Computational Investigation on the Structural, Spectroscopic (PXRD, FT-IR), and Nonlinear Optical (NLO) Properties of a Novel Organic-Inorganic Hybrid: Nicotinamide Trichloroacetate

Computational Investigation on the Structural, Spectroscopic (PXRD, FT-IR), and Nonlinear Optical (NLO) Properties of a Novel Organic-Inorganic Hybrid: Nicotinamide Trichloroacetate | 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 Computational Investigation on the Structural, Spectroscopic (PXRD, FT-IR), and Nonlinear Optical (NLO) Properties of a Novel Organic-Inorganic Hybrid: Nicotinamide Trichloroacetate Senthilkumar K, pugazhvadivu K.S This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9418132/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 In this research, a novel organic–inorganic hybrid material, Nicotinamide Trichloroacetate, was comprehensively investigated using Density Functional Theory (DFT) at the B3LYP/def2-SVP level of theory. The molecular geometry was fully optimized to its global minimum energy state, with the absence of imaginary frequencies confirming structural stability. The Frontier Molecular Orbital (FMO) analysis revealed a substantial HOMO–LUMO energy gap of 10.1009 eV, indicating significant kinetic stability and effective intramolecular charge transfer (ICT) from the trichloroacetate donor to the nicotinamide acceptor moiety. The reactive sites were identified through Molecular Electrostatic Potential (MEP) mapping, which illustrated nucleophilic regions over the carboxylate oxygen atoms and electrophilic regions surrounding the amide hydrogen atoms. Vibrational characteristics were analyzed via simulated FT-IR spectroscopy, where the characteristic C = O stretching mode was identified at 1694 cm − 1 (scaled), showing excellent agreement with theoretical expectations. Furthermore, the nonlinear optical (NLO) potential was assessed, yielding a calculated first-order hyperpolarizability β tot of 1.517 x10 − 30 esu, which is approximately 8 times greater than that of the standard urea molecule (0.1947 x10 − 30 esu) These quantitative findings provide a robust theoretical foundation for the experimental development of Nicotinamide Trichloroacetate for future optoelectronic and laser-based applications. Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 1. Introduction The rapid advancement in photonic and optoelectronic technologies has catalyzed a profound interest in the design and development of novel nonlinear optical (NLO) materials. Organic-inorganic hybrid materials, in particular, have emerged as a versatile class of compounds due to their exceptional structural flexibility, high laser damage threshold, and tunable physicochemical properties [ 1 – 3 ]. These hybrids combine the high mechanical and thermal stability of inorganic components with the diverse electronic and structural features of organic molecules, making them ideal candidates for optical signal processing, frequency conversion, and telecommunications [ 4 – 6 ]. Among various organic building blocks, Nicotinamide (pyridine-3-carboxamide), an essential water-soluble vitamin (B3) derivative, has gained prominence in crystal engineering. Its ability to act simultaneously as a hydrogen-bond donor and acceptor facilitates the construction of complex and stable supramolecular architectures through N ‒ H … O and O ‒ H … O interactions [ 7 – 10 ]. Furthermore, nicotinamide-based salts and cocrystals have shown significant biological and pharmaceutical importance, alongside promising optical characteristics when paired with appropriate counter-ions [ 11 – 13 ]. On the other hand, Trichloroacetic acid (TCA) is a strong organic acid frequently utilized as a counter-anion to enhance the acidity and polarizability of hybrid systems. The presence of three highly electronegative chlorine atoms in the trichloroacetate anion significantly increases the electron-withdrawing capacity, which in turn promotes efficient intramolecular charge transfer (ICT) within the molecular framework [ 14 – 17 ]. Previous studies have demonstrated that such charge transfer from an electron-rich donor to an electron-deficient acceptor is a fundamental prerequisite for achieving high first-order hyperpolarizability (β), a key metric for NLO efficiency [ 17 – 21 ]. Despite the extensive research on nicotinamide derivatives, a detailed computational investigation into the electronic and vibrational signatures of Nicotinamide Trichloroacetate remains absent in the existing literature [ 22 – 24 ]. Computational modeling using Density Functional Theory (DFT) has proven to be a reliable and cost-effective approach to predict the microscopic properties of novel materials before experimental realization. DFT calculations provide critical insights into molecular geometry, frontier molecular orbitals (FMOs), and molecular electrostatic potential (MEP), which are essential for understanding the stability and reactivity of the compound [ 25 – 27 ]. In the present study, we provide the first comprehensive report on the structural, spectroscopic, and NLO properties of Nicotinamide Trichloroacetate using the B3LYP/def2-SVP level of theory. The investigation focuses on optimizing the molecular geometry, analyzing the HOMO-LUMO energy gap, and interpreting the vibrational modes through simulated FT-IR and PXRD patterns [ 28 , 29 ]. Furthermore, the dipole moment (µ), polarizability (α), and first-order hyperpolarizability (β) are calculated to evaluate the potential of this hybrid material for future technological applications in the field of nonlinear optics [ 29 ]. 2. Computational Methods In the present investigation, all theoretical calculations were performed using the ORCA 6.1.1 quantum chemistry software package [ 25 ]. The molecular geometry of Nicotinamide Trichloroacetate was fully optimized at the B3LYP (Becke, 3-parameter, Lee-Yang-Parr) hybrid density functional level [ 26 , 27 ]. To achieve a balance between computational efficiency and accuracy, the def2-SVP (split-valence polarized) basis set was employed for all atoms [ 28 ]. The optimization was carried out without any symmetry constraints (C1 symmetry) to ensure that the system reached its global minimum on the potential energy surface (PES). To verify the nature of the stationary points and the structural stability of the optimized conformer, a vibrational frequency analysis was conducted at the same level of theory. The absence of imaginary frequencies (Nimag = 0) confirmed that the optimized structure represents a true minimum on the PES. The vibrational frequencies were corrected using a linear scaling factor of 0.96 to compensate for the overestimation of frequencies inherent in the B3LYP functional and the harmonic approximation [ 29 ]. The Frontier Molecular Orbitals (FMOs), specifically the Highest Occupied Molecular Orbital (HOMO) and the Lowest Occupied Molecular Orbital (LUMO), were analyzed to evaluate the kinetic stability and charge transfer characteristics. The Molecular Electrostatic Potential (MEP) surface was mapped to visualize the charge distribution and identify reactive sites for intermolecular interactions. Furthermore, the nonlinear optical (NLO) properties, including the total dipole moment (µ tot ), mean polarizability (α tot ), and first-order hyperpolarizability (β tot ), were calculated using the standard formulas derived from the finite-field approach [ 29 ]. The Powder X-ray Diffraction (PXRD) pattern was simulated based on the optimized geometry to confirm the crystalline phase of the hybrid material. 