Potential Energy Distribution Analysis Research Articles

Exploring odd-even sensitivity in m.OnO.m liquid crystal compounds: A comprehensive study using DFT analysis

In this article, a comprehensive investigation into a series of liquid crystalline compounds belonging to the α,ω-bis(4-alkylanilinebenzylidene-4′-oxy)alkane (m.OnO.m) family has been conducted to unravel their intricate molecular characteristics. The computational investigations employing DFT/B3LYP/6-311G(d,p) level delve into the odd–even effect, exploring how the presence of spacer units influences the structural, electronic, and vibrational properties of these compounds. Optimization analyses reveal the minimum energy configurations, offering valuable insights into spatial arrangements and symmetry. Visualization of molecular structures emphasizes a distinctive odd–even effect, with compounds exhibiting either U-shaped or Z-shaped configurations based on the parity of spacer units. Charge distribution maps further elucidate electronic intricacies, showcasing the interplay of charges among different atoms. Thermodynamic properties and frontier orbital analysis providing a nuanced understanding of the compounds behavior. NLO parameters exhibited a consistent odd–even effect. Potential Energy Distribution (PED), IR, and Raman spectra analysis, provided a detailed symphony of stretching, bending, and torsional motions. UV–Vis absorption spectra uncover distinctive electronic transitions within each compound. In essence, this research sheds light on the profound impact of spacer units, shaping the structural, electronic, and vibrational characteristics of the liquid crystalline compounds. The odd–even effect emerges as a central theme, weaving a captivating narrative of molecular dynamics within this intriguing class of materials.

Spectroscopic and computational study of Favipiravir-Adenine cocrystallization biomolecular complex

The research focuses on the structural investigation of biomolecules and biomolecular complexes using the DFT method, spectroscopic techniques, and determining cocrystal formation. The significant difficulties in making new drug products are low oral bioavailability and poor aqueous solubility. However, the co-crystallization of biomolecules can enhance their solubility without changing their pharmacological properties. The optimized structure of the molecules is obtained using the B3LYP/6–311++G(d,p) basis set within the framework of Density Functional Theory (DFT). Various vibrational techniques such as Fourier Transform Infrared (FTIR), Raman, and Surface-Enhanced Raman Spectroscopy (SERS) are employed to characterize the monomers and their interacting system. Possible vibrational assignments along with Potential energy distribution (PED) analysis are carried out using Vibrational Energy Distribution Analysis (VEDA). Natural Bond Orbital (NBO), Non-Linear Optical (NLO), Non-Covalent Interaction (NCI), and Atoms in Molecule (AIM) study are carried out to understand the interacting mechanism in the Favipiravir-Adenine biomolecular complex. The study shows that there is charge transfer through inter and intramolecular interaction in the complex. The binding energy of protein and Ligand is investigated using the Autodock tool for the molecular docking method and the negative value of binding energy – 4.36 kcal/mol of Favipiravir-Adenine biomolecular complex exclaims good binding affinity with the chosen protein 6LU7. Lipinski's criteria for druglikeness also claim that monomers and synthesized biomolecular complexes have the potential to influence drugs with good oral bioavailability. Cocrystal formation is confirmed by the X-ray diffraction pattern. The Protox II software claims that the toxicity of the drug and synthesized biomolecular complex is class IV.

Investigation of intermolecular interactions in butyl acetate using vibrational spectroscopy and non-empirical calculations

In this work, on the example of butyl acetate, the nature of intermolecular interactions was studied using vibrational spectroscopy (Raman and FTIR) and non-empirical calculations. The geometric structures of the most stable dimer and trimer aggregates of butyl acetate were optimized using the Density Functional Theory (DFT) method based on the B3LYP/6-311++G(d,p) basis set. Molecular aggregations in liquid butyl acetate were shown to be formed by dipole-dipole interactions and weak C-H…O hydrogen bonds. A potential energy distribution (PED) analysis was performed for the butyl acetate molecule, and experimental and calculated frequencies were found to be in good agreement. Frontier molecular orbitals such as the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of the butyl acetate molecule were analyzed.

