Vibrational spectroscopic analysis of 2, 3:4,5-Bis-O-(1-methylethylidene)beta-D-fructopyranose Sulfamate(Topiramate) by density functional method.

2,3:4,5-Bis-O-(1-methylethylidene)-beta-D- fructopyranose sulfamate otherwise called as Topiramate is a drug used for the treatment of alcohol dependence. Topiramate is a safe and consistently efficacious medication for treating alcohol dependence. The spectroscopic properties of Topiramate are investigated by Fourier Transform Infrared (FT-IR), Fourier Transform Raman (FT-Raman), Fourier Transform Nuclear magnetic Resonsnce(FT-NMR) andUltra Violet Visible (UV-visible) spectroscopic techniques.

The spectroscopic (FT-IR, FT-Raman), MESP, first order hyperpolarizability, NBO analysis, HOMO and LUMO analysis of 1,5-dimethyl napthalene by density functional method.

The Fourier-transform infrared and FT-Raman spectra of 1,5-Dimethyl Napthalene (15DMN) was recorded in the region 4000-400cm(-1) and 3500-50cm(-1) respectively. Quantum chemical calculations of energies, geometrical structure and vibrational wavenumbers of 6M2C were carried out by density functional theory (DFT/B3LYP) method with 6-311++G(d,p) basis set. The difference between the observed and scaled wavenumber values of most of the fundamentals is very small.

Spectroscopic and quantum chemical electronic structure investigations of 3,4-dihydrocoumarin and 3-methylcoumarin.

A complete vibrational analysis of 3,4-dihydrocoumarin and 3-methylcoumarin have been performed according to SQM force field method based on ab initio and DFT calculation 6-311++G(d,p) basis set and their frequencies are compared. The influences of carbon-oxygen bond and methyl group to the vibrational frequencies of the title compounds have been discussed. The pronounced decrease of the lone pair orbital occupancy and the molecular stabilization energy show the hyperconjugation interaction from the NBO analysis.

Structural conformations, tautomerization and vibrational spectral study of 6-amino-1-methylpurine with density functional theoretical calculations.

The FT-IR and FT-Raman spectra of 6-amino-1-methylpurine (AMP) have been recorded in the region 4000-400 cm(-1) and 3500-50 cm(-1) respectively. The optimized geometry, frequency and intensity of the vibrational bands of AMP have been obtained by DFT level of theory using B3LYP method with 6-311++G(d,p) basis set. A complete vibrational assignment aided by the theoretical harmonic frequency analysis has been proposed.

Conformational analysis, UV-VIS, MESP, NLO and NMR studies of 6-methoxy-1,2,3,4-tetrahydronaphthalene.

The detailed HF and B3LYP/6-311++G(d,p) comparative studies on the complete FT-IR and FT-Raman spectra of 6-methoxy-1,2,3,4-tetrahydronaphthalene [MTHN] have been studied. In view of the special properties and uses, the present investigation has been undertaken to provide a satisfactorily vibrational analysis of 6-methoxy-1,2,3,4-tetrahydronaphthalene. Therefore, a thorough Raman, IR, molecular electrostatic potential (MESP), non-linear optical (NLO) properties, UV-VIS, HOMO-LUMO and NMR spectroscopic investigation are reported complemented by B3LYP theoretical predictions with basis set 6-311++G(d,p) to provide novel insight on vibrational assignments and conformational stability of MTHN.

Density functional theory investigations on the conformational stability, molecular structure and vibrational spectra of 6-methyl-2-chromenone.

The Fourier-transform infrared and FT-Raman spectra of 6-methyl-2-chromenone (6M2C) was recorded in the region 4000-400 cm(-1) and 3500-50 cm(-1) respectively. Quantum chemical calculations of energies, geometrical structure and vibrational wavenumbers of 6M2C were carried out by density functional theory (DFT/B3LYP and LSDA) method with 6-311++G(d,p) basis set. The difference between the observed and scaled wavenumber values of most of the fundamentals is very small.

Quantum chemical studies on structure of 2-amino-5-nitropyrimidine.

FTIR and FT Raman spectra of 2-amino-5-nitropyrimidine (2A5NP) are recorded in the region 4000-400 cm(-1) and 3500-0 cm(-1), respectively. Molecular structure and vibrational frequencies of 2A5NP have been investigated by density functional theory (DFT) calculations using Becke's three parameter exchange functional combined with Lee-Yang-Parr correlation (B3LYP) and Hartree fock (HF) method employing 6-311++G(d,p) basis set. Calculations have been performed giving energies, optimized structure, harmonic vibrational frequencies, IR intensities and Raman activities.

Vibrational spectroscopic, first-order hyperpolarizability and HOMO, LUMO studies of 4-chloro-2-(trifluoromethyl) aniline based on DFT calculations.

The Fourier-transform infrared and FT-Raman spectra of 4-chloro-2-(trifluoromethyl) aniline (4C2TFA) were recorded in the region 4000-400 cm(-1) and 3500-50 cm(-1) respectively. Quantum chemical calculations of energies, geometrical structure and vibrational wavenumbers of 4C2TFA were carried out by density functional theory (DFT/B3LYP) method with 6-311+G(d,p) and 6-311++G(d,p) basis sets. The difference between the observed and scaled wavenumber values of most of the fundamentals is very small.