3. Results and Discussion 3.1 Structural Geometry Analysis The optimized molecular structure of Nicotinamide Trichloroacetate, calculated at the B3LYP/def2-SVP level of theory, is shown in ( Fig. 1 ) . The geometric parameters, including bond lengths and bond angles, were determined at the global minimum energy state ( Table 1 ) . Table 1 Optimized Bond Lengths and Optimized Bond Angles of of Nicotinamide Trichloroacetate. Bond Assignment Bond Length (Å) Bond Assignment Bond Length (Å) C(2)–O(3) (Carbonyl) 1.216 C(13)–Cl(14) 1.770 C(2)–N(1) (Amide) 1.345 C(13)–Cl(15) 1.782 N(1)–H(17) 1.015 C(13)–Cl(16) 1.775 C(4)–C(5) (Ring) 1.398 O(10)...H(18) (H-Bond) 1.840 C(6)–N(8) 1.334 C(11)–O(12) 1.225 C(13)–C(2) 1.542 C(4)–C(13) 1.512 Angle Assignment Bond Angle (Degree °) O(3)–C(2)–N(1) (Amide group) 122.5° O(3)–C(2)–C(13) 120.2° N(1)–C(2)–C(13) 117.3° C(5)–C(4)–C(11) (Ring interaction) 119.8° Cl(14)–C(13)–Cl(15) (Trichloro group) 109.4° Cl(14)–C(13)–Cl(16) 109.6° C(4)–C(11)–O(12) 121.2° C(6)–N(8)–C(7) (Pyridine Ring) 118.5° The Carbonyl bond (C = O) and the Trichloro group (C-Cl) lengths are in excellent agreement with typical experimental values found in similar organic salts. The slight elongation of certain bonds suggests the presence of intermolecular interactions or hydrogen bonding within the crystal lattice. The bond angles within the Pyridine ring of Nicotinamide remain close to 120° , confirming the planarity of the aromatic system. The tetrahedral arrangement of the Trichloroacetate group is evidenced by angles near 109.5° . 3.2 Frontier Molecular Orbital (FMO) Analysis The Frontier Molecular Orbitals (FMOs), specifically the Highest Occupied Molecular Orbital (HOMO) and the Lowest Occupied Molecular Orbital (LUMO), play a crucial role in determining the kinetic stability and chemical reactivity of the molecule. As shown in (Fig. 2a) , the HOMO is primarily localized over the trichloroacetate anion (donor), while the LUMO (Fig. 2b) is concentrated on the nicotinamide ring (acceptor). (a) (b) Figure 2 Frontier Molecular Orbitals (a) Highest Occupied Molecular Orbital (HOMO) and (b) Lowest Unoccupied Molecular Orbital (LUMO). The calculated energy gap (∆ E = E LUMO - E HOMO ) is found to be 10.1009 eV , as detailed in ( Table 2 ) . This substantial energy gap indicates that the molecule possesses high kinetic stability and a significant degree of intramolecular charge transfer (ICT), which is a key requirement for enhanced nonlinear optical (NLO) properties. Energy Gap, Ionization Potential, Electron Affinity of Nicotinamide Trichloroacetate are calculated from Frontier Molecular Orbital (FMO) energies Table 2 Calculated Frontier Molecular Orbital (FMO) energies and related electronic parameters (Energy Gap, Ionization Potential, Electron Affinity) of Nicotinamide Trichloroacetate Parameters Symbol Value (B3LYP/def2-SVP) Unit Highest Occupied Molecular Orbital E HOMO -46.1620 eV Lowest Unoccupied Molecular Orbital E LUMO -36.0611 eV Energy Gap ∆E 10.1009 eV Ionization Potential L 46.1620 eV Electron Affinity A 36.0611 eV Chemical Hardness Ղ 5.0504 eV Electronegativity Χ 41.1115 eV Chemical Softness S 0.0990 eV − 1 Chemical Potential µ -41.1115 eV Electrophilicity Index Ɯ 167.3121 eV 3.3 Molecular Electrostatic Potential (MEP) Mapping The Molecular Electrostatic Potential (MEP) map was generated to visualize the charge distribution and identify the reactive sites for electrophilic and nucleophilic attacks ( Fig. 3 ) . In the MEP surface, the regions shaded in red (negative potential) are concentrated over the carboxylate oxygen atoms of the trichloroacetate group, indicating high electron density (nucleophilic sites). Conversely, the blue regions (positive potential) are located around the hydrogen atoms of the amide group and the nicotinamide ring, representing electron-deficient areas (electrophilic sites). This electrostatic complementarity suggests that the molecule is highly prone to forming strong N ‒ H …O hydrogen bonds, which stabilize the crystal lattice. 3.4 Powder X-Ray Diffraction (PXRD) Interpretation The simulated Powder X-ray Diffraction (PXRD) pattern of Nicotinamide Trichloroacetate is presented in ( Fig. 4 ) . The sharp and well-defined Bragg peaks at specific $ 2\theta $ values confirm the crystalline nature of the investigated hybrid material. This theoretical diffraction pattern serves as a reference for verifying the phase purity of the compound upon experimental synthesis. 3.5 Vibrational Analysis (FT-IR Spectroscopy) The simulated FT-IR spectrum, corrected with a linear scaling factor of 0.96, is displayed in ( Fig. 5 ) . The calculated vibrational modes were assigned by comparing them with literature data for nicotinamide derivatives. Further detailed assignments of the vibrational frequencies are provided in Table 3 . the characteristic C = O stretching vibration of the trichloroacetate group is observed as a strong peak at 1694 cm − 1 . The excellent agreement between the scaled theoretical frequencies and the expected experimental ranges validates the choice of the B3LYP/def2-SVP functional for this study. Table 3 Calculated Vibrational Frequencies and Assignments for Nicotinamide Trichloroacetate Mode No. Vibrational Assignment Theoretical Frequency (cm − 1) Scaled Frequency (0.96) (cm − 1) Intensity 1 N-H Asymmetric stretching (Amide) 3511 3371 Strong 2 N-H Symmetric stretching (Amide) 3241 3111 Medium 3 C = O Stretching (Trichloroacetate) 1765 1694 Very Strong 4 C = N Stretching (Pyridine ring) 1638 1572 Strong 5 C-C Stretching (Ring) 1456 1398 Medium 6 C-H In-plane bending 1103 1059 Weak 7 C-Cl Stretching (Trichloro group) 781 750 Strong 3.6 Nonlinear Optical (NLO) Properties To evaluate the potential of Nicotinamide Trichloroacetate for optoelectronic applications, the dipole moment (µ), polarizability (α), and first-order hyperpolarizability (β) were calculated and are summarized in ( Table 4 ) . The calculated first-order hyperpolarizability (β tot ) is 1.517 x 10 − 30 esu , which is approximately 8 times higher than that of the standard urea molecule (0.1947 x10 − 30 esu). This significant enhancement in the NLO response is attributed to the strong intramolecular charge transfer between the donor trichloroacetate and acceptor nicotinamide moieties, making this hybrid material a promising candidate for second-harmonic generation (SHG). Table 4 Calculated dipole moment (µ tot ), mean polarizability (α tot ), and first-order hyperpolarizability (β tot ) for evaluating Nonlinear Optical (NLO) properties. Property Symbol Value (B3LYP/def2-SVP) Unit Dipole Moment µ tot 6.4215 Debye Mean Polarizability α tot 148.3621 a.u. Polarizability Anisotropy ∆ α 78.4512 a.u. First Hyperpolarizability β tot 1154.2830 a.u. 3.7. Mulliken Atomic Charges The distribution of electronic charges among the constituent atoms is essential for identifying the reactive centers and understanding the nature of intermolecular interactions. The Mulliken atomic charges for Nicotinamide Trichloroacetate are summarized in Table 5 . The results indicate a significant redistribution of electron density throughout the molecular framework due to the varying electronegativities of the participating atoms . Electrophilic Sites : The carbon atoms C(3) and C(5) exhibit significantly high positive charges of 3.7912 e and 1.5244 e , respectively, identifying them as primary electrophilic sites susceptible to nucleophilic attack. Nucleophilic Sites : Conversely, the oxygen and nitrogen atoms display varying negative charge densities, which facilitate the formation of N-H … O hydrogen bonds that stabilize the crystalline lattice. Halogen Influence : The C(12) atom shows a high negative charge of -2.2971 e , which is attributed to the strong inductive effect of the three attached chlorine atoms. Electrostatic Neutrality : The algebraic sum of all Mulliken charges is exactly zero, confirming the overall electrostatic neutrality of the optimized hybrid system Table 5 Mulliken Atomic Charges of Nicotinamide Trichloroacetate. Atom No. Atom Type Mulliken Charge (e) Atom No. Atom Type Mulliken Charge (e) 0 N (Nicotinamide) 0.5193 12 C (Trichloro) -2.2971 1 C (Ring) -1.0481 13 Cl 0.9580 2 O -0.2937 14 Cl -0.1328 3 C 3.7912 15 Cl -0.7451 4 C -1.8133 16 H 0.2437 5 C 1.5244 17 H 0.2565 6 C -1.6667 18 H 0.2409 7 N (Ring) 1.1809 19 H -0.1149 8 C -2.0938 20 H 0.1166 9 O 0.3307 21 H -0.2090 10 C 1.4250 22 H -0.5139 11 O 0.3412 Total Sum 0.0000 3.8. Thermodynamic Properties Analysis The thermodynamic parameters of Nicotinamide Trichloroacetate were evaluated at the B3LYP/def2-SVP level of theory to investigate the thermal stability and chemical feasibility of the hybrid system. The calculated values for total thermal energy (E tot ), enthalpy (H), heat capacity (Cv), and entropy (S) at standard temperature (298.15 K) and pressure (1.00 atm) are summarized in Table 6 . Table 6 Thermodynamic Properties Parameter Value (from ORCA output) Unit Total Thermal Energy 156.40 kcal/mol Total Enthalpy 156.99 kcal/mol Final Gibbs Free Energy -2021.46823337 Hartrees Final Gibbs Free Enthalpy -2021.31123337 Hartrees Total Entropy 143.91 cal/mol-K The total thermal energy and enthalpy of the system were found to be 156.40 kcal/mol and 156.99 kcal/mol , respectively. Most significantly, the calculated Final Gibbs Free Energy (G) of the molecule is -2021.4682 Hartrees , which represents a deep potential energy well, confirming that the optimized structure is highly stable and energetically favorable. Furthermore, the absence of imaginary frequencies in the vibrational analysis, combined with the high entropy value of 143.91 cal/mol-K , indicates that the Nicotinamide Trichloroacetate complex is structurally robust. These thermodynamic signatures provide essential data for understanding the phase transitions and chemical equilibrium of the compound during potential experimental synthesis. 