Synthesis, Structure, and Properties of a Polymer Complex of Copper(II) With Maleic Acid

Synthesis, Structure, and Properties of a Polymer Complex of Copper(II) With Maleic Acid | 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 Research Article Synthesis, Structure, and Properties of a Polymer Complex of Copper(II) With Maleic Acid Esmira Arif Aga Guliyeva, Ajdar Akper Mejidov, Rayyat Huseyn Ismayilov, and 5 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7140677/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 04 Dec, 2025 Read the published version in Transition Metal Chemistry → Version 1 posted 4 You are reading this latest preprint version Abstract A new polymeric copper(II) complex with maleic acid, used as a dicarboxylate ligand, were synthesized Na₂[Cu(C₄H₂O₄)₂]·xH₂O. The resulting complex was characterized by elemental analysis, infrared and UV–visible spectroscopy, and X-ray crystallography. Spectroscopic data indicate that the maleinate ion coordinates in a chelating bidentate mode, creating a distorted octahedral coordination environment around Cu(II). X-ray crystallography confirmed the formulation Na₂[Cu(C₄H₂O₄)₂]·xH₂O and revealed that the central Cu²⁺ ion is in a distorted octahedral geometry. The maleinate ion acts as a bidentate chelator, coordinating through two carboxylate oxygens to form a stable five-membered ring. Two water molecules complete the coordination sphere of the Cu center, yielding a [Cu(C₄H₂O₄)(H₂O)₂]⁻ unit This study extends our understanding of the coordination behavior of π-conjugated dicarboxylic acids with transition-metal ions. Molecular docking studies demonstrated that the polymeric copper(II)–maleic acid complex exhibited strong binding affinity toward B-DNA (1BNA), with a binding energy of − 10.2 kcal/mol and multiple stable hydrogen bond interactions. copper(II) complex maleic acid copper acetate coordination chemistry IR spectroscopy X-ray crystallography Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 1. Introduction Coordination compounds of copper(II) are of significant interest due to their structural diversity, catalytic activity, photochemical properties, and biological relevance [ 1 – 3 ]. Cu(II) complexes play important roles in fields such as the development of functional materials, catalyst synthesis, and the creation of antibacterial and anticancer agents. Special attention is given to complexes featuring organic acids with multiple coordination sites, particularly dicarboxylic acids. Maleic acid (cisbutenedioic acid) is a promising dicarboxylate ligand containing two closely spaced carboxyl groups capable of forming stable chelate complexes with transition metals. Due to its cis configuration, maleic acid exhibits distinct coordination behavior compared to its trans isomer, fumaric acid [ 4 , 5 ]. These structural characteristics make maleic acid particularly interesting for the design of novel coordination polymers. The biological activity of the copper(II)-maleinate complex arises from both the known antibacterial and antifungal properties of Cu²⁺ ions and the potential metabolic activity of the maleinate anion, a derivative of maleic acid. Copper(II) acts as an essential cofactor in numerous biological processes, including redox catalysis, electron transport, and the detoxification of reactive oxygen species. Cu(II) complexes are capable of interacting with bacterial proteins, enzymes, and nucleic acids, thereby disrupting their biological functions. Coordination with maleinate helps stabilize the copper ion in a biologically active form and may enhance its permeability across cell membranes[6–7]. Although extensive studies have been conducted on Cu complexes with other dicarboxylates such as fumarate, tartrate, and oxalate [ 8 – 10 ], copper maleinate complexes remain underexplored. Available data are fragmentary and mainly concern monomeric complexes or poorly defined coordination environments [ 11 , 12 ]. In our previous work [ 13 ], we obtained a polymeric, polynuclear heterometallic maleinate complex of Mn(II) and Co(II), [Co х Mn 1-x (OOCCH = CHCOO).(H 2 O) 2 ] n by reacting mononuclear bismaleinate tetratedrate cobalt with manganese acetate. The present study aims to synthesize a novel polynuclear Cu(II) maleinate complex under alkaline conditions and to comprehensively characterize its structure Na₂[Cu(C₄H₂O₄)₂]·xH₂O. Particular focus is placed on elucidating the coordination environment of the Cu ion and the spatial organization of the polymeric matrix. Characterization methods include IR and UV–visible spectroscopy, elemental analysis, thermogravimetric analysis, and X-ray single crystal diffraction, providing an integrated picture of the complex’s structure. The results expand our understanding of πconjugated dicarboxylate coordination possibilities and their potential in the development of new transition-metal–based materials. 2. Experimental 2.1. General and spectroscopic measurements All chemicals were used as received without further purification. Copper(II) chloride, maleic acid (C 4 H 4 O 4 ), and sodium hydroxide (NaOH) were of analytical grade (SigmaAldrich). FT-IR spectra of samples in vaseline oil were recorded in the range 4000–400 cm⁻¹ using a Nicolet IS10 spectrophotometer. Electronic absorption spectra were obtained with a SPECORD 50 spectrophotometer in aqueous solution over the UV range (200–400 nm) and visible region (400–1100 nm). Thermogravimetric analysis (TGA) was performed using a NETZSCH STA 449 F3 derivateograph under an inert atmosphere. Elemental analysis was carried out at the Tubitak Analytical Laboratory (Ankara) using a LECO CHNS 932 analyzer. 2.2. Synthesis of Na₂[Cu(C₄H₂O₄)₂]·xH₂O Copper(II) chloride (0.199 g, 1 mmol) was dissolved in 20 mL of water. To this solution, maleic acid (0.232 g, 2 mmol) was added and stirred at ambient temperature. The pH was adjusted to 6.0 using a NaOH solution. The resulting mixture was left undisturbed for 4–5 days, during which blue crystals (melting point > 250°C) formed. The crystals were filtered and dried in vacuo at room temperature, yielding 0.75 g (80%).For C₈H₈CuNa₂O₁₀: calculated: C 25.66%, H 2.13%, Cu 17.11%, Na 12.30%; found: C 25.70%, H 2.10%, Cu 17.18%, Na 12.25%.IR (ν, cm⁻¹): ν as (COO⁻) 1500, 1590; ν s (COO⁻) 1400, 1420. 2.3. Crystal Structure Determination Single-crystal X-ray diffraction was performed on a Bruker APEX-3 CCD diffractometer using monochromatized Mo Kα radiation (λ = 0.71073 Å) at 293 K [ 14 ]. The empirical formula is C₈H₈CuNa₂O₁₀; (FW = 373.63). Unit cell parameters: a = 9.119(2) Å, b = 3.6871(8) Å, c = 17.913(4) Å, β = 92.557(8)°, V = 601.7(2) ų. Structure solution was done using SHELXS [ 15 ], and refinement using SHELXL [ 16 ] via least-squares on F². The refinement converged with R = 0.037, wR = 0.073, S = 1.11 for 1241 reflections with I > 2σ(I). The maximum and minimum residual electron densities are + 0.38 and − 0.39 e·Å⁻³, indicating a high-quality model. CIF preparation and structural visualization were completed with WinGX and Mercury. All hydrogen atoms were placed using constraints. The complex exhibits good crystallographic symmetry and stability, making it suitable for diverse chemical investigations. Crystallographic data and refinement details for Na₂[Cu(C₄H₂O₄)₂]·xH₂O are summarized in Table 1 . Table 1 Crystallographic data and refinement details for Na₂[Cu(C₄H₂O₄)₂]·xH₂O Empirical formula C₈H₈CuNa₂O₁₀ Formula weight 373.66 Temperature/K 293 Crystal system monoclinic Space group P2 1 / n a/Å 9.119 (2) b/Å 3.6871 (8) c/Å 17.913 (4) β/° 92.557 (8) Volume/Å 3 601.7 (2) Z 2 ρ calc g/cm 3 2.063 µ/mm − 1 1.94 F(000) 374 Crystal size/mm 3 0.05 × 0.03 × 0.02 Radiation Mo Kα, λ = 0.71073 θ range (°) 2.3–28.3 Reflections collected 3835 Independent reflections 1510 R[F2 > 2σ(F2)] 0.037 wR ( F 2) 0.073 S 1.11 2.4. In Silico Studies Molecular docking was employed to estimate the binding affinity between the ligand and the DNA target, as well as to identify possible binding sites. The simulations were conducted using AutoDock Vina. The crystal structure of B-DNA (PDB ID: 1BNA) was retrieved from the Protein Data Bank ( https://www.rcsb.org/ ). Prior to docking, the DNA structure was prepared by eliminating water molecules and non-standard residues to obtain a clean receptor model. Polar hydrogen atoms and Kollman partial charges were subsequently added using AutoDock Tools 1.5.6 [ 17 ]. Both the receptor and ligand structures were converted into the PDBQT file format via AutoDock Tools, ensuring compatibility with AutoDockVina. A grid box encompassing the binding region was defined in such a way that it allowed free rotation and flexible placement of the ligand within the DNA groove. The coordinates and dimensions of the grid box were recorded and incorporated into the configuration file required for docking. AutoDock Vina utilizes a scoring function based on a Lamarckian genetic algorithm to predict the optimal binding poses and their associated free binding energies. Among the multiple docking conformations generated, those with the lowest binding energy were selected for further analysis. Discovery Studio Visualizer 2021 [ 18 ] was employed to analyze and visualize the molecular interactions between the ligand and DNA target. 