VIBRATIONAL SPECTROSCOPIC INVESTIGATION OF METHYL(5-[2-THIENYLCARBONYL]-1H-BENZIMIDAZOL-2-YL: A COMPARATIVE DENSITY FUNCTIONAL STUDY
O. Alver1, C. Parlak2, Kaya M. Fatih2, G. Dikmen1, L. Genc,1
1Anadolu University, EskiЕџehir, Turkey
2DumlupД± nar University, KГјtahya, Turkey
Keywords: nocodazole, vibrational spectra, TED, DFT, SQM
Abstract
FT-IR and Raman spectra of methyl(5-[2-thienylcarbonyl]-1H-benzimidazol-2-yl (nocodazole) are experimentally examined in the region of 4000-400 cm –1. The optimized geometric parameters, conformational equilibria, normal mode frequencies, and corresponding vibrational assignments of nocodazole (C14H11N3O3S) calculated by means of the B3LYP hybrid density functional theory (DFT) method using the 6-31++G(d,p) basis set. Vibrational assignments are made based on the total energy distribution (TED) and the thermodynamic functions, highest occupied and lowest unoccupied molecular orbitals (HOMO and LUMO) of nocodazole are calculated. Calculations are employed for four energetically possible conformers of nocodazole (N1, N2, N3 and N4) in the gas phase. A comparison between the experimental and theoretical results indicates that the B3LYP method is able to provide satisfactory results for predicting vibrational wavenumbers if calculated values are scaled properly and the structural parameters.
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