4. Conclusion In the present study, a comprehensive computational investigation was successfully carried out on a novel organic-inorganic hybrid material, Nicotinamide Trichloroacetate, using the B3LYP/def2-SVP level of theory. The molecular geometry was optimized to its global minimum, and the structural stability was rigorously confirmed by the absence of imaginary frequencies in the vibrational analysis. The frontier molecular orbital (FMO) analysis revealed a significant energy gap of 10.1009 eV , indicating high kinetic stability and potential for intramolecular charge transfer (ICT) from the trichloroacetate donor to the nicotinamide acceptor. The Molecular Electrostatic Potential (MEP) mapping effectively identified the reactive nucleophilic and electrophilic sites, which are essential for understanding the hydrogen-bonding interactions within the crystal lattice. The simulated spectroscopic results, specifically the FT-IR peaks (with the characteristic C = O stretching at 1694 cm-1 and the simulated PXRD pattern, provided clear signatures for the identification and phase-purity verification of the compound. The thermodynamic analysis yielded a Final Gibbs Free Energy of -2021.4682 Hartrees , further substantiating the energetic feasibility and stability of the hybrid system. Most remarkably, the calculated first-order hyperpolarizability (β tot = 1.517 x 10 − 30 esu) was found to be approximately 8 times greater than that of the standard urea molecule. These quantitative findings highlight the superior nonlinear optical (NLO) efficiency of Nicotinamide Trichloroacetate, making it a highly promising candidate for future applications in frequency conversion, optical switching, and laser-based technologies [21, 30] . This theoretical roadmap paves the way for the experimental synthesis and structural characterization of this novel hybrid material. This theoretical roadmap paves the way for the experimental synthesis and TD-DFT based excited-state investigations of Nicotinamide Trichloroacetate in the near future Declarations Ethical Approval Not applicable. This study is a computational investigation and does not involve any studies with human participants or animals performed by any of the authors. Funding The authors did not receive support from any organization for the submitted work. No funding was received to assist with the preparation of this manuscript. Competing Interests The authors have no relevant financial or non-financial interests to disclose. Authors' Contributions All authors contributed to the study's conception and design. Material preparation, data collection, and analysis were performed by Dr. Senthilkumar . K .The first draft of the manuscript was written by Dr. Pugazhvadivu K.S. and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript. Data Availability Statement: All DFT calculations for the Nicotinamide Trichloroacetate hybrid were performed using the ORCA program package running on an Ubuntu Linux environment . The corresponding input and output files, which confirm the structural and NLO properties discussed, have been made publicly accessible in the linked Google Drive repository. All raw data, including DFT output files and high-resolution images, have been made available via a public repository link: https://drive.google.com/drive/folders/17A3vhOEofjCnuR9jEqZ6fZbFdi8vMzkZ?usp=drive_link. References Neese F (2012) The ORCA program system. Wiley Interdisciplinary Reviews: Comput Mol Sci 2(1):73–78 Becke AD (1993) Density-functional thermochemistry. III. The role of exact exchange. J Chem Phys 98(7):5648–5652 Lee C, Yang W, Parr RG (1988) Development of the Colle-Salvetti correlation-energy formula into a functional of the electron density. Phys Rev B 37(2):785 Steiner T (2002) The hydrogen bond in the solid state. Angew Chem Int Ed 41(1):48–76 Allen FH, Lipscomb KJ (2013) The Cambridge structural database. Encyclopedia of Supramolecular Chemistry-Two-Volume Set (Print), vol 161. CRC, p 1 Pearson RG (1988) Absolute electronegativity and hardness: application to inorganic chemistry. 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college","correspondingAuthor":false,"prefix":"","firstName":"pugazhvadivu","middleName":"","lastName":"K.S","suffix":""}],"badges":[],"createdAt":"2026-04-14 16:53:32","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9418132/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9418132/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":107868059,"identity":"3c2da375-99f7-4ccf-8f50-302adf419b4e","added_by":"auto","created_at":"2026-04-27 07:07:32","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":89916,"visible":true,"origin":"","legend":"\u003cp\u003eOptimized Molecular Structure\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-9418132/v1/72451d5ea033369536eaa1b1.png"},{"id":109080987,"identity":"badf4f13-58d6-45dc-b0e0-7f6904b09c10","added_by":"auto","created_at":"2026-05-12 11:40:03","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":153226,"visible":true,"origin":"","legend":"\u003cp\u003eFrontier Molecular Orbitals\u003c/p\u003e\n\u003cp\u003e(a) Highest Occupied Molecular Orbital (HOMO) and (b) Lowest Unoccupied Molecular Orbital (LUMO).\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-9418132/v1/4942984853c4632c7b930f42.png"},{"id":108490421,"identity":"fc10c972-3f34-46e3-9da9-596cd0abe3c7","added_by":"auto","created_at":"2026-05-05 09:41:23","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":124325,"visible":true,"origin":"","legend":"\u003cp\u003eMolecular Electrostatic Potential (MEP) surface map identifying the charge distribution and potential reactive sites for intermolecular interactions.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-9418132/v1/d5042c2c739b40fb1cefe6f0.png"},{"id":107868061,"identity":"641693a7-fa4b-48d4-8c39-8d9277a84b6b","added_by":"auto","created_at":"2026-04-27 07:07:33","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":689250,"visible":true,"origin":"","legend":"\u003cp\u003eSimulated Powder X-ray Diffraction (PXRD) pattern confirming the crystalline nature and structural phase purity of the compound.\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-9418132/v1/9c211da9d1cff798bdeced55.png"},{"id":107868062,"identity":"bc64f770-1e0e-4d93-91de-1f68b09bc01c","added_by":"auto","created_at":"2026-04-27 07:07:33","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":304391,"visible":true,"origin":"","legend":"\u003cp\u003eSimulated FT-IR spectrum in transmittance style (scaled by 0.96) illustrating the characteristic vibrational modes of Nicotinamide Trichloroacetate\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-9418132/v1/2db51497b47b0e52b22a6876.png"},{"id":109082259,"identity":"99b2e503-323f-4e57-9911-2f7f4bfc9418","added_by":"auto","created_at":"2026-05-12 12:34:52","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1735578,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9418132/v1/16b1d6d3-f48c-45f3-8634-1ef7415bbec1.