3. Results and Discussion Previously, we reported that the reaction between bis(hydrogen maleinate)tetrahydrate Co(II) and Mn(II) acetate yielded a three-dimensional coordination polymer, [Co х Mn 1-x (OOCCH = CHCOO).(H 2 O) 2 ] n containing both Co(II) and Mn(II) ions[ 13 ]. In the present work, we demonstrate that under alkaline conditions, maleic acid reacts with copper(II) chloride to form a polymeric heterometallic complex, Na₂[Cu(C₄H₂O₄)₂]·xH₂O. Elemental analysis confirmed the composition Na₂[Cu(C₄H₂O₄)₂]·xH₂O, indicating a 1:1 complex between Cu²⁺ and the maleinate anion, with two coordinated water molecules. The IR spectrum shows asymmetric and symmetric carboxylate ν as (COO⁻)/ν s (COO⁻) stretching bands at 1592 and 1410 cm⁻¹, respectively. The frequency difference (Δν ≈ 180 cm⁻¹) is characteristic of bidentate chelation of carboxylate groups, typical for complexes of dicarboxylic acids[ 19 – 20 ] (see Fig. 1 ). The IR spectrum thus confirms the chelating bidentate coordination mode of the dicarboxylate ligand. In the UV region, bands corresponding to ligand-centered intramolecular transitions are observed, while in the visible region, a broad absorption band is associated with d–d transitions of Cu(II), supporting the formation of an octahedral coordination environment around the copper ion. In the electronic spectrum of the polymeric heterometallic complex in a methanolic solution, a broad band appears around 740 nm, corresponding to the d–d transitions of the Cu²⁺ ion in a distorted octahedral environment (Fig. 2 ). This feature is attributed to the Jahn–Teller effect, which is characteristic of Cu(II) complexes[ 21 , 22 ]. .In the ultraviolet region, a ligand-centered absorption band is observed at approximately 238 nm, attributed to π→π* transitions within the conjugated system involving the carboxylate groups[ 23 ] . The EPR spectrum of the Cu(II)–maleinate complex, recorded at room temperature in the solid state, exhibits an anisotropic signal characteristic of Cu²⁺ ions with a d 9 electronic configuration[ 24 – 25 ].The spectrum includes a pronounced absorption maximum at g ‖ ≈ 2.22 and a minimum at g ⊥ ≈ 2.07, indicating axial symmetry of the copper environment in the complex. These g-factor values are consistent with a square-pyramidal or distorted octahedral coordination, where the z-axis is the elongation direction(Fig. 3 ). The presence of a single clear multiplet without resolved hyperfine splitting suggests weak hyperfine interaction between the unpaired electron of copper and the 63/65 Cu nucleus (I = 3/2), which can be attributed to partial signal averaging or broad line widths. This also implies a relatively symmetric electron density distribution around the copper atom and weak spin density on the ligands . These EPR spectral parameters align well with literature data for Cu(II) complexes with O,Odonor ligands like maleinate anions coordinated in the equatorial plane . 3.1. Structural Features Considering the spectral data and analogies with known structures, it is proposed that the maleinate ligand coordinates via both carboxyl groups, thus forming a five-membered chelate ring[ 12 ]. Two additional water molecules complete the coordination sphere of the copper(II) ion. X-ray crystallography confirmed the formulation Na₂[Cu(C₄H₂O₄)₂]·xH₂O and revealed that the central Cu²⁺ ion is in a distorted octahedral geometry. The maleinate ion acts as a bidentate chelator, coordinating through two carboxylate oxygens to form a stable five-membered ring. Two water molecules complete the coordination sphere of the Cu center, yielding a [Cu(C₄H₂O₄)(H₂O)₂]⁻ unit (see Fig. 4 ). The formation of a five-membered chelate ring by carboxylate ligands is well-documented in copper(II) complexes, often resulting in distorted octahedral or square-pyramidal geometries depending on axial ligation . Sodium cations (Na⁺) do not participate in the first coordination sphere of copper but play a crucial role in stabilizing the crystalline packing. Each Na⁺ ion is coordinated with several oxygen atoms: from the carboxyl groups of the maleinate and from water molecules. These interactions form a spatial hydrogen-bonded network that unites individual complexes into a three-dimensional structure. A similar role of alkali metals in the crystalline structures of complex compounds of dicarboxylic acids is known from the literature [ 5 ], where they provide additional stability through ion-dipole interactions and hydrogen bonds. According to X-ray crystallographic analysis, the compound C₈H₈CuNa₂O₁₀ crystallizes in the monoclinic system, space group P2₁/n, with two formula units per unit cell (Z = 2). The asymmetric part of the structure includes one copper(II) ion, two sodium ions, and an organic ligand coordinated through oxygen atoms. The copper (Cu²⁺) ion is located at the inversion center and has a planar square coordination geometry formed by two equivalent oxygen atoms from two carboxyl groups (O1 and O3, with centrosymmetric arrangement). The Cu1–O1 and Cu1–O3 bond lengths are 1.957(2) Å and 1.922(2) Å, respectively, with O–Cu–O angles close to 90° and 180°, which is characteristic of an ideal planar square environment(Table 2 ). Table 2 Bond lengths [Å] and angles [°] for Na₂[Cu(C₄H₂O₄)₂]·xH₂O С1-O2 1.234(3) Na1-O5-H5 85.0 C1-O1 1.281(3) Na1 i -C4-O3-Cu1 -126.89(19) C3-H3 0.9300 Na1 i -C4-O3-Na1 ii 87.44(10) C4-O4 1.231(3) O4-C4-O3-Na1 i -22.4(2) C4-O3 1.286(3) C3-C4-O3-Na1 i 161.0(2) C4-Na1 2.992(3) O3-C4-O4-Na1 -116.8(3) Na1-O4 2.336(2) C3-C4-O4-Na1 59.9(5) Na1—O5Ф 2.406(2) Na1 i C4-O4-Na1 -141.5(4) Na1-O1 2.800(2) O3-C4-O4-Na1 i -158.60(19) Cu(1)-O3 1.9223(18) Cu(1)-O1 1.9573(18) O5-H5 0.8500 O5-Na1-Na1 139.88(5) O3-Na1-Na1 131.09(5) O4-Na1-Na1 65.56(6) O4-Na1-O5 97.76(8) O4-Na1-O3 113.25(8) O4-Na1-O4 74.54(7) O5-Na1-O4 105.61(8) O5-Na1-Na1 ii 139.28(5) Symmetry codes: (i) − x + 1, − y + 1, − z + 1; (ii) x , y − 1, z ; (iii) − x + 1, − y , − z + 1; (iv) x − 1, y , z ; (v) x , y + 1, z ; (vi) − x + 2, − y , − z + 1; (vii) x + 1, y , z . Sodium ions exhibit a semi-coordinated environment involving oxygens from carboxyl groups and oxygen atoms of other neighboring molecules, forming an extended network of coordination interactions. The Na–O bond lengths range from 2.336(2) to 2.800(2) Å. Multiple interionic Na···Na distances around 3.69 Å are present, which is typical for polymeric sodium-containing complexes [ 26 – 27 ]. The organic ligand is nearly planar, facilitating effective coordination both to the copper ion and to sodium ions. Bond lengths in the carboxyl groups, such as C1–O1 = 1.281(3) Å and C1–O2 = 1.234(3) Å, indicate delocalization of electron density and resonance nature of the bonding. Molecular packing is stabilized by a system of hydrogen bonds between carboxyl and hydroxyl groups, as well as involving coordinated water molecules, forming a three-dimensional supramolecular network. Measurements were performed at room temperature (293 K) using Mo Kα radiation (λ = 0.71073 Å). The structure was refined by least-squares method on F², resulting in R = 0.037, wR = 0.073, and S = 1.11 for 1241 reflections with I > 2σ(I). Maximum and minimum residual electron densities are + 0.38 eÅ⁻³ and − 0.39 eÅ⁻³, respectively, indicating good model quality. Molecular Docking Results The molecular docking study between the polymeric copper(II) complex with maleic acid and the B-DNA dodecamer (PDB ID: 1BNA) revealed a favorable binding affinity, as evidenced by a docking score of − 10.2 kcal/mol. The complex forms conventional hydrogen bonds with the DNA, indicating a strong and specific interaction profile (Table 3 ). Notably, hydrogen bonding occurs between the ligand and several guanine and cytosine bases, including interactions with the O2 atom of cytosine (DC21) and the O4' atom of guanine (DG24), as well as the hydrogen