Theoretical Investigation of Nmr, Conformational, Vibrational and Electronic Structure of 3-Bromo-4-(2-Pyridyl) Thiophene

Abstract

Compoundscontaining thiophene and pyridine rings very much attention due to theirbiological activity. The molecular geometry, vibration frequencies, dipolemoment (μ), polarizability (α), hyperpolarizability (β) of3-Bromo-4-(2-pyridyl) thiophene have been calculated at ab initio Hartree Fock(HF) and Density Functional Theory (DFT / B3LYP) with 6-311++G (d, p) basisset. The highest occupied molecular orbital (HOMO), the lowest unoccupiedmolecular orbital (LUMO) of title molecule has been computed and theirrespective gap (ΔEg) have been examined. The gauge independent atomic orbital(GIAO) 1H- and 13C-NMR chemical shifts values of studiedmolecule in the ground state in both gas phase and in solution of chloroformand  dimethyl sulfoxide have beeninvestigated using the HF and DFT/B3LYP employing different basis sets. Inaddition, the potential energy curve of the molecule as a function of the dihedralangle (N-C3-C6-C7) have been carried out using the 6-31G basis set in bothmethods. The results of vibrational parameters were analyzed by VEDA 4software. The 1H chemical shifts values of the molecule, which were calculatedby both methods, were compared with the data in the literature and there was agood agreement between the structural parameters.