Vibrational spectra, molecular structure, natural bond orbital, first order hyperpolarizability, TD-DFT and thermodynamic analysis of 4-amino-3-hydroxy-1-naphthalenesulfonic acid by DFT approach

Theoretical investigation of some 1,2,4-triazole-based molecules synthetized

In this study, theoretical calculations were made and interpreted to obtain chemical, nonlinear optical properties and antibacterial activity parameters of 14 registered heterocyclic 4, 5-dihydro-1H-1, 2, 4-triazole-5-one derivatives in the literature. For this purpose, first of all, 14 compounds registered in the literature and two main structures were optimized to find the minimum energy and the most stable structure by using the “B3LYP/6-311++G (d, p)” methods. HOMO–LUMO energies calculated from these optimized structures, energy differences and chemical parameters derived from HOMO–LUMO energies (I; Ionization potential, A; electron affinity, ΔE; Energy Gap, χ; electronegative σ; molecular softness, ω; Electrophilic Index, ε; Nucleophilic Index, μ; Chemical Potential) values were determined. In addition to chemical parameters, polar calculations were made for nonlinear optical properties, and it was evaluated whether the compounds could be optical materials. Finally, the antimicrobial properties of the molecules were calculated theoretically and compared with the experimental results by calculating the volume.

Synthesis, X-ray crystal structure, IR and Raman spectroscopic analysis, quantum chemical computational and molecular docking studies on hydrazone-pyridine compound: As an insight into the inhibitor capacity of main protease of SARS-CoV2

The characterization and synthesis of 3-chloro-2-{(2E)-2-[1-(4-chlorophenyl)ethylidene]hydrazinyl}pyridine (CCPEHP) was investigated in our study. Mass and UV-visible spectra were recorded in chloroform solvent. The CCPEHP molecule containing pyridine and chlorophenyl rings and hydrazone group crystallized in the triclinic system and P-1 space group. FTRaman and FTIR spectra were performed in the solid state. The optimized geometry of CCPEHP was computed by DFT/B3LYP method with 6-311 G (d, p) and 6-31 G (d, p) levels. The computed vibrational analysis, electronic absorption spectrum, electronic properties, molecular electrostatic potential, natural bond orbitals analysis and other calculated structural parameters were determined by using the DFT/B3LYP/6-31 G (d, p) basis set. The correlation of fundamental modes of the compound and the complete vibrational assignments analysis were studied. The strong and weak contacts were identified by using Hirshfeld surface analysis. The molecular modeling results showed that CCPEHP structure strongly binds to COVID-19 main protease by relative binding affinity of -6.4 kcal/mol.

Spectroscopic, quantum chemical and molecular docking studies on 1-amino-5-chloroanthraquinone: A targeted drug therapy for thyroid cancer

The DFT studies of the 1-Amino-5-chloro-anthraquinone (ACAQ) molecule have been carried out with extensive and accurate investigations of detailed vibrational and spectroscopic investigations and validated by experimentally. The optimized molecular structure and harmonic resonance frequencies were computed based on DFT/B3LYP method with 6-311G++(d,p) basis set using the Gaussian 09 program. The experimental and calculated vibrational wavenumbers were assigned on the basis of PED calculations using VEDA 4.0 program. The ¹³C NMR isotropic chemical shifts of the molecule were calculated using Gauge-Invariant-Atomic Orbital (GIAO) method in DMSO solution and compared with the experimental data. The absorption spectrum of the molecule was computed in liquid phase (ethanol), which exhibits л to л* electronic transition and compared with observed UV-Vis spectrum. Frontier molecular orbitals analysis shows the molecular reactivity and kinetic stability of the molecule. The Mulliken atomic charge distribution and molecular electrostatic potential surface analysis of the molecule validate the reactive site of the molecule. The natural bond orbital analysis proves the bioactivity of the molecule. Molecular docking analysis indicate that ACAQ molecule inhibits the action of c-Met Kinase protein, which is associated with the thyroid cancer. Hence, the present study pave the way for the development of novel drugs in the treatment of thyroid cancer.

Synthesis, growth, optical, mechanical, thermal, dielectric and third order nonlinear optical properties of cyclohexylamine derivative single crystals

The materials of Cyclohexylamine with 1,5-naphthalenedisulfonic acid and 3,5-dinitrosalicylic acid were used to synthesize the bis(cyclohexylammonium)-1,5-naphthalenedisulfonate (CA15NS) and bis(cyclohexylammonium)-3,5-dinitrosalicylate (CA35NS) compounds and single crystals of these compounds were grown successfully by low temperature solution growth technique. Crystal systems of the samples were identified for both the samples of CA15NS and CA35NS by the obtained unit cell parameters of the grown crystals which is determined by single crystal X-ray diffraction (SCXRD) analysis, the crystals of CA15NS and CA35NS are crystallized in monoclinic crystal structures. The powder X-ray diffraction (PXRD) analysis also was carried out for the title samples. The formations of the charge-transfer functional groups and the modes of vibrations of CA15NS and CA35NS have been confirmed by FT-IR and FT-Raman spectral analyses. The UV-Vis-NIR spectrum was carried out to find the optical behavior of the prepared crystals. The crystal of CA15NS has 232 nm and CA35NS has 207 nm as cut-off wavelength. The influences of mechanical and dielectric behavior in the crystals of CA15NS and CA35NS were investigated by means of Vickers microhardness test and dielectric study, respectively. By the thermo gravimetric analyses, the stability of the materials have been estimated for the title samples. Third order nonlinear optical study has also been studied by Z-scan technique.

