FTIR, FT-Raman, FT-NMR and quantum chemical investigations of 3-acetylcoumarin.

3-Acetylcoumarin (3AC) was synthesised by a Knoevenagel reaction. Conformational analysis using the B3LYP method was also carried out to determine the most stable conformation of the compound. FTIR and FT-Raman spectra of 3AC have been recorded in the range 4000-400 and 4000-100 cm(-1), respectively.

FTIR, FT-Raman, FT-NMR, UV-visible and quantum chemical investigations of 2-amino-4-methylbenzothiazole.

The FT-IR (4000-400 cm(-1)) and FT-Raman (4000-100 cm(-1)) spectral measurements and complete assignments of the observed spectra of 2-amino-4-methylbenzothiazole (2A4MBT) have been proposed. Ab initio and DFT calculations have been performed and the structural parameters of the compound were determined from the optimised geometry with 6-31G(d,p), 6-311++G(d,p) and cc-pVDZ basis sets and giving energies, harmonic vibrational frequencies, depolarisation ratios, IR intensities and Raman activities. (1)H and (13)C NMR spectra were recorded and (1)H and (13)C nuclear magnetic resonance chemical shifts of the molecule were calculated using the gauge independent atomic orbital (GIAO) method.

Experimental, quantum chemical and natural bond orbital investigations of N-(2,4-dimethylphenyl)-2,2-dichloroacetamide and N-(3,5-dimethylphenyl)-2,2-dichloroacetamide.

N-(2,4-Dimethylphenyl)-2,2-dichloroacetamide (24DMPA) and N-(3,5-dimethylphenyl)-2,2-dichloroacetamide (35DMPA) of the configuration X(y)C(6)H(5-y)NHCO-CHCl(2) (where, X=CH(3) and y=2) were synthesised and an extensive spectroscopic investigations have been carried out. The ab initio and DFT studies were carried out with 6-31G** and cc-pVDZ basis sets to determine the structural, thermodynamical and vibrational characteristics of the compounds and also to understand the steric influence of methyl groups on the characteristic frequencies of amide (-CONH-) group. The most stable conformer has been determined by PES scan.

Spectroscopic, electronic structure and natural bond orbital analysis of o-fluoronitrobenzene and p-fluoronitrobenzene: a comparative study.

Experimental FTIR, FT-Raman and FT-NMR spectroscopic studies of o-fluoronitrobenzene and p-fluoronitrobenzene have been carried out. A detailed quantum chemical calculations have been performed using DFT/B3LYP method with 6-311++G** and 6-31G** basis sets. Complete vibrational analyses of the compounds were performed.