Vibrational spectra, UV and NMR, first order hyperpolarizability and HOMO-LUMO analysis of 2-amino-4-chloro-6-methylpyrimidine

WOS: 000310395800109PubMed ID: 22902579The solid phase FTIR and FT-Raman spectra of 2-amino-4-chloro-6-methylpyrimidine (2A4Cl6MP) have been recorded in the regions 400-4000 and 50-4000 cm(-1). respectively. The spectra have been interpreted interms of fundamentals modes, combination and overtone bands. The structure of the molecule has been optimized and the structural characteristics have been determined by density functional theory (B3LYP) method with 6-311++G(d,p) as basis set. The vibrational frequencies were calculated and were compared with the experimental frequencies, which yield good agreement between observed and calculated frequencies. The infrared and Raman spectra have also been predicted from the calculated intensities. H-1 and C-13 NMR spectra were recorded and H-1 and C-13 nuclear magnetic resonance chemical shifts of the molecule were calculated using the gauge independent atomic orbital (GIAO) method. UV-Vis spectrum of the compound was recorded in the region 200-400 nm and the electronic properties HOMO and LUMO energies were measured by time-dependent TD-DFT approach. Nonlinear optical and thermodynamic properties were interpreted. All the calculated results were compared with the available experimental data of the title molecule. (c) 2012 Elsevier B.V. All rights reserved

Spectroscopic (FTIR, FT-Raman, UV–Vis) studies, NMR, NBO analysis, molecular docking studies on 2-cyano-5-fluoropyridine and 3-cyano-2-fluoropyridine

In this present work, to investigate the physicochemical properties of the molecules, extensive quantum chemical calculations have been performed on 2-cyano-5-fluoropyridine (2C5FP) and 3-cyano-2-fluoropyridine (3C2FP). Infrared and Raman spectra analysis have been carried out to study the vibrational modes of the molecule. Based on density function theory (DFT) with 6–311 ++ G (d, p) basis set, was also used to compute the same modes. As a result of intramolecular interactions, charge transfer or delocalization of charge has been explained by natural bond orbital analysis. The NMR study was also carried out experimentally and theoretically. The nucleophilic and electrophilic sites were predicted by Molecular Electrostatic Potential surface (MEP). By using the same functional and basis set and GIAO method, theoretical predictions were made. The absorption wavelengths of title molecules have been studied both theoretically and experimentally using UV–visible analysis. The Mullikan population analysis and Natural atomic charges are used to calculate the net charges of the atoms in the molecules, and the calculated net charges are compared to the experimental chemical shift values. A molecular docking study revealed that the title molecules may have antidiabetic properties when bound to protein Glycogen Phosphorylase B Complexed Glucose

Molecular structural analysis, conformers and spectral (FT-IR, FT-Raman, NMR and UV-Visible), Importance of solvent role in molecular, ADME and molecular docking investigation on alpha-cyano-4-hydroxycinnamic acid

The primary objective of research to reveals the effective drug treatment for corona virus disease (COVID-19). The current study on alpha-cyano-4-hydroxycinnamic acid (ACHC), the theoretical predictions were done by using Gaussian 09 W software on the basis of DFT/ TDFT/B3LYP methods with basis set of 6–311++G (d, p). The vibrational wavenumbers were obtained from the observed FT-IR and FT-Raman spectra and these vibrations were assigned on the basis of their potential energy distribution (PED) contribution. 1H and 13C NMR chemical shift of the molecule were computed by using Gauge independent atomic orbital (GIAO) method. In UV-Visible analysis the electronic transition was predicted by Time-dependent self-consistent field (TD-SCF)/DFT method. NBO analysis was done to understand the possible the intermolecular interaction, electron transition within the donor and acceptor orbitals of the molecule. The HOMO and LUMO indicates the prominent charge transfer possibilities and its energy gap shows stability of the molecule. A molecular electrostatic potential (MEP) image shows the electrophilic and nucleophilic sites of the molecule. Molecular docking analysis was carried out against Agaricus bisporus tyrosinase (2Y9X) and severe acute respiratory syndrome corona virus 2 (6LZG)

Vibrational spectra and quantum chemical investigations on nicotinium nitrate monohydrate single crystal for anti bacterial studies

Nicotinium Nitrate Monohydrate (NNM) was grown by slow evaporation method. The arrangment of the molecules and hydrogen bonding intractionsin the grown crystal were analyzed using single crystal XRD. The structure, functional groups (vibrational analysis) and electronic properties (Mulliken and HOMO-LUMO analysis) were calculated by the density functional theory (DFT)/B3LYP/wB97XD method using 6–311++G (d,p) basis set. Also, the binding energy and the effect of basis set superposition error (BSSE) on the ring motifs have been investigated. The intermolecular interactions and charge delocalization density of NNM crystal have been analyzed using NBO 3.1 program. The strength of intermolecular interaction was further analyzed by 3D Hirshfeld surface analysis using fingerprint plot. Improved solubility of the title crystal NNM shows an enhanced physio-chemical activity compared to pure vitamin B3 (Nicotinic acid). The antibacterial activity of NNM crystal increased against Staphylococcus aureus a gram-positive bacteria when compared with pure nicotinic acid

Synthesis and spectroscopic characterization on 4-(2,5-di-2-thienyl-1H-pyrrol-1-yl) benzoic acid: A DFT approach

WOS: 000365367100002PubMed ID: 26186392A complete structural and vibrational analysis of the 4-(2,5-di-2-thienyl-1H-pyrrol-1-yl) benzoic acid (TPBA), was carried out by ab initio calculations, at the density functional theory (DFT) method. Molecular geometry, vibrational wavenumbers and gauge including atomic orbital (CIAO) C-13 NMR and H-1 NMR chemical shift values of (TPBA), in the ground state have been calculated by using ab initio density functional theory (DFT/B3LYP) method with 6-311G(d,p) as basis set for the first time. Comparison of the observed fundamental vibrational modes of (TPBA) and calculated results by DFT/B3LYP method indicates that B3LYP level of theory giving yield good results for quantum chemical studies. Vibrational wavenumbers obtained by the DFT/B3LYP method are in good agreement with the experimental data. The study was complemented with a natural bond orbital (NBO) analysis, to evaluate the significance of hyperconjugative interactions and electrostatic effects on such molecular structure. By using TD-DFF method, electronic absorption spectra of the title compound have been predicted and a good agreement with the TD-DFF method and the experimental one is determined. In addition, the molecular electrostatic potential (MEP), frontier molecular orbitals analysis and thermodynamic properties of TPBA were investigated using theoretical calculations. (C) 2015 Elsevier B.V. All rights reserved