atoms of guanine bases DG2, DG4, and DG22. The hydrogen bond distances range from 2.10 to 2.89 Å, suggesting the formation of stable, directional interactions that are typically indicative of biologically meaningful binding. Several of these interactions occur within or near the minor groove of the DNA helix, implying a potential groove-binding mode of the complex. Additionally, the presence of an intramolecular hydrogen bond within the ligand suggests conformational stability, which may further enhance its DNA-binding capability. Altogether, these findings suggest that the polymeric copper(II) complex exhibits a strong affinity for B-DNA, likely contributing to biological activity through DNA recognition or modulation. The molecular docking between the polymeric copper(II) complex with maleic acid and DNA is given in Fig. 5a, the hydrogen bond interaction map is given in Fig. 5b, and the 2D view of the interactions is given in Fig. 5c. Table 3 Summary of Molecular Docking Results: the polymeric copper(II) complex with maleic acid and DNA (PDB ID: 1BNA) Distance Category Types Interacting Residue on DNA Hydrogen Donor/Acceptor Site 2,10122 Hydrogen Bond Conventional Hydrogen Bond DC21:O2 H-Acceptor 2,46584 Hydrogen Bond Conventional Hydrogen Bond DG24:O4' H-Acceptor 2,60628 Hydrogen Bond Conventional Hydrogen Bond DG2:H21 H-Donor 2,78374 Hydrogen Bond Conventional Hydrogen Bond DG2:H22 H-Donor 2,88637 Hydrogen Bond Conventional Hydrogen Bond DG4:H21 H-Donor 2,71917 Hydrogen Bond Conventional Hydrogen Bond DG22:H21 H-Donor 4. Conclusion A new copper(II) coordination polymer complex with a maleate ligand was synthesized and characterized based on copper chloride Na₂[Cu(C₄H₂O₄)₂]·xH₂O. The study revealed that maleic acid coordinates to the copper ion in a bidentate manner, forming a stable chelate structure. X-ray crystallographic analysis confirmed that the structure is further stabilized by sodium ions, which participate in secondary coordination with carboxyl groups and water molecules. The resulting complex is of interest for further studies on coordination compounds with π-conjugated dicarboxylic acids and their potential applications in materials science, catalysis, and coordination polymerization. The docking analysis revealed that the complex formed conventional hydrogen bonds with nucleotide residues located primarily within the minor groove of the DNA duplex. Key interactions were observed between the ligand and guanine and cytosine bases, particularly involving residues DG2, DC21, and DG24. Hydrogen bond distances ranged from 2.10 Å to 2.89 Å, indicating strong and directional binding, likely contributing to the stability of the complex–DNA association. The overall binding energy of − 10.2 kcal/mol supports a high binding affinity, suggesting that the polymeric Cu(II) complex could potentially interfere with DNA function through groove binding or sequence-selective recognition. Declarations DISCLOSURE STATEMENT No potential conflict of interest was reported by the authors Acknowledgements This work was carried out under the research program of the Ministry of Science and Education at the Institute of Catalysis and Inorganic Chemistry named after Academician M. Nagiev (State Registration No. 0115). The authors acknowledge to Scientific and Technological Research Application and Research Center, Sinop University, Turkey, for the use of the Bruker D8 QUEST diffractometer. CCDC- 2465966 contain the supplementary crystallographic data for this paper. These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via [email protected] or http://www.ccdc.cam.ac.uk/data_request/cif). Author contributions G.E. synthesized the ingredients. She participated in the discussion of the article. M.A. participated in the organization and discussion of the article. R.I. participated in the organization and discussion of the article. B.M. Participated in drawing infrared spectra. B.Y. He played a role in drawing electronic spectra. F.E.O . conducted molecular docking studies. O.Sh. Performed single-crystal X-ray diffraction analysis .M.B. played a role in drawing EPR spectra. Competing interests The authors declare no competing interests. Funding No funding was received for conducting this study. References Kaim W., Schwederski B. Bioinorganic Chemistry: Inorganic Elements in the Chemistry of Life . Wiley, (2013). Baren, E. J. Copper(II) complexes with biologically active ligands. Coordination Chemistry Reviews , (2000), 204:115–171. Lippard, S. J.; Berg, J. M. Principles of Bioinorganic Chemistry ; University Science Books: Mill Valley, CA, USA, (1994). Zhang H. et al. 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Inorganic Chemistry Communications. (2003). 6: 1311–1314 Additional Declarations No competing interests reported. Supplementary Files SUPPLEMENTARYINFORMATION.doc Cite Share Download PDF Status: Published Journal Publication published 04 Dec, 2025 Read the published version in Transition Metal Chemistry → Version 1 posted Editorial decision: Revision requested 19 Jul, 2025 Editor assigned by journal 19 Jul, 2025 Submission checks completed at journal 19 Jul, 2025 First submitted to journal 16 Jul, 2025 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. 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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-7140677","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":487802560,"identity":"1d5521e5-1e3e-45d1-b539-8e4adea5903f","order_by":0,"name":"Esmira Arif Aga Guliyeva","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABDklEQVRIiWNgGAWjYJCCA2CSnbEBRMnxswPphAJitDBDtBhL9gD5CQbE2MUMoRINbiQAKTxa+PlPJx6uqGGQ3XCYuU3iY5tdguTM14kfHhgw5BscwK5FckbuhoNnjjEYbzjM2CY5sy05j186d7ME0GGWG3BoMbjBu+FgAxtDIkiLNM8Z5mLJ2bkbQFoMcNlif/4sUMs/qJY/Z+oTN9w8u/kHPi0GDECHNbZBtTBUHE7ccIN3G15bJG6AtPRJGM88zNhs2VNxHBjIudssEgwkDCRxaOHvP7v5Y8M3G9m+4+0Pb/wwqAZG5dnNN39U2Bjw4dACswwUjywSyCJ41YMASAvzB4LKRsEoGAWjYEQCADi8Y4VHF+wSAAAAAElFTkSuQmCC","orcid":"","institution":"Acad. M. Nagiyev Institute of Catalysis and Inorganic Chemistry Ministry of Science and Education of the Republic of Azerbaijan H. Javid ave","correspondingAuthor":true,"prefix":"","firstName":"Esmira","middleName":"Arif Aga","lastName":"Guliyeva","suffix":""},{"id":487802561,"identity":"2bc0ee31-f57f-4520-a79a-4ae3201e5730","order_by":1,"name":"Ajdar Akper Mejidov","email":"","orcid":"","institution":"Acad. M. Nagiyev Institute of Catalysis and Inorganic Chemistry Ministry of Science and Education of the Republic of Azerbaijan H. Javid ave","correspondingAuthor":false,"prefix":"","firstName":"Ajdar","middleName":"Akper","lastName":"Mejidov","suffix":""},{"id":487802562,"identity":"4ff55c96-0113-4b37-8180-e3c526a634ab","order_by":2,"name":"Rayyat Huseyn Ismayilov","email":"","orcid":"","institution":"Acad. M. Nagiyev Institute of Catalysis and Inorganic Chemistry Ministry of Science and Education of the Republic of Azerbaijan H. Javid ave","correspondingAuthor":false,"prefix":"","firstName":"Rayyat","middleName":"Huseyn","lastName":"Ismayilov","suffix":""},{"id":487802563,"identity":"fdfda93a-f0e9-4357-a01b-9477b10644aa","order_by":3,"name":"Malahat Bagiyeva Rustam","email":"","orcid":"","institution":"State University Azerbaijan","correspondingAuthor":false,"prefix":"","firstName":"Malahat","middleName":"Bagiyeva","lastName":"Rustam","suffix":""},{"id":487802564,"identity":"a5b72a69-8dba-4b82-8862-3ec56a68a966","order_by":4,"name":"Bahattin Yalcin","email":"","orcid":"","institution":"Marmara University","correspondingAuthor":false,"prefix":"","firstName":"Bahattin","middleName":"","lastName":"Yalcin","suffix":""},{"id":487802565,"identity":"cf94e44e-8475-4ed4-aed6-e2ac708068af","order_by":5,"name":"Füreya Elif Öztürkkan","email":"","orcid":"","institution":"Kafkas University","correspondingAuthor":false,"prefix":"","firstName":"Füreya","middleName":"Elif","lastName":"Öztürkkan","suffix":""},{"id":487802566,"identity":"15b56b3e-2a67-47bb-b27d-3c7767f18283","order_by":6,"name":"Onur Shahin","email":"","orcid":"","institution":"Marmara University","correspondingAuthor":false,"prefix":"","firstName":"Onur","middleName":"","lastName":"Shahin","suffix":""},{"id":487802567,"identity":"288fd246-5c05-44cc-8613-6891c6e6ebe6","order_by":7,"name":"Mahammad Allahverdi Bayramov","email":"","orcid":"","institution":"Institute of Radiation Problems","correspondingAuthor":false,"prefix":"","firstName":"Mahammad","middleName":"Allahverdi","lastName":"Bayramov","suffix":""}],"badges":[],"createdAt":"2025-07-16 13:53:14","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7140677/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7140677/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s11243-025-00705-y","type":"published","date":"2025-12-04T15:57:47+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":87556386,"identity":"2255c1eb-7e2c-4e7c-a35d-f25b7b4e9959","added_by":"auto","created_at":"2025-07-25 07:11:12","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":44142,"visible":true,"origin":"","legend":"\u003cp\u003eIR spectrum of heterometallic polymer complex Na₂[Cu(C₄H₂O₄)₂]·xH₂O\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-7140677/v1/5388cad75b8d2fe83cf74646.png"},{"id":87556389,"identity":"543d0808-d62e-4c09-854d-3c8cedce1aed","added_by":"auto","created_at":"2025-07-25 07:11:12","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":41763,"visible":true,"origin":"","legend":"\u003cp\u003eElectronic absorption spectra of the heterometallic polymeric complex Na₂[Cu(C₄H₂O₄)₂]·xH₂O in methanol: (a) visible region, (b) UV region.