Synthesis, characterization, anti-diabetic potential and DFT studies of 7-hydroxy-4-methyl-2-oxo-2H-chromene-8-carbaldehyde oxime

A new compound named 7-hydroxy-4-methyl-2-oxo-2H-chromene-8-carbaldehyde oxime (7-Oxime) was synthesized and characterized by FT-IR, FT-Raman, ¹H NMR and ¹³C NMR techniques. The conformer possibilities were studied to find the most stable conformer and its molecular geometry. Then, the dimer form of the most stable monomer was built and optimized. Density functional theory (DFT) B3LYP method with 6-311++G(d,p) basis set was applied to analyze the molecular electrostatic potential (MEP), HOMO and LUMO orbitals, the vibrational wavenumbers, the infrared intensities, the Raman scattering activities and several thermodynamic properties (at different temperatures). The stability of the molecule derived from hyperconjugative interactions and charge delocalization has been analyzed by using natural bond orbital (NBO) analysis. In order to find the possible inhibitory activity of 7-Oxime, an accurate molecular blind docking simulation was performed. The results indicated that the mentioned compound has a good binding affinity to interact with the active sites of human α-glucosidase and α-amylase. For the first time, our computational finding suggests that this compound has a potential to be used as a supplementary agent in the pre-management of diabetes mellitus.

Vibrational spectra (experimental and theoretical), molecular structure, natural bond orbital, HOMO-LUMO energy, Mulliken charge and thermodynamic analysis of N'-hydroxy-pyrimidine-2-carboximidamide by DFT approach

The FT-IR, FT-Raman, (1)H, (13)C NMR and UV-Visible spectral measurements of N'-hydroxy-pyrimidine-2-carboximidamide (HPCI) and complete analysis of the observed spectra have been proposed. DFT calculation has been performed and the structural parameters of the compound was determined from the optimized geometry with 6-311+G(d,p) basis set and giving energies, harmonic vibrational frequencies and force constants. The results of the optimized molecular structure are presented and compared with the experimental. The geometric parameters, harmonic vibrational frequencies and chemical shifts were compared with the experimental data of the molecule. The title compound, C5H6N4O, is approximately planar, with an angle of 11.04 (15)°. The crystal structure is also stabilized by intermolecular N-H⋯O, N-H⋯N, O-H⋯N, C-H⋯O hydrogen bond and offset π-π stacking interactions. The influences of hydroxy and carboximidamide groups on the skeletal modes and proton chemical shifts have been investigated. Moreover, we have not only simulated highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) but also determined the transition state and band gap. The kinetic, thermodynamic stability and chemical hardness of the molecule have been determined. Complete NBO analysis was also carried out to find out the intermolecular electronic interactions and their stabilization energy. The thermodynamic properties like entropies and their correlations with temperatures were also obtained from the harmonic frequencies of the optimized structure.

Density functional theory studies on molecular structure, vibrational spectra and electronic properties of cyanuric acid

The present work has been carried out a combined experimental and theoretical study on molecular structure, vibrational spectra and NBO analysis of cyanuric acid. The FT-IR (100-4000cm(-1)) and FT-Raman spectra (400-4000cm(-1)) of cyanuric acid were recorded. In DFT methods, Becke's three parameter exchange-functional (B3) combined with gradient-corrected correlation functional of Lee, Yang and Parr (LYP) by implementing the split-valence polarized 6-31G(d,p) and 6-31++G(d,p) basis sets have been considered for the computation of the molecular structure optimization, vibrational frequencies, thermodynamic properties and energies of the optimized structures. The density functional theory (DFT) result complements the experimental findings. The electronic properties, such as HOMO-LUMO energies and molecular electrostatic potential (MESP) are also performed. Mulliken population analysis on atomic charges is also calculated. The first order hyperpolarizability (βtotal) of this molecular system and related properties (β, μ and Δα) are calculated using DFT/B3LYP/6-31G (d,p) and B3LYP/6-311++G(d,p) methods. The thermodynamic functions (heat capacity, entropy and enthalpy) from spectroscopic data by statistical methods were also obtained for the range of temperature 50-1000K.

A DFT analyses for molecular structure, electronic state and spectroscopic property of a dithiolene tungsten carbonyl complex

Bis(dithiolene) tungsten carbonyl complex, W(S2C2Ph2)2(CO)2 was successfully synthesized and the structure, frontier molecular orbital and optical properties of the complex were investigated theoretically using density functional theory calculations. The investigation started with a molecular structure construction, followed by an optimization of the structural geometry using generalized-gradient approximation (GGA) in a double numeric plus polarization (DNP) basis set at three different functional calculation approaches. Vibrational frequency analysis was used to confirm the optimized geometry of two possible conformations of [W(S2C2Ph2)2(CO)2], which showed distorted octahedral geometry. Electronic structure and optical characterization were done on the ground states. Metal to ligand and ligand to metal charge transfer were dominant in this system.