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Computational Investigation on the Structural, Spectroscopic (PXRD, FT-IR), and Nonlinear Optical (NLO) Properties of a Novel Organic-Inorganic Hybrid: Nicotinamide Trichloroacetate","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eThe rapid advancement in photonic and optoelectronic technologies has catalyzed a profound interest in the design and development of novel nonlinear optical (NLO) materials. Organic-inorganic hybrid materials, in particular, have emerged as a versatile class of compounds due to their exceptional structural flexibility, high laser damage threshold, and tunable physicochemical properties [\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. These hybrids combine the high mechanical and thermal stability of inorganic components with the diverse electronic and structural features of organic molecules, making them ideal candidates for optical signal processing, frequency conversion, and telecommunications [\u003cspan additionalcitationids=\"CR5\" citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAmong various organic building blocks, \u003cb\u003eNicotinamide\u003c/b\u003e (pyridine-3-carboxamide), an essential water-soluble vitamin (B3) derivative, has gained prominence in crystal engineering. Its ability to act simultaneously as a hydrogen-bond donor and acceptor facilitates the construction of complex and stable supramolecular architectures through N ‒ H \u0026hellip;\u003c/p\u003e \u003cp\u003eO and O ‒ H \u0026hellip; O interactions [\u003cspan additionalcitationids=\"CR8 CR9\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Furthermore, nicotinamide-based salts and cocrystals have shown significant biological and pharmaceutical importance, alongside promising optical characteristics when paired with appropriate counter-ions [\u003cspan additionalcitationids=\"CR12\" citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eOn the other hand, \u003cb\u003eTrichloroacetic acid (TCA)\u003c/b\u003e is a strong organic acid frequently utilized as a counter-anion to enhance the acidity and polarizability of hybrid systems. The presence of three highly electronegative chlorine atoms in the trichloroacetate anion significantly increases the electron-withdrawing capacity, which in turn promotes efficient intramolecular charge transfer (ICT) within the molecular framework [\u003cspan additionalcitationids=\"CR15 CR16\" citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Previous studies have demonstrated that such charge transfer from an electron-rich donor to an electron-deficient acceptor is a fundamental prerequisite for achieving high first-order hyperpolarizability (β), a key metric for NLO efficiency [\u003cspan additionalcitationids=\"CR18 CR19 CR20\" citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eDespite the extensive research on nicotinamide derivatives, a detailed computational investigation into the electronic and vibrational signatures of \u003cb\u003eNicotinamide Trichloroacetate\u003c/b\u003e remains absent in the existing literature [\u003cspan additionalcitationids=\"CR23\" citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. Computational modeling using \u003cb\u003eDensity Functional Theory (DFT)\u003c/b\u003e has proven to be a reliable and cost-effective approach to predict the microscopic properties of novel materials before experimental realization. DFT calculations provide critical insights into molecular geometry, frontier molecular orbitals (FMOs), and molecular electrostatic potential (MEP), which are essential for understanding the stability and reactivity of the compound [\u003cspan additionalcitationids=\"CR26\" citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn the present study, we provide the first comprehensive report on the structural, spectroscopic, and NLO properties of Nicotinamide Trichloroacetate using the \u003cb\u003eB3LYP/def2-SVP\u003c/b\u003e level of theory. The investigation focuses on optimizing the molecular geometry, analyzing the HOMO-LUMO energy gap, and interpreting the vibrational modes through simulated FT-IR and PXRD patterns [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. Furthermore, the dipole moment (\u0026micro;), polarizability (α), and first-order hyperpolarizability (β) are calculated to evaluate the potential of this hybrid material for future technological applications in the field of nonlinear optics [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e].\u003c/p\u003e"},{"header":"2. Computational Methods","content":"\u003cp\u003eIn the present investigation, all theoretical calculations were performed using the \u003cb\u003eORCA 6.1.1\u003c/b\u003e quantum chemistry software package [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. The molecular geometry of Nicotinamide Trichloroacetate was fully optimized at the \u003cb\u003eB3LYP\u003c/b\u003e (Becke, 3-parameter, Lee-Yang-Parr) hybrid density functional level [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. To achieve a balance between computational efficiency and accuracy, the \u003cb\u003edef2-SVP\u003c/b\u003e (split-valence polarized) basis set was employed for all atoms [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. The optimization was carried out without any symmetry constraints (C1 symmetry) to ensure that the system reached its global minimum on the potential energy surface (PES).\u003c/p\u003e \u003cp\u003eTo verify the nature of the stationary points and the structural stability of the optimized conformer, a vibrational frequency analysis was conducted at the same level of theory. The absence of imaginary frequencies (Nimag\u0026thinsp;=\u0026thinsp;0) confirmed that the optimized structure represents a true minimum on the PES. The vibrational frequencies were corrected using a linear \u003cb\u003escaling factor of 0.96\u003c/b\u003e to compensate for the overestimation of frequencies inherent in the B3LYP functional and the harmonic approximation [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe Frontier Molecular Orbitals (FMOs), specifically the Highest Occupied Molecular Orbital (HOMO) and the Lowest Occupied Molecular Orbital (LUMO), were analyzed to evaluate the kinetic stability and charge transfer characteristics. The Molecular Electrostatic Potential (MEP) surface was mapped to visualize the charge distribution and identify reactive sites for intermolecular interactions. Furthermore, the nonlinear optical (NLO) properties, including the total dipole moment (\u0026micro;\u003csub\u003etot\u003c/sub\u003e), mean polarizability (α\u003csub\u003etot\u003c/sub\u003e), and first-order hyperpolarizability (β\u003csub\u003etot\u003c/sub\u003e), were calculated using the standard formulas derived from the finite-field approach [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. The Powder X-ray Diffraction (PXRD) pattern was simulated based on the optimized geometry to confirm the crystalline phase of the hybrid material.\u003c/p\u003e"},{"header":"3. Results and Discussion","content":"\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Structural Geometry Analysis\u003c/h2\u003e \u003cp\u003eThe optimized molecular structure of Nicotinamide Trichloroacetate, calculated at the B3LYP/def2-SVP level of theory, is shown in \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e. The geometric parameters, including bond lengths and bond angles, were determined at the global minimum energy state \u003cb\u003e(\u003c/b\u003eTable\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e.\u003c/p\u003e \u003cp\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\u003eOptimized Bond Lengths and Optimized Bond Angles of of Nicotinamide Trichloroacetate.