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7140677/v1/b180e5b422d7efa2b679a03a.png"},{"id":87556534,"identity":"443ca69a-77ca-4277-92ba-124cb0810f7c","added_by":"auto","created_at":"2025-07-25 07:19:12","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":28394,"visible":true,"origin":"","legend":"\u003cp\u003eEPR Spectrum of the Heterometallic Polymer Complex Na₂[Cu(C₄H₂O₄)₂]·xH₂O\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-7140677/v1/9e95b78da9a0228026303501.png"},{"id":87556533,"identity":"3d37597a-a761-4f1e-bc9a-ed17d91d8d7e","added_by":"auto","created_at":"2025-07-25 07:19:12","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":40413,"visible":true,"origin":"","legend":"\u003cp\u003eMolecular structure of the complex Na₂[Cu(C₄H₂O₄)₂]·xH₂O\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-7140677/v1/53f6a1b1b46e163b8a7c1709.png"},{"id":87556535,"identity":"332eae4e-8e77-4bfa-9d20-36c4a17a435e","added_by":"auto","created_at":"2025-07-25 07:19:12","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":402393,"visible":true,"origin":"","legend":"\u003cp\u003eMolecular docking between the polymeric copper(II) complex with maleic acid and DNA (PDB ID: 1BNA) (a), Hydrogen bond interaction map between the polymeric copper(II) complex with maleic acid and DNA (PDB ID: 1BNA) (b), 2D view of the interactions between the polymeric copper(II) complex with maleic acid and DNA (PDB ID: 1BNA) (c)\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-7140677/v1/bccb7f853bb9259c11ce618b.png"},{"id":97723869,"identity":"f8ee022a-d625-4744-992f-03a54c5343c5","added_by":"auto","created_at":"2025-12-08 16:08:53","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1263723,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7140677/v1/aab208a7-cb8d-4de1-b134-c57f0dae7df1.pdf"},{"id":87556410,"identity":"285c4bb3-8a44-420c-b14f-b8f0e2c48cbf","added_by":"auto","created_at":"2025-07-25 07:11:13","extension":"doc","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":865792,"visible":true,"origin":"","legend":"","description":"","filename":"SUPPLEMENTARYINFORMATION.doc","url":"https://assets-eu.researchsquare.com/files/rs-7140677/v1/b11b1735541cc84de36207a7.doc"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eSynthesis, Structure, and Properties of a Polymer Complex of Copper(II) With Maleic Acid\u003c/p\u003e","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eCoordination compounds of copper(II) are of significant interest due to their structural diversity, catalytic activity, photochemical properties, and biological relevance [\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Cu(II) complexes play important roles in fields such as the development of functional materials, catalyst synthesis, and the creation of antibacterial and anticancer agents. Special attention is given to complexes featuring organic acids with multiple coordination sites, particularly dicarboxylic acids.\u003c/p\u003e\u003cp\u003eMaleic acid (cisbutenedioic acid) is a promising dicarboxylate ligand containing two closely spaced carboxyl groups capable of forming stable chelate complexes with transition metals. Due to its \u003cem\u003ecis\u003c/em\u003e configuration, maleic acid exhibits distinct coordination behavior compared to its \u003cem\u003etrans\u003c/em\u003e isomer, fumaric acid [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. These structural characteristics make maleic acid particularly interesting for the design of novel coordination polymers.\u003c/p\u003e\u003cp\u003eThe biological activity of the copper(II)-maleinate complex arises from both the known antibacterial and antifungal properties of Cu\u0026sup2;⁺ ions and the potential metabolic activity of the maleinate anion, a derivative of maleic acid. Copper(II) acts as an essential cofactor in numerous biological processes, including redox catalysis, electron transport, and the detoxification of reactive oxygen species. Cu(II) complexes are capable of interacting with bacterial proteins, enzymes, and nucleic acids, thereby disrupting their biological functions. Coordination with maleinate helps stabilize the copper ion in a biologically active form and may enhance its permeability across cell membranes[6\u0026ndash;7].\u003c/p\u003e\u003cp\u003eAlthough extensive studies have been conducted on Cu complexes with other dicarboxylates such as fumarate, tartrate, and oxalate [\u003cspan additionalcitationids=\"CR9\" citationid=\"CR7\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e10\u003c/span\u003e], copper maleinate complexes remain underexplored. Available data are fragmentary and mainly concern monomeric complexes or poorly defined coordination environments [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. In our previous work [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e13\u003c/span\u003e], we obtained a polymeric, polynuclear heterometallic maleinate complex of Mn(II) and Co(II), [Co\u003csub\u003eх\u003c/sub\u003eMn\u003csub\u003e1-x\u003c/sub\u003e(OOCCH\u0026thinsp;=\u0026thinsp;CHCOO).(H\u003csub\u003e2\u003c/sub\u003eO)\u003csub\u003e2\u003c/sub\u003e]\u003csub\u003en\u003c/sub\u003e by reacting mononuclear bismaleinate tetratedrate cobalt with manganese acetate.\u003c/p\u003e\u003cp\u003eThe present study aims to synthesize a novel polynuclear Cu(II) maleinate complex under alkaline conditions and to comprehensively characterize its structure Na₂[Cu(C₄H₂O₄)₂]\u0026middot;xH₂O. Particular focus is placed on elucidating the coordination environment of the Cu ion and the spatial organization of the polymeric matrix. Characterization methods include IR and UV\u0026ndash;visible spectroscopy, elemental analysis, thermogravimetric analysis, and X-ray single crystal diffraction, providing an integrated picture of the complex\u0026rsquo;s structure. The results expand our understanding of πconjugated dicarboxylate coordination possibilities and their potential in the development of new transition-metal\u0026ndash;based materials.\u003c/p\u003e"},{"header":"2. Experimental","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e2.1. General and spectroscopic measurements\u003c/h2\u003e\u003cp\u003eAll chemicals were used as received without further purification. Copper(II) chloride, maleic acid (C\u003csub\u003e4\u003c/sub\u003eH\u003csub\u003e4\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e), and sodium hydroxide (NaOH) were of analytical grade (SigmaAldrich). FT-IR spectra of samples in vaseline oil were recorded in the range 4000\u0026ndash;400 cm⁻\u0026sup1; using a Nicolet IS10 spectrophotometer. Electronic absorption spectra were obtained with a SPECORD 50 spectrophotometer in aqueous solution over the UV range (200\u0026ndash;400 nm) and visible region (400\u0026ndash;1100 nm). Thermogravimetric analysis (TGA) was performed using a NETZSCH STA 449 F3 derivateograph under an inert atmosphere. Elemental analysis was carried out at the Tubitak Analytical Laboratory (Ankara) using a LECO CHNS 932 analyzer.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e2.2. Synthesis of Na₂[Cu(C₄H₂O₄)₂]\u0026middot;xH₂O\u003c/h2\u003e\u003cp\u003eCopper(II) chloride (0.199 g, 1 mmol) was dissolved in 20 mL of water. To this solution, maleic acid (0.232 g, 2 mmol) was added and stirred at ambient temperature. The pH was adjusted to 6.0 using a NaOH solution. The resulting mixture was left undisturbed for 4\u0026ndash;5 days, during which blue crystals (melting point\u0026thinsp;\u0026gt;\u0026thinsp;250\u0026deg;C) formed. The crystals were filtered and dried in vacuo at room temperature, yielding 0.75 g (80%).For C₈H₈CuNa₂O₁₀: calculated: C 25.66%, H 2.13%, Cu 17.11%, Na 12.30%; found: C 25.70%, H 2.10%, Cu 17.18%, Na 12.25%.IR (ν, cm⁻\u0026sup1;): ν\u003csub\u003eas\u003c/sub\u003e(COO⁻) 1500, 1590; ν\u003csub\u003es\u003c/sub\u003e(COO⁻) 1400, 1420.