Molecular structure properties, quantum computational, electronic, charge analyses and biological (drug-likeness and docking) studies on anti-inflammatory drug molecule of Balsalazide

(E)–5-([4-(2–carboxyethylcarbamoyl) phenyl] diazenyl)-2-hydroxybenzoic acid (Balsalazide) was scrutinized theoretically using quantum computational calculation. FT-IR, UV–vis., and optimized structure data were collected utilizing the DFT approach with the B3LYP functional and 6-311++G(d,p) basis set. The wave number computations and improved molecular geometry were carried out in the gas phase. Utilizing VEDA analysis, the potential energy distribution analysis PED of the title chemical was carried out. Additionally, experiments on chemical reactivity and molecular electrostatic potential (MEP) were carried out. Researchers employed the electron localization function (ELF) to demonstrate electron delocalization in the molecule. Topological and Mulliken charge distribution investigations were other subjects. Intermolecular charge transfer was interpreted using natural bond orbital analysis (NBO). RDG analysis used electron concentration as a basis. To clarify how the electronics-based transmissions in the UV–vis spectral range of several solvents (Gas, Water, DMSO, Ethanol, and Acetone) were determined, DFT analysis was also employed. Maximum wavelength (λ) absorbance and band-gap energy estimates for Balsalazide were calculated for different solvents. The electrophilicity index is used to theoretically explain bioactivity, while molecular docking is used to show how a ligand interacts with a protein. Through molecular docking, the Transcription classified proteins of 2Q1V and 4ME0 are examined. The drug-likeness of the molecule revealed its nature.

Formation of Hydrogen Bonds and Vibrational Processes in Dimethyl Sulfoxide and Its Aqueous Solutions: Raman Spectroscopy and Ab Initio Calculations

The intermolecular interaction in dimethyl sulfoxide (DMSO), which is a strong solvent, and its manifestation in vibrational spectra are studied by means of Raman spectroscopy and ab initio calculations. The optimal structure and vibrational spectra of DMSO monomer, dimer, and trimer, as well as complexes of DMSO with water molecules, are calculated, and the potential energy distribution (PED) analysis is carried out. In the Raman spectra of DMSO and its water solutions, a red shift of the S=O stretching band due to the conventional hydrogen bonding and a blue shift of the C–H stretching band due to non-classical hydrogen bonding are detected. The MEP surfaces (changes in the charge distribution) of DMSO monomer, dimer, and DMSO–water cluster are plotted.

New group of inorganic salts of 1,3-diaminoguanidinium(1+) cation – crystal structures, vibrational spectra, linear and nonlinear optical properties

In the search for new molecular crystals for nonlinear optics (NLO), nine inorganic salts containing the 1,3-diaminoguanidinium(1+) cation as a promising organic “Y-aromatic” carrier of NLO properties were prepared and studied. Crystal structures of eight new salts, namely 1,3-diaminoguanidinium(1+) chloride (P21/c), hypophosphite (P21/c), hydrogen phosphite (P-1), dihydrogen phosphate (P21/c), hydrogen phosphate (P21/m), nitrite (P-1), sulfite (Pbcm) and chlorate (P21/c) were solved by the single crystal X-ray diffraction. The crystal structures contain centrosymmetric arrangements of pairs of counterions assembled into hydrogen-bonded undulated sheets. The charge-assisted hydrogen bonds in the resulting hydrogen bond networks are accommodated by the conformation of the 1,3-diaminoguanidinium(1+) cation as a hydrogen bond donor. All salts were also characterized by powder X-ray diffraction. The vibrational spectra (FTIR and Raman) were studied for all newly prepared salts and the previously published non-centrosymmetric sulfate (P6122). The assignment of the vibrational bands of these hydrogen-bonded crystals is derived from quantum-chemical computations (B3LYP/6-311G+(d,p) along with the Potential Energy Distribution analysis) concerning isolated 1,3-diaminoguanidinium(1+) cation and the results of correlation analysis involving present inorganic anions. The linear and nonlinear optical properties of the only non-centrosymmetric salt – 1,3-diaminoguanidinium sulfate – were studied. This uniaxial positive crystal is optically transparent down to 230 nm, and refractive indices (ne = 1.65 and no = 1.56) have been determined at 532 nm. The dispersion curves of the refractive indices were also calculated by the Q(LFT) procedure in the 532–1907 nm region. The experimentally determined (using 800 and 1000 nm laser irradiation) very low efficiency of second harmonic generation (i.e., ∼1% of KDP), which is consistent with the Kleinman symmetry assumption for the P6122 space group, limits further use of this crystal for second-order NLO applications.