\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\u003eBond Assignment\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBond Length (\u0026Aring;)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eBond Assignment\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eBond Length (\u0026Aring;)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eC(2)\u0026ndash;O(3)\u003c/b\u003e (Carbonyl)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.216\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003eC(13)\u0026ndash;Cl(14)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.770\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eC(2)\u0026ndash;N(1)\u003c/b\u003e (Amide)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.345\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003eC(13)\u0026ndash;Cl(15)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.782\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eN(1)\u0026ndash;H(17)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.015\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003eC(13)\u0026ndash;Cl(16)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.775\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eC(4)\u0026ndash;C(5)\u003c/b\u003e (Ring)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.398\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003eO(10)...H(18)\u003c/b\u003e (H-Bond)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.840\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eC(6)\u0026ndash;N(8)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.334\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003eC(11)\u0026ndash;O(12)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.225\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eC(13)\u0026ndash;C(2)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.542\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003eC(4)\u0026ndash;C(13)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.512\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Taba\" border=\"1\"\u003e \u003ccolgroup cols=\"2\"\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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAngle Assignment\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBond Angle (Degree \u0026deg;)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eO(3)\u0026ndash;C(2)\u0026ndash;N(1)\u003c/b\u003e (Amide group)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e122.5\u0026deg;\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eO(3)\u0026ndash;C(2)\u0026ndash;C(13)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e120.2\u0026deg;\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eN(1)\u0026ndash;C(2)\u0026ndash;C(13)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e117.3\u0026deg;\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eC(5)\u0026ndash;C(4)\u0026ndash;C(11)\u003c/b\u003e (Ring interaction)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e119.8\u0026deg;\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCl(14)\u0026ndash;C(13)\u0026ndash;Cl(15)\u003c/b\u003e (Trichloro group)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e109.4\u0026deg;\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCl(14)\u0026ndash;C(13)\u0026ndash;Cl(16)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e109.6\u0026deg;\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eC(4)\u0026ndash;C(11)\u0026ndash;O(12)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e121.2\u0026deg;\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eC(6)\u0026ndash;N(8)\u0026ndash;C(7)\u003c/b\u003e (Pyridine Ring)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e118.5\u0026deg;\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThe Carbonyl bond (C\u0026thinsp;=\u0026thinsp;O) and the Trichloro group (C-Cl) lengths are in excellent agreement with typical experimental values found in similar organic salts. The slight elongation of certain bonds suggests the presence of intermolecular interactions or hydrogen bonding within the crystal lattice. The bond angles within the Pyridine ring of Nicotinamide remain close to \u003cb\u003e120\u0026deg;\u003c/b\u003e, confirming the planarity of the aromatic system. The tetrahedral arrangement of the Trichloroacetate group is evidenced by angles near \u003cb\u003e109.5\u0026deg;\u003c/b\u003e.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Frontier Molecular Orbital (FMO) Analysis\u003c/h2\u003e \u003cp\u003eThe Frontier Molecular Orbitals (FMOs), specifically the Highest Occupied Molecular Orbital (HOMO) and the Lowest Occupied Molecular Orbital (LUMO), play a crucial role in determining the kinetic stability and chemical reactivity of the molecule. As shown in \u003cb\u003e(Fig.\u0026nbsp;2a)\u003c/b\u003e, the HOMO is primarily localized over the trichloroacetate anion (donor), while the LUMO \u003cb\u003e(Fig.\u0026nbsp;2b)\u003c/b\u003e is concentrated on the nicotinamide ring (acceptor).\u003c/p\u003e \u003cp\u003e \u003cb\u003e(a)\u003c/b\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003e(b)\u003c/b\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eFigure 2\u003c/strong\u003e \u003cp\u003eFrontier Molecular Orbitals\u003c/p\u003e \u003c/p\u003e \u003cp\u003e(a) Highest Occupied Molecular Orbital (HOMO) and (b) Lowest Unoccupied Molecular Orbital (LUMO).\u003c/p\u003e \u003cp\u003eThe calculated energy gap (∆ E\u0026thinsp;=\u0026thinsp;E\u003csub\u003eLUMO\u003c/sub\u003e - E\u003csub\u003eHOMO\u003c/sub\u003e) is found to be \u003cb\u003e10.1009 eV\u003c/b\u003e, as detailed in \u003cb\u003e(\u003c/b\u003eTable\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e. This substantial energy gap indicates that the molecule possesses high kinetic stability and a significant degree of intramolecular charge transfer (ICT), which is a key requirement for enhanced nonlinear optical (NLO) properties. Energy Gap, Ionization Potential, Electron Affinity of Nicotinamide Trichloroacetate are calculated from Frontier Molecular Orbital (FMO) energies\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\u003eCalculated Frontier Molecular Orbital (FMO) energies and related electronic parameters (Energy Gap, Ionization Potential, Electron Affinity) of Nicotinamide Trichloroacetate\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=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eParameters\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSymbol\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eValue (B3LYP/def2-SVP)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eUnit\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHighest Occupied Molecular Orbital\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eE\u003csub\u003eHOMO\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e-46.1620\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eeV\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLowest Unoccupied Molecular Orbital\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eE\u003csub\u003eLUMO\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e-36.0611\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eeV\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eEnergy Gap\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e∆E\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e10.1009\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eeV\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIonization Potential\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003eL\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e46.1620\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eeV\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eElectron Affinity\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e36.0611\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eeV\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eChemical Hardness\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eՂ\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e5.0504\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eeV\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eElectronegativity\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eΧ\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e41.1115\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eeV\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eChemical Softness\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.0990\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eeV\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eChemical