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\u003ch2\u003e2.3. Crystal Structure Determination\u003c/h2\u003e\u003cp\u003eSingle-crystal X-ray diffraction was performed on a Bruker APEX-3 CCD diffractometer using monochromatized Mo Kα radiation (λ\u0026thinsp;=\u0026thinsp;0.71073 \u0026Aring;) at 293 K [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. The empirical formula is C₈H₈CuNa₂O₁₀; (FW\u0026thinsp;=\u0026thinsp;373.63). Unit cell parameters: a\u0026thinsp;=\u0026thinsp;9.119(2) \u0026Aring;, b\u0026thinsp;=\u0026thinsp;3.6871(8) \u0026Aring;, c\u0026thinsp;=\u0026thinsp;17.913(4) \u0026Aring;, β\u0026thinsp;=\u0026thinsp;92.557(8)\u0026deg;, V\u0026thinsp;=\u0026thinsp;601.7(2) \u0026Aring;\u0026sup3;. Structure solution was done using SHELXS [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e15\u003c/span\u003e], and refinement using SHELXL [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e16\u003c/span\u003e] via least-squares on F\u0026sup2;. The refinement converged with R\u0026thinsp;=\u0026thinsp;0.037, wR\u0026thinsp;=\u0026thinsp;0.073, S\u0026thinsp;=\u0026thinsp;1.11 for 1241 reflections with I\u0026thinsp;\u0026gt;\u0026thinsp;2σ(I). The maximum and minimum residual electron densities are +\u0026thinsp;0.38 and \u0026minus;\u0026thinsp;0.39 e\u0026middot;\u0026Aring;⁻\u0026sup3;, indicating a high-quality model. CIF preparation and structural visualization were completed with WinGX and Mercury. All hydrogen atoms were placed using constraints. The complex exhibits good crystallographic symmetry and stability, making it suitable for diverse chemical investigations. Crystallographic data and refinement details for Na₂[Cu(C₄H₂O₄)₂]\u0026middot;xH₂O are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eCrystallographic data and refinement details for Na₂[Cu(C₄H₂O₄)₂]\u0026middot;xH₂O\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"2\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eEmpirical formula\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eC₈H₈CuNa₂O₁₀\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFormula weight\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e373.66\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTemperature/K\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e293\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCrystal system\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003emonoclinic\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSpace group\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eP2\u003csub\u003e1\u003c/sub\u003e/\u003cem\u003en\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ea/\u0026Aring;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e9.119 (2)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eb/\u0026Aring;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3.6871 (8)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ec/\u0026Aring;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e17.913 (4)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eβ/\u0026deg;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e92.557 (8)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eVolume/\u0026Aring;\u003csup\u003e3\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e601.7 (2)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eZ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eρ\u003csub\u003ecalc\u003c/sub\u003eg/cm\u003csup\u003e3\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2.063\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026micro;/mm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1.94\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eF(000)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e374\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCrystal size/mm\u003csup\u003e3\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.05 \u0026times; 0.03 \u0026times; 0.02\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eRadiation\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMo Kα, λ\u0026thinsp;=\u0026thinsp;0.71073\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eθ range (\u0026deg;)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2.3\u0026ndash;28.3\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eReflections collected\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3835\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eIndependent reflections\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1510\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eR[F2\u0026thinsp;\u0026gt;\u0026thinsp;2σ(F2)]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.037\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003ewR\u003c/em\u003e(\u003cem\u003eF\u003c/em\u003e2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.073\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eS\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1.11\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\u003ch2\u003e2.4. \u003cem\u003eIn Silico\u003c/em\u003e Studies\u003c/h2\u003e\u003cp\u003eMolecular docking was employed to estimate the binding affinity between the ligand and the DNA target, as well as to identify possible binding sites. The simulations were conducted using AutoDock Vina. The crystal structure of B-DNA (PDB ID: 1BNA) was retrieved from the Protein Data Bank (\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.rcsb.org/\u003c/span\u003e\u003cspan address=\"https://www.rcsb.org/\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e). Prior to docking, the DNA structure was prepared by eliminating water molecules and non-standard residues to obtain a clean receptor model. Polar hydrogen atoms and Kollman partial charges were subsequently added using AutoDock Tools 1.5.6 [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Both the receptor and ligand structures were converted into the PDBQT file format via AutoDock Tools, ensuring compatibility with AutoDockVina. A grid box encompassing the binding region was defined in such a way that it allowed free rotation and flexible placement of the ligand within the DNA groove. The coordinates and dimensions of the grid box were recorded and incorporated into the configuration file required for docking. AutoDock Vina utilizes a scoring function based on a Lamarckian genetic algorithm to predict the optimal binding poses and their associated free binding energies. Among the multiple docking conformations generated, those with the lowest binding energy were selected for further analysis. Discovery Studio Visualizer 2021 [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e18\u003c/span\u003e] was employed to analyze and visualize the molecular interactions between the ligand and DNA target.\u003c/p\u003e\u003c/div\u003e"},{"header":"3. Results and Discussion","content":"\u003cp\u003ePreviously, we reported that the reaction between bis(hydrogen maleinate)tetrahydrate Co(II) and Mn(II) acetate yielded a three-dimensional coordination polymer, [Co\u003csub\u003eх\u003c/sub\u003eMn\u003csub\u003e1-x\u003c/sub\u003e(OOCCH\u0026thinsp;=\u0026thinsp;CHCOO).(H\u003csub\u003e2\u003c/sub\u003eO)\u003csub\u003e2\u003c/sub\u003e]\u003csub\u003en\u003c/sub\u003e containing both Co(II) and Mn(II) ions[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. In the present work, we demonstrate that under alkaline conditions, maleic acid reacts with copper(II) chloride to form a polymeric heterometallic complex, Na₂[Cu(C₄H₂O₄)₂]\u0026middot;xH₂O.\u003c/p\u003e\u003cp\u003eElemental analysis confirmed the composition Na₂[Cu(C₄H₂O₄)₂]\u0026middot;xH₂O, indicating a 1:1 complex between Cu\u0026sup2;⁺ and the maleinate anion, with two coordinated water molecules.\u003c/p\u003e\u003cp\u003eThe IR spectrum shows asymmetric and symmetric carboxylate ν\u003csub\u003eas\u003c/sub\u003e(COO⁻)/ν\u003csub\u003es\u003c/sub\u003e(COO⁻) stretching bands at 1592 and 1410 cm⁻\u0026sup1;, respectively. The frequency difference (Δν\u0026thinsp;\u0026asymp;\u0026thinsp;180 cm⁻\u0026sup1;) is characteristic of bidentate chelation of carboxylate groups, typical for complexes of dicarboxylic acids[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e20\u003c/span\u003e] (see Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThe IR spectrum thus confirms the chelating bidentate coordination mode of the dicarboxylate ligand.