Unraveling the structure–property relationship of a chalcone-based push–pull molecule for optical limiting application in high-powered laser

In this work, the optical limiting response of a highly π-conjugated push–pull chalcone derivative (2E)-3-(2,3-dimethoxyphenyl)-1-(3-nitrophenyl)prop-2-en-1-one (abbreviated as 3DPNP) has been investigated. The structure–property relationship of 3DPNP was explored through spectroscopic investigation and quantum chemical computations. The existence of weak-non-covalent interactions and charge transfer species that responsible for the chemical stability of 3DPNP were studied by AIM and NBO analyses. The quantitative and qualitative analysis of vibrational and electronic contribution to non-linear optical (NLO) response of 3DPNP were discussed in detail. The normal vibrational modes associated with a change in the dipole moment, polarizability, first- and second-order hyperpolarizabilities of 3DPNP were identified using DFT calculations followed by potential energy distribution (PED) analysis using Gaussian 09 W software and Gar2ped program, respectively. The changes in the NLO parameters with respect to the varying frequencies and electric dipole fields were studied. The abrupt changes in the NLO properties were noticed when the frequency doubled, confirming the second harmonic generation (SHG) efficiency of 3DPNP. From the non-linear absorption and refraction studies through the z-scan experiment, the optical limiting threshold value of 3DPNP is determined to be 3.26 kJ/cm2, which shows the suitability of the material for optical limiting applications in the continuous wave (CW) laser regime.

Substituted Benzalacetophenone Molecules: A Computational Investigation of Structural, PED & Non‐Linear Optical Properties

AbstractThis protocol presents a complete theoretical study on the substituted benzalacetophenone molecules. In this study, eighteen chalcone derivatives 1–18 were evaluated with respect to their first‐ and second‐order hyperpolarizability parameters. For this purpose, the molecular geometries of 1–18 were optimized using set 631 g (d,p) and hybrid functional B3LYP. Spectroscopic characterizations for 1–18 were executed through the calculations of IR, UV‐Vis, 1H NMR and 13C NMR spectra. The quantum chemical parameters such as chemical potential, chemical hardness, electronegativity and electrophilicity indexes were obtained using the frontier molecular orbital (FMO) energies. The potential energy distribution (PED) analysis was used to provide a detailed assignment of vibrational bands. Important contributions to electronic absorption bands from FMOs were also evaluated. The distribution of FMOs to the whole molecule was investigated to determine the nature of electronic charge transfers in the target structures. The static and dynamic first‐ and second‐order hyperpolarizability parameters for 1–18 were calculated by using CAM‐B3LYP/6‐31++G(d,p). The static β and γ were calculated at the ranges of 1.348–2.967×10−29 esu and 82.50–136.2×10−36 esu. This wide range of β and γ values indicates that chalcone derivatives with rational substitution may be promising candidates for first‐ and second‐order NLO applications. The findings of this study contribute to the understanding of the relationships between molecular structure and non‐linear optical properties, thus paving the way for the design of new materials with improved non‐linear optical properties.

Synthesis, structural and spectral investigations of an optically active E-N′-(3,4-dimethoxybenzylidene)− 4-fluorobenzohydrazide crystal

Hydrazines represent a group of compounds with pronounced pharmacological activities, along with their possible use of optically active materials. In this contribution, E-N′-(3,4-dimethoxybenzylidene)− 4-fluorobenzohydrazide (DBF) was synthesized and chemically characterized by X-ray crystallography, IR, Raman, UV–VIS, and NMR spectroscopies. The intermolecular interactions governing the stability of the crystal were investigated by the Hirshfeld surface analysis. The structure optimization was performed starting from a crystallographic one. The highest resemblance between experimental and theoretical bond lengths and angles was obtained for the structure at M06–2X/6–311 + +G(d,p) level of theory. The Natural Bond Orbital (NBO) and Quantum Theory of Atoms in Molecules (QTAIM) analyses outlined the most important intramolecular interactions. The IR and Raman spectra vibrational peaks were assigned based on the Potential Energy Distribution (PED) analysis. Theoretical methods with high correlation factors and low mean absolute error reproduced the NMR chemical shifts. The excited state optimization of DBF with a difference of several nm modelled the peak at 330 nm in the experimental UV–VIS spectrum. The Condensed Fukui functions outlined the most active positions for electrophilic, neutrophilic, and radical attacks. The non-linear optical (NLO) Z-scan experiment determined the absorption coefficient and nonlinear refractive index, concluding that DBF can be used as NLO material. The ECOSAR prediction of toxicity showed that the material could be potentially dangerous for aquatic organisms.