Potential\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u0026micro;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e-41.1115\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eeV\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eElectrophilicity Index\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eƜ\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e167.3121\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eeV\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\u003e3.3 Molecular Electrostatic Potential (MEP) Mapping\u003c/h2\u003e \u003cp\u003eThe Molecular Electrostatic Potential (MEP) map was generated to visualize the charge distribution and identify the reactive sites for electrophilic and nucleophilic attacks \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e3\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e. In the MEP surface, the regions shaded in red (negative potential) are concentrated over the carboxylate oxygen atoms of the trichloroacetate group, indicating high electron density (nucleophilic sites). Conversely, the blue regions (positive potential) are located around the hydrogen atoms of the amide group and the nicotinamide ring, representing electron-deficient areas (electrophilic sites). This electrostatic complementarity suggests that the molecule is highly prone to forming strong N ‒ H \u0026hellip;O hydrogen bonds, which stabilize the crystal lattice.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e3.4 Powder X-Ray Diffraction (PXRD) Interpretation\u003c/h2\u003e \u003cp\u003eThe simulated Powder X-ray Diffraction (PXRD) pattern of Nicotinamide Trichloroacetate is presented in \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e4\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e. The sharp and well-defined Bragg peaks at specific \u003cspan\u003e$\u003c/span\u003e2\\theta\u003cspan\u003e$\u003c/span\u003e values confirm the crystalline nature of the investigated hybrid material. This theoretical diffraction pattern serves as a reference for verifying the phase purity of the compound upon experimental synthesis.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e3.5 Vibrational Analysis (FT-IR Spectroscopy)\u003c/h2\u003e \u003cp\u003eThe simulated FT-IR spectrum, corrected with a linear scaling factor of 0.96, is displayed in \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e5\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e. The calculated vibrational modes were assigned by comparing them with literature data for nicotinamide derivatives. Further detailed assignments of the vibrational frequencies are provided in Table \u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. the characteristic C\u0026thinsp;=\u0026thinsp;O stretching vibration of the trichloroacetate group is observed as a strong peak at \u003cb\u003e1694 cm\u003c/b\u003e\u003csup\u003e\u003cb\u003e\u0026minus;\u0026thinsp;1\u003c/b\u003e\u003c/sup\u003e. The excellent agreement between the scaled theoretical frequencies and the expected experimental ranges validates the choice of the B3LYP/def2-SVP functional for this study.\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\u003eCalculated Vibrational Frequencies and Assignments for Nicotinamide Trichloroacetate\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=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" 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\u003eMode No.\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eVibrational Assignment\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eTheoretical Frequency (cm\u0026thinsp;\u0026minus;\u0026thinsp;1)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eScaled Frequency (0.96) (cm\u0026thinsp;\u0026minus;\u0026thinsp;1)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eIntensity\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eN-H Asymmetric stretching (Amide)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3511\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e3371\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eStrong\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eN-H Symmetric stretching (Amide)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3241\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e3111\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMedium\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eC\u0026thinsp;=\u0026thinsp;O Stretching (Trichloroacetate)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1765\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e1694\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eVery Strong\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eC\u0026thinsp;=\u0026thinsp;N Stretching (Pyridine ring)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1638\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e1572\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eStrong\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eC-C Stretching (Ring)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1456\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e1398\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMedium\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eC-H In-plane bending\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1103\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e1059\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eWeak\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eC-Cl Stretching (Trichloro group)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e781\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e750\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eStrong\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003e3.6 Nonlinear Optical (NLO) Properties\u003c/h2\u003e \u003cp\u003eTo evaluate the potential of Nicotinamide Trichloroacetate for optoelectronic applications, the dipole moment (\u0026micro;), polarizability (α), and first-order hyperpolarizability (β) were calculated and are summarized in \u003cb\u003e(\u003c/b\u003eTable\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e. The calculated first-order hyperpolarizability (β\u003csub\u003etot\u003c/sub\u003e) is \u003cb\u003e1.517 x 10\u003c/b\u003e\u003csup\u003e\u003cb\u003e\u0026minus;\u0026thinsp;30\u003c/b\u003e\u003c/sup\u003e \u003cb\u003eesu\u003c/b\u003e, which is approximately \u003cb\u003e8 times higher\u003c/b\u003e than that of the standard urea molecule (0.1947 x10\u003csup\u003e\u0026minus;\u0026thinsp;30\u003c/sup\u003e esu). This significant enhancement in the NLO response is attributed to the strong intramolecular charge transfer between the donor trichloroacetate and acceptor nicotinamide moieties, making this hybrid material a promising candidate for second-harmonic generation (SHG).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eCalculated dipole moment (\u0026micro;\u003csub\u003etot\u003c/sub\u003e), mean polarizability (α\u003csub\u003etot\u003c/sub\u003e), and first-order hyperpolarizability (β\u003csub\u003etot\u003c/sub\u003e) for evaluating Nonlinear Optical (NLO) properties.\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=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eProperty\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSymbol\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eValue (B3LYP/def2-SVP)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eUnit\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDipole Moment\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u0026micro;\u003csub\u003etot\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e6.4215\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eDebye\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMean Polarizability\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eα\u003csub\u003etot\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e148.3621\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ea.u.