\u003c/p\u003e\u003cp\u003eIn the UV region, bands corresponding to ligand-centered intramolecular transitions are observed, while in the visible region, a broad absorption band is associated with d\u0026ndash;d transitions of Cu(II), supporting the formation of an octahedral coordination environment around the copper ion.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eIn the electronic spectrum of the polymeric heterometallic complex in a methanolic solution, a broad band appears around 740 nm, corresponding to the \u003cem\u003ed\u0026ndash;d\u003c/em\u003e transitions of the Cu\u0026sup2;⁺ ion in a distorted octahedral environment (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). This feature is attributed to the Jahn\u0026ndash;Teller effect, which is characteristic of Cu(II) complexes[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. .In the ultraviolet region, a ligand-centered absorption band is observed at approximately 238 nm, attributed to π\u0026rarr;π* transitions within the conjugated system involving the carboxylate groups[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e23\u003c/span\u003e] .\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe EPR spectrum of the Cu(II)\u0026ndash;maleinate complex, recorded at room temperature in the solid state, exhibits an anisotropic signal characteristic of Cu\u0026sup2;⁺ ions with a d\u003csup\u003e9\u003c/sup\u003e electronic configuration[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e25\u003c/span\u003e].The spectrum includes a pronounced absorption maximum at g\u003csub\u003e‖\u003c/sub\u003e \u0026asymp; 2.22 and a minimum at g\u003csub\u003e\u0026perp;\u003c/sub\u003e \u0026asymp; 2.07, indicating axial symmetry of the copper environment in the complex. These g-factor values are consistent with a square-pyramidal or distorted octahedral coordination, where the z-axis is the elongation direction(Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThe presence of a single clear multiplet without resolved hyperfine splitting suggests weak hyperfine interaction between the unpaired electron of copper and the \u003csup\u003e63/65\u003c/sup\u003eCu nucleus (I\u0026thinsp;=\u0026thinsp;3/2), which can be attributed to partial signal averaging or broad line widths. This also implies a relatively symmetric electron density distribution around the copper atom and weak spin density on the ligands .\u003c/p\u003e\u003cp\u003eThese EPR spectral parameters align well with literature data for Cu(II) complexes with O,Odonor ligands like maleinate anions coordinated in the equatorial plane .\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003e3.1. Structural Features\u003c/h2\u003e\u003cp\u003eConsidering the spectral data and analogies with known structures, it is proposed that the maleinate ligand coordinates via both carboxyl groups, thus forming a five-membered chelate ring[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Two additional water molecules complete the coordination sphere of the copper(II) ion.\u003c/p\u003e\u003cp\u003eX-ray crystallography confirmed the formulation Na₂[Cu(C₄H₂O₄)₂]\u0026middot;xH₂O and revealed that the central Cu\u0026sup2;⁺ ion is in a distorted octahedral geometry. The maleinate ion acts as a bidentate chelator, coordinating through two carboxylate oxygens to form a stable five-membered ring. Two water molecules complete the coordination sphere of the Cu center, yielding a [Cu(C₄H₂O₄)(H₂O)₂]⁻ unit (see Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThe formation of a five-membered chelate ring by carboxylate ligands is well-documented in copper(II) complexes, often resulting in distorted octahedral or square-pyramidal geometries depending on axial ligation .\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eSodium cations (Na⁺) do not participate in the first coordination sphere of copper but play a crucial role in stabilizing the crystalline packing. Each Na⁺ ion is coordinated with several oxygen atoms: from the carboxyl groups of the maleinate and from water molecules. These interactions form a spatial hydrogen-bonded network that unites individual complexes into a three-dimensional structure.\u003c/p\u003e\u003cp\u003eA similar role of alkali metals in the crystalline structures of complex compounds of dicarboxylic acids is known from the literature [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e], where they provide additional stability through ion-dipole interactions and hydrogen bonds.\u003c/p\u003e\u003cp\u003eAccording to X-ray crystallographic analysis, the compound C₈H₈CuNa₂O₁₀ crystallizes in the monoclinic system, space group P2₁/n, with two formula units per unit cell (Z\u0026thinsp;=\u0026thinsp;2). The asymmetric part of the structure includes one copper(II) ion, two sodium ions, and an organic ligand coordinated through oxygen atoms.\u003c/p\u003e\u003cp\u003eThe copper (Cu\u0026sup2;⁺) ion is located at the inversion center and has a planar square coordination geometry formed by two equivalent oxygen atoms from two carboxyl groups (O1 and O3, with centrosymmetric arrangement). The Cu1\u0026ndash;O1 and Cu1\u0026ndash;O3 bond lengths are 1.957(2) \u0026Aring; and 1.922(2) \u0026Aring;, respectively, with O\u0026ndash;Cu\u0026ndash;O angles close to 90\u0026deg; and 180\u0026deg;, which is characteristic of an ideal planar square environment(Table \u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eBond lengths [\u0026Aring;] and angles [\u0026deg;] for Na₂[Cu(C₄H₂O₄)₂]\u0026middot;xH₂O\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eС1-O2\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1.234(3)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNa1-O5-H5\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003e85.0\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eC1-O1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e1.281(3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNa1\u003csup\u003e\u003cem\u003ei\u003c/em\u003e\u003c/sup\u003e-C4-O3-Cu1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-126.89(19)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eC3-H3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0.9300\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNa1\u003csup\u003e\u003cem\u003ei\u003c/em\u003e\u003c/sup\u003e-C4-O3-Na1\u003csup\u003e\u003cem\u003eii\u003c/em\u003e\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e87.44(10)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eC4-O4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e1.231(3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eO4-C4-O3-Na1\u003csup\u003e\u003cem\u003ei\u003c/em\u003e\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-22.4(2)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eC4-O3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e1.286(3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eC3-C4-O3-Na1\u003csup\u003e\u003cem\u003ei\u003c/em\u003e\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e161.0(2)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eC4-Na1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e2.992(3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eO3-C4-O4-Na1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-116.8(3)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNa1-O4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e2.336(2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eC3-C4-O4-Na1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e59.9(5)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNa1\u0026mdash;O5Ф\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e2.406(2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNa1\u003csup\u003e\u003cem\u003ei\u003c/em\u003e\u003c/sup\u003eC4-O4-Na1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-141.5(4)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNa1-O1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e2.800(2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eO3-C4-O4-Na1\u003csup\u003e\u003cem\u003ei\u003c/em\u003e\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e-158.60(19)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCu(1)-O3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e1.9223(18)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCu(1)-O1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e1.9573(18)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eO5-H5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e0.8500\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eO5-Na1-Na1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e139.88(5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eO3-Na1-Na1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e131.09(5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eO4-Na1-Na1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e65.56(6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eO4-Na1-O5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e97.76(8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eO4-Na1-O3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e113.25(8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eO4-Na1-O4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e74.54(7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eO5-Na1-O4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e105.61(8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eO5-Na1-Na1\u003csup\u003e\u003cem\u003eii\u003c/em\u003e\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e139.28(5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eSymmetry