Crystal structure, vibrational and chemical properties and phase transitions in Glycyl-DL-Aspartic acid and Glycyl-DL-Aspartic acid monohydrated.

In this paper, the structural and vibrational analysis of the dipeptides glycyl-DL- aspartic acid hydrate (H-Gly-DL-Asp-OH.H2O) crystal, with P1¯ (C11) triclinic symmetry and glycyl-DL- aspartic acid (H-Gly-DL-Asp-OH) crystal, with Cc space group (Cs4) monoclinic structure, were studied. The crystallographic structures of these molecules were determined by single-crystal X-ray diffraction. Changes in the powder X-ray diffraction patterns of H-Gly-DL-Asp-OH.H2O as a function of the temperature were recorded. After 403 K, the water molecule detaches itself from H-Gly-DL-Asp-OH.H2O, causing its symmetry to change from triclinic to monoclinic. The normal modes of vibration were analyzed through calculations based on Density Functional Theory (DFT) using the B3LYP functional with the Gaussian bases 6–311++G (d,p) and potential energy distribution (PED) analysis. These results, together with literature data and Raman and infrared (IR) spectroscopy measurements, allowed the identification of the various vibrational normal modes. Furthermore, the effect of high pressure on H-Gly-DL-Asp-OH.H2O was studied by Raman spectroscopy experiments. The results obtained from the Raman spectra at high pressures indicate changes around 2.1 and 4.5 GPa, such as the disappearance, splitting and emergence of some modes, as well as discontinuities in the evolution of wavenumbers of several normal modes of vibration. Such changes involved modes localized in the region of external modes, while others involved molecular backbone modes and modes that participate in hydrogen bonding. The changes were related to small conformational changes associated with H bonds and small deformations in hydrated dipeptide molecules.

Synthesis, crystallographic and spectroscopic investigation, chemical reactivity, hyperpolarizabilities and in silico molecular docking study of (Z)-2N-(tert‑butylimino)-3N’-(4-methoxyphenyl) thiazolidin-4-one

This study presents the results related to the synthesis of (Z)-2N-(tert‑butylimino)-3N’-(4-methoxyphenyl) thiazolidin-4-one (TMTh) and its characterization by X-ray diffraction and spectroscopic techniques. The compound was characterized by 1H and 13C NMR and FT-IR spectroscopy. According to the single-crystal X-ray diffraction (SC-XRD) analysis, the title compound belongs to the centrosymmetric I2/a space group of the monoclinic system with 8 molecules in the unit cell. Using density functional theory (DFT) at the B3LYP/6-311 G (d,p) level, the optimized structure of TMTh was predicted. The structure was described by the geometric parameters confirming a good consistency between experimental and theoretical structural results. The identification of weak interactions and their contributions, including the C − H···O and C − H···S hydrogen bonds, and van der Waals (vdW) interactions, which are necessary for maintaining the crystal packing, were also addressed by the use of Hirshfeld surface (HS) and RDG analyses. From the HS, the major contribution with 56.3% is due to H···H contacts. To obtain and identify the vibration frequencies and their assignments, the PED (Potential Energy Distribution) analysis of the title compound was carried out. The results were then confirmed and compared to the experimental FT-IR spectral data. The 1H and 13CNMR chemical shifts were also calculated to compare and complement the experimental results. To highlight the compound's absorption behavior, the electronic transitions are assigned according to the time-dependent density functional theory (TD-DFT) outcomes and confirmed the electronic circular dichroism (ECD) spectrum. The experimental and theoretical UV–vis spectra are also provided suggesting a strong π→π* transition at 250 nm. Charge transfer inside the molecule was considered using the frontier molecular orbitals (FMOs) investigations, and ELF, LOL, and MEP distribution maps were also investigated. The HOMO and LUMO energies were used to estimate the chemical reactivity descriptors and the corresponding energy gap is 2.67 eV. The nonlinear optical (NLO) activity of the compound has been analyzed, and the corresponding properties have been evaluated. The most important first and second order hyperpolarizabilities calculated with BPV86 functional were found to be 5.58 × 10−30 esu and 26.01 × 10−36 esu, respectively The present study deals also with the in silico ADMET study using molecular docking and the SwissADME web tool to determine the physicochemical and pharmacokinetic properties. The biological activity was performed against the gluconate 2-dehydrogenase protein with 5U9P, 4HP8, 4Z9X, 1VL8, 4IBO and 3O03 receptors.