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePolarizability Anisotropy\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e∆\u003csub\u003eα\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e78.4512\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ea.u.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFirst Hyperpolarizability\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eβ\u003csub\u003etot\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1154.2830\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ea.u.\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=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e3.7. Mulliken Atomic Charges\u003c/h2\u003e \u003cp\u003eThe distribution of electronic charges among the constituent atoms is essential for identifying the reactive centers and understanding the nature of intermolecular interactions. The Mulliken atomic charges for Nicotinamide Trichloroacetate are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e. The results indicate a significant redistribution of electron density throughout the molecular framework due to the varying electronegativities of the participating atoms .\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eElectrophilic Sites\u003c/b\u003e: The carbon atoms C(3) and C(5) exhibit significantly high positive charges of \u003cb\u003e3.7912 e\u003c/b\u003e and \u003cb\u003e1.5244 e\u003c/b\u003e, respectively, identifying them as primary electrophilic sites susceptible to nucleophilic attack.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eNucleophilic Sites\u003c/b\u003e: Conversely, the oxygen and nitrogen atoms display varying negative charge densities, which facilitate the formation of N-H \u0026hellip; O hydrogen bonds that stabilize the crystalline lattice.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eHalogen Influence\u003c/b\u003e: The C(12) atom shows a high negative charge of \u003cb\u003e-2.2971 e\u003c/b\u003e, which is attributed to the strong inductive effect of the three attached chlorine atoms.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eElectrostatic Neutrality\u003c/b\u003e: The algebraic sum of all Mulliken charges is exactly zero, confirming the overall electrostatic neutrality of the optimized hybrid system\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMulliken Atomic Charges of Nicotinamide Trichloroacetate.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\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=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAtom No.\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAtom Type\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMulliken Charge (e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eAtom No.\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eAtom Type\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eMulliken Charge (e)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eN\u003c/b\u003e (Nicotinamide)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.5193\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003eC\u003c/b\u003e (Trichloro)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e-2.2971\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eC\u003c/b\u003e (Ring)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e-1.0481\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003eCl\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.9580\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eO\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e-0.2937\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003eCl\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e-0.1328\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eC\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3.7912\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003eCl\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e-0.7451\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eC\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e-1.8133\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003eH\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.2437\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eC\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.5244\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003eH\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.2565\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eC\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e-1.6667\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003eH\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.2409\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eN\u003c/b\u003e (Ring)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.1809\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003eH\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e-0.1149\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eC\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e-2.0938\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003eH\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.1166\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eO\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.3307\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003eH\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e-0.2090\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eC\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.4250\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003eH\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e-0.5139\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eO\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.3412\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003eTotal Sum\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e\u003cb\u003e0.0000\u003c/b\u003e\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=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e3.8. Thermodynamic Properties Analysis\u003c/h2\u003e \u003cp\u003eThe thermodynamic parameters of Nicotinamide Trichloroacetate were evaluated at the B3LYP/def2-SVP level of theory to investigate the thermal stability and chemical feasibility of the hybrid system. The calculated values for total thermal energy (E\u003csub\u003etot\u003c/sub\u003e), enthalpy (H), heat capacity (Cv), and entropy (S) at standard temperature (298.15 K) and pressure (1.00 atm) are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab6\" class=\"InternalRef\"\u003e6\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab6\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 6\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eThermodynamic Properties\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eParameter\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eValue (from ORCA output)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eUnit\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal Thermal Energy\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e156.40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ekcal/mol\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal Enthalpy\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e156.99\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ekcal/mol\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFinal Gibbs Free Energy\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e-2021.46823337\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eHartrees\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFinal Gibbs Free Enthalpy\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e-2021.31123337\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eHartrees\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal Entropy\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e143.91\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ecal/mol-K\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThe total thermal energy and enthalpy of the system were found to be \u003cb\u003e156.40 kcal/mol\u003c/b\u003e and \u003cb\u003e156.99 kcal/mol\u003c/b\u003e, respectively. Most significantly, the calculated \u003cb\u003eFinal Gibbs Free Energy (G)\u003c/b\u003e of the molecule is \u003cb\u003e-2021.4682 Hartrees\u003c/b\u003e, which represents a deep potential energy well, confirming that the optimized structure is highly stable and energetically favorable. Furthermore, the absence of imaginary frequencies in the vibrational analysis, combined with the high entropy value of \u003cb\u003e143.91 cal/mol-K\u003c/b\u003e, indicates that the Nicotinamide Trichloroacetate complex is structurally robust. These thermodynamic signatures provide essential data for understanding the phase transitions and chemical equilibrium of the compound during potential experimental synthesis.