = vinyl acetate.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-3773688/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-3773688/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eWhile current research on Ni-catalyzed olefin polymerization predominantly focuses on ligand design, ion-pair interactions remain largely unexplored. We report the development of air-stable carbyl iminopyridyl Ni\u003csup\u003eII\u003c/sup\u003e precatalysts to enable an investigation of inner- and outersphere Ni ion-pairs. The use of innersphere organoboron counterions allows the Ni complexes to access higher molecular weight homo/co-polymers and regulate the density and distribution of polyethylene branches. Moreover, implementing a phenyl group on the tether carbon functioned as a rotational barrier, producing higher molecular weight polymers compared to methylsubstituted analogs. A controlled incorporation of shortchain branches was achieved under high ethylene pressure, circumventing the need for elaborate ligand design, low monomer pressures, and the copolymerization with α-olefins. DFT calculations further elucidated the ion-pair interactions and controlled chain-walking mechanism. Here, we provide a new perspective to manipulate the iminopyridyl Ni\u003csup\u003eII\u003c/sup\u003e system leveraging both ion-pair interactions and ligand design to govern polyolefin molecular weights and microstructures.\u003c/p\u003e","manuscriptTitle":"Unraveling Organoboron/Nickel Ion-Pair Interactions via Benchtop-Stable Carbyl Iminopyridyl NiII Complexes for Olefin Polymerization","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-01-03 10:25:02","doi":"10.21203/rs.3.rs-3773688/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"3e216d0c-17e6-44c5-83bf-84884378c512","owner":[],"postedDate":"January 3rd, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":27921517,"name":"Physical sciences/Chemistry/Catalysis/Homogeneous catalysis"},{"id":27921518,"name":"Physical sciences/Chemistry/Polymer chemistry/Polymer synthesis"}],"tags":[],"updatedAt":"2024-04-20T19:45:17+00:00","versionOfRecord":[],"versionCreatedAt":"2024-01-03 10:25:02","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-3773688","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-3773688","identity":"rs-3773688","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}