Studies on crystal growth, experimental, structural, DFT, optical, thermal and biological studies of 3-hydroxy-4-methoxybenzaldehyde single crystals

The organic 3-hydroxy-4-methoxybenzaldehyde single crystal has been grown by the slow evaporation technique. Single crystal X-ray diffraction (XRD) study shows that the grown crystal belongs to a monoclinic crystal system with centrosymmetric space group P21/c. The spectral analysis of 3-hydroxy-4-methoxybenzaldehyde calculations was performed with the help of DFT at the B3LYP/6-311 + G(d,p) level of theory. The experimental results of FTIR and FT-Raman were compared with the computational results. Detailed interpretations of the vibrational spectra were carried out with the aid of vibrational energy distribution analysis using potential energy distribution (PED) analysis and vibrational wavenumber scaled by the WLS (Wavenumber Linear Scaling) method. The natural bond orbital (NBO) analysis was carried out to identify intramolecular hydrogen bonding. The optical properties of the grown crystal were analyzed by UV–Visible studies. Photoluminescence studies show that the high-intensity peak observed around 410 nm. The laser damage threshold value of the grown crystal has been determined using an Nd:YAG laser operating at 1064 nm. The HOMO (Highest Occupied Molecular Orbital) – LUMO (Lowest Unoccupied Molecular Orbital) was used to identify the energy gap. Hirshfeld Surface (HS) analysis was used to determine the intermolecular interactions. The thermal properties of the grown crystal were performed by Thermogravimetric (TG) and Differential thermal analyses (DTA). The kinetic and thermodynamic parameters were calculated. The surface morphology of the grown crystal was studied by using Scanning Electron Microscopy (SEM) analysis. The antibacterial and antifungal studies were analyzed.

Structural, spectroscopic, molecular docking, ADME, molecular dynamics studies of Val-Trp dipeptide

Hypertension is a significant risk factor for various diseases, especially heart, brain, and kidney diseases. It is known that many peptides have the property of lowering blood pressure and determine as ACE inhibitors. The purpose of this study is to obtain information about the molecular structure of Val-Trp (L-valyl-L-tryptophan), which is one of the antihypertensive peptides, by molecular mechanical, quantum mechanical, and spectroscopic methods (FT-IR and Raman). Also, it is aimed to investigate the interactions of Val-Trp dipeptide with receptors related to hypertension and to determine the pharmacokinetic profile due to the potential of the peptide to be a drug candidate. The peptide structure was optimized by DFT/B3LYP/6-311++G(d,p) basis set, then vibrational wavenumbers, molecular electrostatic potential (MEP), HOMO-LUMO (highest occupied molecular orbital- lowest unoccupied molecular orbital), NBO (natural bond orbital) analyzes were performed. The assignment of fundamental theoretical vibration wavenumbers was carried out with potential energy distribution analysis (PED). After the structural analyzes of the peptide were performed, the interactions of the peptide with Angiotensin-converting enzyme (ACE), Angiotensin II Receptor Type 1 (AT1R) and Renin were investigated by molecular docking study. Then, the molecular dynamic (MD) simulation of the peptide-ACE complex with the best binding affinity in the molecular docking studies was carried out for 50 ns. ADME (absorption, distribution, metabolism, and excretion) analysis of Val-Trp dipeptide was performed. In support of the studies carried out, enlightening information about the feasibility of the antihypertensive drug of Val-Trp dipeptide with the help of the ADME profile was presented to the literature.Communicated by Ramaswamy H. Sarma

3-(dimethylamino)dibenzothiophene (3-DMADBT): Synthesis, characterization, crystallographic study, Quantum chemical calculations, Hirshfeld surface analysis and FT-IR spectroscopy