codes: (i)\u0026thinsp;\u0026minus;\u0026thinsp;\u003cem\u003ex\u003c/em\u003e\u0026thinsp;+\u0026thinsp;1, \u0026minus;\u003cem\u003ey\u003c/em\u003e\u0026thinsp;+\u0026thinsp;1, \u0026minus;\u003cem\u003ez\u003c/em\u003e\u0026thinsp;+\u0026thinsp;1; (ii) \u003cem\u003ex\u003c/em\u003e, \u003cem\u003ey\u003c/em\u003e\u0026thinsp;\u0026minus;\u0026thinsp;1, \u003cem\u003ez\u003c/em\u003e; (iii)\u0026thinsp;\u0026minus;\u0026thinsp;\u003cem\u003ex\u003c/em\u003e\u0026thinsp;+\u0026thinsp;1, \u0026minus;\u003cem\u003ey\u003c/em\u003e, \u0026minus;\u003cem\u003ez\u003c/em\u003e\u0026thinsp;+\u0026thinsp;1; (iv) \u003cem\u003ex\u003c/em\u003e\u0026thinsp;\u0026minus;\u0026thinsp;1, \u003cem\u003ey\u003c/em\u003e, \u003cem\u003ez\u003c/em\u003e; (v) \u003cem\u003ex\u003c/em\u003e, \u003cem\u003ey\u003c/em\u003e\u0026thinsp;+\u0026thinsp;1, \u003cem\u003ez\u003c/em\u003e; (vi)\u0026thinsp;\u0026minus;\u0026thinsp;\u003cem\u003ex\u003c/em\u003e\u0026thinsp;+\u0026thinsp;2, \u0026minus;\u003cem\u003ey\u003c/em\u003e, \u0026minus;\u003cem\u003ez\u003c/em\u003e\u0026thinsp;+\u0026thinsp;1; (vii) \u003cem\u003ex\u003c/em\u003e\u0026thinsp;+\u0026thinsp;1, \u003cem\u003ey\u003c/em\u003e, \u003cem\u003ez\u003c/em\u003e.\u003c/p\u003e\u003cp\u003eSodium ions exhibit a semi-coordinated environment involving oxygens from carboxyl groups and oxygen atoms of other neighboring molecules, forming an extended network of coordination interactions. The Na\u0026ndash;O bond lengths range from 2.336(2) to 2.800(2) \u0026Aring;. Multiple interionic Na\u0026middot;\u0026middot;\u0026middot;Na distances around 3.69 \u0026Aring; are present, which is typical for polymeric sodium-containing complexes [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e27\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThe organic ligand is nearly planar, facilitating effective coordination both to the copper ion and to sodium ions. Bond lengths in the carboxyl groups, such as C1\u0026ndash;O1\u0026thinsp;=\u0026thinsp;1.281(3) \u0026Aring; and C1\u0026ndash;O2\u0026thinsp;=\u0026thinsp;1.234(3) \u0026Aring;, indicate delocalization of electron density and resonance nature of the bonding.\u003c/p\u003e\u003cp\u003eMolecular packing is stabilized by a system of hydrogen bonds between carboxyl and hydroxyl groups, as well as involving coordinated water molecules, forming a three-dimensional supramolecular network.\u003c/p\u003e\u003cp\u003eMeasurements were performed at room temperature (293 K) using Mo Kα radiation (λ\u0026thinsp;=\u0026thinsp;0.71073 \u0026Aring;). The structure was refined by least-squares method on F\u0026sup2;, resulting in R\u0026thinsp;=\u0026thinsp;0.037, wR\u0026thinsp;=\u0026thinsp;0.073, and S\u0026thinsp;=\u0026thinsp;1.11 for 1241 reflections with I\u0026thinsp;\u0026gt;\u0026thinsp;2σ(I). Maximum and minimum residual electron densities are +\u0026thinsp;0.38 e\u0026Aring;⁻\u0026sup3; and \u0026minus;\u0026thinsp;0.39 e\u0026Aring;⁻\u0026sup3;, respectively, indicating good model quality.\u003c/p\u003e\u003cp\u003e\u003cb\u003eMolecular Docking Results\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe molecular docking study between the polymeric copper(II) complex with maleic acid and the B-DNA dodecamer (PDB ID: 1BNA) revealed a favorable binding affinity, as evidenced by a docking score of \u0026minus;\u0026thinsp;10.2 kcal/mol. The complex forms conventional hydrogen bonds with the DNA, indicating a strong and specific interaction profile (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). Notably, hydrogen bonding occurs between the ligand and several guanine and cytosine bases, including interactions with the O2 atom of cytosine (DC21) and the O4' atom of guanine (DG24), as well as the hydrogen atoms of guanine bases DG2, DG4, and DG22. The hydrogen bond distances range from 2.10 to 2.89 \u0026Aring;, suggesting the formation of stable, directional interactions that are typically indicative of biologically meaningful binding. Several of these interactions occur within or near the minor groove of the DNA helix, implying a potential groove-binding mode of the complex. Additionally, the presence of an intramolecular hydrogen bond within the ligand suggests conformational stability, which may further enhance its DNA-binding capability. Altogether, these findings suggest that the polymeric copper(II) complex exhibits a strong affinity for B-DNA, likely contributing to biological activity through DNA recognition or modulation. The molecular docking between the polymeric copper(II) complex with maleic acid and DNA is given in Fig.\u0026nbsp;5a, the hydrogen bond interaction map is given in Fig.\u0026nbsp;5b, and the 2D view of the interactions is given in Fig.\u0026nbsp;5c.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eSummary of Molecular Docking Results: the polymeric copper(II) complex with maleic acid and DNA (PDB ID: 1BNA)\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eDistance\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCategory\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eTypes\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eInteracting Residue on DNA\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eHydrogen Donor/Acceptor Site\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2,10122\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eHydrogen Bond\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eConventional Hydrogen Bond\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eDC21:O2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eH-Acceptor\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2,46584\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eHydrogen Bond\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eConventional Hydrogen Bond\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eDG24:O4'\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eH-Acceptor\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2,60628\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eHydrogen Bond\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eConventional Hydrogen Bond\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eDG2:H21\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eH-Donor\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2,78374\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eHydrogen Bond\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eConventional Hydrogen Bond\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eDG2:H22\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eH-Donor\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2,88637\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eHydrogen Bond\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eConventional Hydrogen Bond\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eDG4:H21\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eH-Donor\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2,71917\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eHydrogen Bond\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eConventional Hydrogen Bond\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eDG22:H21\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eH-Donor\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e"},{"header":"4. Conclusion","content":"\u003cp\u003eA