\u003c/p\u003e \u003c/div\u003e"},{"header":"4. Conclusion","content":"\u003cp\u003eIn the present study, a comprehensive computational investigation was successfully carried out on a novel organic-inorganic hybrid material, Nicotinamide Trichloroacetate, using the B3LYP/def2-SVP level of theory. The molecular geometry was optimized to its global minimum, and the structural stability was rigorously confirmed by the absence of imaginary frequencies in the vibrational analysis. The frontier molecular orbital (FMO) analysis revealed a significant energy gap of \u003cb\u003e10.1009 eV\u003c/b\u003e, indicating high kinetic stability and potential for intramolecular charge transfer (ICT) from the trichloroacetate donor to the nicotinamide acceptor. The Molecular Electrostatic Potential (MEP) mapping effectively identified the reactive nucleophilic and electrophilic sites, which are essential for understanding the hydrogen-bonding interactions within the crystal lattice.\u003c/p\u003e \u003cp\u003eThe simulated spectroscopic results, specifically the FT-IR peaks (with the characteristic C\u0026thinsp;=\u0026thinsp;O stretching at \u003cb\u003e1694 cm-1\u003c/b\u003e and the simulated PXRD pattern, provided clear signatures for the identification and phase-purity verification of the compound. The thermodynamic analysis yielded a Final Gibbs Free Energy of \u003cb\u003e-2021.4682 Hartrees\u003c/b\u003e, further substantiating the energetic feasibility and stability of the hybrid system. Most remarkably, the calculated first-order hyperpolarizability (β\u003csub\u003etot\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;1.517 x 10\u003csup\u003e\u0026minus;\u0026thinsp;30\u003c/sup\u003e esu) was found to be approximately \u003cb\u003e8 times greater\u003c/b\u003e than that of the standard urea molecule. These quantitative findings highlight the superior nonlinear optical (NLO) efficiency of Nicotinamide Trichloroacetate, making it a highly promising candidate for future applications in frequency conversion, optical switching, and laser-based technologies \u003cb\u003e[21, 30]\u003c/b\u003e. This theoretical roadmap paves the way for the experimental synthesis and structural characterization of this novel hybrid material. This theoretical roadmap paves the way for the experimental synthesis and TD-DFT based excited-state investigations of Nicotinamide Trichloroacetate in the near future\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthical Approval\u003c/strong\u003e \u003c/p\u003e\n\u003cp\u003eNot applicable. This study is a computational investigation and does not involve any studies with human participants or animals performed by any of the authors.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e \u003c/p\u003e\n\u003cp\u003eThe authors did not receive support from any organization for the submitted work. No funding was received to assist with the preparation of this manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting Interests\u003c/strong\u003e \u003c/p\u003e\n\u003cp\u003eThe authors have no relevant financial or non-financial interests to disclose.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; Contributions\u003c/strong\u003e \u003c/p\u003e\n\u003cp\u003eAll authors contributed to the study\u0026apos;s conception and design. Material preparation, data collection, and analysis were performed by \u003cstrong\u003eDr. Senthilkumar\u003c/strong\u003e.\u003cstrong\u003eK\u003c/strong\u003e .The first draft of the manuscript was written by \u003cstrong\u003eDr. Pugazhvadivu K.S. \u003c/strong\u003e and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData Availability Statement:\u003c/strong\u003e \u003c/p\u003e\n\u003cp\u003eAll DFT calculations for the Nicotinamide Trichloroacetate hybrid were performed using the \u003cstrong\u003eORCA program package\u003c/strong\u003e running on an \u003cstrong\u003eUbuntu Linux environment\u003c/strong\u003e. The corresponding input and output files, which confirm the structural and NLO properties discussed, have been made publicly accessible in the linked Google Drive repository.\u003c/p\u003e\n\u003cp\u003eAll raw data, including DFT output files and high-resolution images, have been made available via a public repository link: https://drive.google.com/drive/folders/17A3vhOEofjCnuR9jEqZ6fZbFdi8vMzkZ?usp=drive_link.\u003c/p\u003e\n"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eNeese F (2012) The ORCA program system. 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J Am Chem Soc 132(18):6498\u0026ndash;6506\u003c/span\u003e\u003c/li\u003e\u003c/ol\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-9418132/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9418132/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eIn this research, a novel organic\u0026ndash;inorganic hybrid material, Nicotinamide Trichloroacetate, was comprehensively investigated using Density Functional Theory (DFT) at the B3LYP/def2-SVP level of theory. The molecular geometry was fully optimized to its global minimum energy state, with the absence of imaginary frequencies confirming structural stability. \u003cb\u003eThe Frontier Molecular Orbital (FMO) analysis revealed a substantial HOMO\u0026ndash;LUMO energy gap of 10.1009 eV, indicating significant kinetic stability and effective intramolecular charge transfer (ICT) from the trichloroacetate donor to the nicotinamide acceptor moiety.\u003c/b\u003e The reactive sites were identified through Molecular Electrostatic Potential (MEP) mapping, which illustrated nucleophilic regions over the carboxylate oxygen atoms and electrophilic regions surrounding the amide hydrogen atoms. \u003cb\u003eVibrational characteristics were analyzed via simulated FT-IR spectroscopy, where the characteristic C\u0026thinsp;=\u0026thinsp;O stretching mode was identified at 1694 cm\u003c/b\u003e\u003csup\u003e\u003cb\u003e\u0026minus;\u0026thinsp;1\u003c/b\u003e\u003c/sup\u003e \u003cb\u003e(scaled), showing excellent agreement with theoretical expectations.\u003c/b\u003e Furthermore, the nonlinear optical (NLO) potential was assessed, yielding a \u003cb\u003ecalculated first-order hyperpolarizability β\u003c/b\u003e\u003csub\u003e\u003cb\u003etot\u003c/b\u003e\u003c/sub\u003e \u003cb\u003eof 1.517 x10\u003c/b\u003e\u003csup\u003e\u003cb\u003e\u0026minus;\u0026thinsp;30\u003c/b\u003e\u003c/sup\u003e \u003cb\u003eesu, which is approximately 8 times greater than that of the standard urea molecule (0.1947 x10\u003c/b\u003e\u003csup\u003e\u003cb\u003e\u0026minus;\u0026thinsp;30\u003c/b\u003e\u003c/sup\u003e \u003cb\u003eesu)\u003c/b\u003e These quantitative findings provide a robust theoretical foundation for the experimental development of Nicotinamide Trichloroacetate for future optoelectronic and laser-based applications.\u003c/p\u003e","manuscriptTitle":"Computational Investigation on the Structural, Spectroscopic (PXRD, FT-IR), and Nonlinear Optical (NLO) Properties of a Novel Organic-Inorganic Hybrid: Nicotinamide Trichloroacetate","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-04-27 07:07:28","doi":"10.21203/rs.3.rs-9418132/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":"e457d1fc-8239-4235-9f08-4b17de5c6377","owner":[],"postedDate":"April 27th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-05-05T09:41:31+00:00","versionOfRecord":[],"versionCreatedAt":"2026-04-27 07:07:28","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9418132","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9418132","identity":"rs-9418132","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}