The 3-(dimethylamino) dibenzothiophene (3-DMADBT) has been synthesized and characterized by X-ray single crystals diffraction (XRD), FT-IR, 1H NMR, Elemental analysis, and Melting point determination. The density functional (B3LYP) and Hartree-Fock (HF) methods with a 6–31 G (d,p) level were established to calculate the parameters of molecular geometry, normal mode frequencies and the related vibrational assignments, and 1H chemical shift values for gage-including atomic orbitals (GIAO) of 3-DMADBT in its ground state. Potential energy distribution (PED) analyses were used to assign vibrations. The tested chemical crystallizes in an orthorhombic crystal structure with a space group of P212121 and unit cell dimensions of a = 6.0750 (5) Å, b = 8.9566 (6) Å, c = 21.2622 (11) Å, and V = 1156.90 (14) Å3. The calculated data shows that optimized geometries can accurately reproduce the crystal structure. The experimental results accord well with the theoretical vibrational frequencies and chemical shift values from 1H NMR. Furthermore, the compound's Mulliken charge distribution and molecular electrostatic potential maps (MEP) have been developed. The energy gap (∆E), electron affinity (A), ionization potential (I), chemical potential (µ), global hardness (η), and global electrophilicity (w) are all calculated using the HOMO-LUMO analysis. In addition, the Hirshfeld surface analysis is used to determine interactions in the crystal structure.

Structural, Spectroscopic, Quantum Chemical, RDG, AIM, ELF, Fukui, O–H…N Hydrogen Bonding and NLO Activity of 2-Hydroxy-2-Phenyl Acetophenone Oxime: Experimental and Theoretical Approach

In the present work, organic 2-hydroxy-2-phenyl acetophenone oxime (2H2PAO) single crystal was synthesized and characterized by FT-IR, FT-Raman, UV-Vis, NMR spectra. The optimized geometrical parameters were computationally obtained at DFT/B3LYP level of theory. Harmonic vibrational frequencies were calculated and the spectral assignments have been done by potential energy distribution (PED) analysis using NCA method. The natural bond orbital (NBO), atoms in molecule (AIM) and Hirshfeld surface analysis and RDG were applied to evaluate the relative strength of hydrogen bond interactions and represent their effect on the stabilities of molecular arrangement. The chemical stability and NLO activity of title compound were evaluated by HOMO-LUMO analysis. MEP and Fukui function analysis recognizes the nucleophilic and electrophilic regions of the molecule and the chemical implication of molecule have been explained using ELF and LOL analysis. Photo-excitation of 2H2PAO has been examined to understand its light emitting behavior. Thermal stability of the grown crystal was examined by TG/DTA analysis to understand the withstanding temperature of 2H2PAO.

Promoting antihepatocellular carcinoma activity against human HepG2 cells via pyridine substituted palladium complexes: in vitro evaluation and QSAR studies.

Bis(4-(4-nitrobenzyl)pyridine)dichloropalladium(II), [PdCl2L12], bis(2-amino-5-bromopyridine)dichloropalladium(II), [PdCl2L22], bis(2,4-dimethylpyridine)dichloropalladium(II), [PdCl2L32], bis(3,4-dimethylpyridine)dichloropalladium(II), [PdCl2L42] were prepared. The spectroscopic techniques (FT-IR and 1H-NMR, 13C-NMR) were used to characterize the compounds. Theoretical calculations were used to validate the experimental results. The LanL2DZ-based DFT/B3LYP method was used to define the most stable possible molecular structure for the complexes. Potential energy distribution analysis was performed to determine the theoretical vibration bands of the complexes. Molecular electrostatic potential maps, boundary molecular orbitals and Mulliken charge distribution were used to determine the active sites of the molecules. The interaction mechanisms between the complexes and liver cancer protein were investigated via molecular docking. The study on the antiproliferative effects of these complexes on hepatocellular carcinoma cells (HepG2) showed that they are potent candidates for use against this liver cancer cell line.

Structural, spectroscopic, quantum chemical, and molecular docking study towards cartilage protein of (3E,3′E)-3,3′-(1,4-phenylenebis(azanediyl))bis(cyclohex-2-en-1-one)

This article presents the results of the structural and spectroscopic analysis of (3E,3′E)-3,3′-(1,4-phenylenebis(azanediyl))bis(cyclohex-2-en-1-one) by the means of IR, Raman, NMR, and Density functional theory methods. The structure of the compound was optimized at the B3LYP/6-311++G(d,p) level of theory. The NMR spectra were predicted using the Gauge Independent Atomic Orbital approach. The mean absolute differences between experimental and theoretical chemical shifts were 0.44 and 2.3 ppm for 1H and 13C NMR spectra thus proving the applicability of the chosen level of theory. The vibrational (IR and Raman) spectra were assigned based on the optimized structure following the Potential Energy Distribution (PED) analysis. The intermolecular interactions governing the stability of the compound were investigated by the Natural Bond Orbital and Quantum Theory of Atoms in Molecules analyses. The active positions in the compound were assessed by the Fukui functions calculation and Molecular electrostatic potential map. The inhibitory activity of the compound was analyzed by molecular docking toward cartilage proteins. This activity, along with the groups included in interactions, proved the activity of various parts of the molecule. The inhibitory activity was higher than that of a native ligand. The ecotoxicity assessment proved low toxicity towards aquatic organisms. These results show the high potential of enaminone derivatives obtained under mild conditions.