new copper(II) coordination polymer complex with a maleate ligand was synthesized and characterized based on copper chloride Na₂[Cu(C₄H₂O₄)₂]\u0026middot;xH₂O. The study revealed that maleic acid coordinates to the copper ion in a bidentate manner, forming a stable chelate structure. X-ray crystallographic analysis confirmed that the structure is further stabilized by sodium ions, which participate in secondary coordination with carboxyl groups and water molecules. The resulting complex is of interest for further studies on coordination compounds with π-conjugated dicarboxylic acids and their potential applications in materials science, catalysis, and coordination polymerization. The docking analysis revealed that the complex formed conventional hydrogen bonds with nucleotide residues located primarily within the minor groove of the DNA duplex. Key interactions were observed between the ligand and guanine and cytosine bases, particularly involving residues DG2, DC21, and DG24. Hydrogen bond distances ranged from 2.10 \u0026Aring; to 2.89 \u0026Aring;, indicating strong and directional binding, likely contributing to the stability of the complex\u0026ndash;DNA association. The overall binding energy of \u0026minus;\u0026thinsp;10.2 kcal/mol supports a high binding affinity, suggesting that the polymeric Cu(II) complex could potentially interfere with DNA function through groove binding or sequence-selective recognition.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eDISCLOSURE STATEMENT\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNo potential conflict of interest was reported by the authors\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work was carried out under the research program of the Ministry of Science and Education at the Institute of Catalysis and Inorganic Chemistry named after Academician M. Nagiev (State Registration No. 0115). The authors acknowledge to Scientific and Technological Research Application and Research Center, Sinop University, Turkey, for the use of the Bruker D8 QUEST diffractometer. CCDC- 2465966 contain the supplementary crystallographic data for this paper. These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via [email protected] or http://www.ccdc.cam.ac.uk/data_request/cif).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions\u0026nbsp;\u003c/strong\u003eG.E. synthesized the ingredients. She participated in the discussion of the article. M.A. participated in the organization and discussion of the article. R.I. participated in the organization and discussion of the article. B.M. Participated in drawing infrared spectra. \u0026nbsp;B.Y. He played a role in drawing electronic spectra. F.E.O . conducted molecular docking studies. \u0026nbsp;O.Sh. Performed single-crystal X-ray diffraction analysis .M.B. played a role in drawing EPR spectra.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u0026nbsp;\u003c/strong\u003eThe authors declare no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding \u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNo funding was received for conducting this study.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eKaim W., Schwederski B. \u003cem\u003eBioinorganic Chemistry: Inorganic Elements in the Chemistry of Life\u003c/em\u003e. Wiley, (2013).\u003c/li\u003e\n\u003cli\u003eBaren, E. J. Copper(II) complexes with biologically active ligands. \u003cem\u003eCoordination Chemistry Reviews\u003c/em\u003e, (2000), 204:115\u0026ndash;171.\u003c/li\u003e\n\u003cli\u003eLippard, S. J.; Berg, J. 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J. \u003cem\u003eElectron Paramagnetic Resonance\u003c/em\u003e. Oxford University Press, (1990).\u003c/li\u003e\n\u003cli\u003ePretsch T. et al. Spectral evidence of carboxylate coordination. \u003cem\u003e Acta A\u003c/em\u003e, (2002), 58:101\u0026ndash;109.\u003c/li\u003e\n\u003cli\u003eZhang, C.-H., Chen, Y.-G., Tang, Q., \u0026amp; Liu, S.-X. Polynuclear complexes of main group and transition metals with polyaminopolycarboxylate and polyoxometalate. \u003cem\u003eDalton Trans.\u003c/em\u003e, (2012), 41: 9971\u0026ndash;9980.\u003c/li\u003e\n\u003cli\u003eSutapa Sen, Chirantan Roy Choudhury, Nirmal Kumar Karan, Amitabha Datta, Samiran Mitra, R.K. Bhuban Singh,Volker Gramlich. One novel polynuclear complex [Cu\u003csub\u003e2\u003c/sub\u003e(bpc)\u003csub\u003e2\u003c/sub\u003e(N\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e4\u003c/sub\u003eCa(H\u003csub\u003e2\u003c/sub\u003eO)\u003csub\u003e2\u003c/sub\u003eNa\u003csub\u003e2\u003c/sub\u003e(H\u003csub\u003e2\u003c/sub\u003eO)\u003csub\u003e2\u003c/sub\u003e]\u003csub\u003en\u003c/sub\u003e having three different transition and non-transition metal centres. Inorganic Chemistry Communications. (2003). 6: 1311\u0026ndash;1314\u003c/li\u003e\n\u003c/ol\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"transition-metal-chemistry","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"tmch","sideBox":"Learn more about [Transition Metal Chemistry](http://link.springer.com/journal/11243)","snPcode":"11243","submissionUrl":"https://submission.nature.com/new-submission/11243/3","title":"Transition Metal Chemistry","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"copper(II) complex, maleic acid, copper acetate, coordination chemistry, IR spectroscopy, X-ray crystallography","lastPublishedDoi":"10.21203/rs.3.rs-7140677/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7140677/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eA new polymeric copper(II) complex with maleic acid, used as a dicarboxylate ligand, were synthesized Na₂[Cu(C₄H₂O₄)₂]\u0026middot;xH₂O. The resulting complex was characterized by elemental analysis, infrared and UV\u0026ndash;visible spectroscopy, and X-ray crystallography. Spectroscopic data indicate that the maleinate ion coordinates in a chelating bidentate mode, creating a distorted octahedral coordination environment around Cu(II). X-ray crystallography confirmed the formulation Na₂[Cu(C₄H₂O₄)₂]\u0026middot;xH₂O and revealed that the central Cu\u0026sup2;⁺ ion is in a distorted octahedral geometry. The maleinate ion acts as a bidentate chelator, coordinating through two carboxylate oxygens to form a stable five-membered ring. Two water molecules complete the coordination sphere of the Cu center, yielding a [Cu(C₄H₂O₄)(H₂O)₂]⁻ unit This study extends our understanding of the coordination behavior of π-conjugated dicarboxylic acids with transition-metal ions. Molecular docking studies demonstrated that the polymeric copper(II)\u0026ndash;maleic acid complex exhibited strong binding affinity toward B-DNA (1BNA), with a binding energy of \u0026minus;\u0026thinsp;10.2 kcal/mol and multiple stable hydrogen bond interactions.\u003c/p\u003e","manuscriptTitle":"Synthesis, Structure, and Properties of a Polymer Complex of Copper(II) With Maleic Acid","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-25 07:11:07","doi":"10.21203/rs.3.rs-7140677/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-07-19T11:04:02+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-07-19T10:59:44+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-07-19T05:10:38+00:00","index":"","fulltext":""},{"type":"submitted","content":"Transition Metal Chemistry","date":"2025-07-16T13:40:56+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"transition-metal-chemistry","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"tmch","sideBox":"Learn more about [Transition Metal Chemistry](http://link.springer.com/journal/11243)","snPcode":"11243","submissionUrl":"https://submission.nature.com/new-submission/11243/3","title":"Transition Metal Chemistry","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"f161ff21-2f5c-47b5-8c67-db86ecea2394","owner":[],"postedDate":"July 25th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-12-08T16:01:56+00:00","versionOfRecord":{"articleIdentity":"rs-7140677","link":"https://doi.org/10.1007/s11243-025-00705-y","journal":{"identity":"transition-metal-chemistry","isVorOnly":false,"title":"Transition Metal Chemistry"},"publishedOn":"2025-12-04 15:57:47","publishedOnDateReadable":"December 4th, 2025"},"versionCreatedAt":"2025-07-25 07:11:07","video":"","vorDoi":"10.1007/s11243-025-00705-y","vorDoiUrl":"https://doi.org/10.1007/s11243-025-00705-y","workflowStages":[]},"version":"v1","identity":"rs-7140677","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7140677","identity":"rs-7140677","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}