Quantum Chemical Characterization of 4-({4-[Bis(2-Cyanoethyl)Amino]Phenyl}Diazinyl)Benzene Sulfonamide by Ab-Initio Calculation

4-({4-[Bis(2-cyanoethyl)amino]phenyl}diazinyl)benzene sulfonamide is the azo dye material which has general application in the textile industry. Experimentally, it has been synthesized and geometrically characterized by G. Gervasio et al. In this study, the theoretical analysis has been calculated by using the ab-initio method based on the Density Functional Theory/B3LYP/6-311G(d,p) to characterize the structural, spectroscopy, and electronic properties of the title azo dye. Its molecular geometries are in good agreement with those of available experimental data. 129 vibrational modes have been specified with stretching, in-plane-bending, out-of-plane-bending, and torsion vibration modes by the Potential energy Distribution analysis. The ultraviolet spectra appear in a single peak for six common solvation at 429 nm. The Gauge-Invariant Atomic Orbital approach has been applied to predict the chemical shifts of 1H and 13C NMR only in DMSO solvation. The electronic properties have been investigated such as the energy bandgap (3.34 eV), ionization potential energy (6.24 eV), electron affinity (2.90 eV), electronegativity (4.57 eV), and chemical hardness (1.67 eV) by using the Frontier Molecular Orbital Theory from the energy interaction of the Lowest Unoccupied Molecular Orbital and Highest Occupied Molecular Orbital. The characterization of the title azo dye is conducted theoretically for the first time in this study.

Structural and spectroscopic analysis of L‐Proline monomer and dimer by DFT approach

AbstractIn this work we have analyzed the Fourier Transform Infrared (FTIR), Raman and Surface Enhanced Raman Spectra (SERS) of L‐Proline. The molecule under consideration L‐Proline in monomer and dimer states were optimized using DFT/B3LYP and DFT/M06‐2X methods with 6‐31G (d,p) basis set. In order to correlate the experimental SERS spectra we have calculated the Raman spectra of L‐Proline monomer and dimer with silver (Ag) clusters using Density Functional Theory (DFT) with B3LYP functional and LANL2DZ basis set. The vibrational spectra were interpreted by using vibrational energy distribution analysis (VEDA) program and potential Energy Distribution (PED) analysis of the vibrational modes have been performed to have a clear picture of the fragments of different states of the molecule. The equilibrium molecular geometry, harmonic vibrational wavenumbers, Frontier molecular orbitals, Mulliken charges, energy parameters and various bonding features have also been computed.

First and second order hyperpolarizabilities of flavonol derivatives: A density functional theory study

In this study, seventeen flavonol derivatives (1–17) were evaluated with regard to their first- and second-order hyperpolarizability parameters. For this purpose, the molecular geometries of 1–17 were optimized by using B3LYP/6–311++G(d,p) level. Spectroscopic characterizations for 1–17 were executed through the calculations of IR, UV–vis, 1H NMR and 13C NMR spectra. The quantum chemical parameters such as electronegativity, chemical hardness, chemical potential and electrophilicity indexes were obtained by using the frontier molecular orbital (FMO) energies. The potential energy distribution (PED) analysis was used to provide a detailed assignment of vibrational bands. Important contributions to electronic absorption bands from FMOs were also evaluated. The distribution of FMOs to the whole molecule was investigated to determine the nature of electronic charge transfers in 1–17. The static and dynamic first- and second-order hyperpolarizability parameters for 1–17 were calculated by using B3LYP/6–311++G(d,p) level. The static β and γ were calculated at the ranges of 9.8279–0.0303 × 10-29 esu and 80.200–268.40 × 10-36 esu. The dynamic β and γ (ω = 532 nm) were also obtained in the field of 1.0440–71.786 × 10-29 esu and 306.20–3607.00 × 10-36 esu. This wide range of β and γ values indicate that flavonol derivatives with rational substitution may be promising candidates for first- and second-order NLO applications.