Synthesis, spectroscopic characterization and DFT calculations of novel Schiff base containing thiophene ring

Abstract

In this study, a new Schiff base derivative, 2-[(2-hydroxy-5-thiophen-2-yl-benzylidene)-amino]-6-methyl-benzoic acid (5), which has a thiophene ring and N, O donor groups, was successfully prepared by the condensation reaction of 2-hydroxy-5-(thiophen-2-yl)benzaldehyde (3) and 2-amino-6-methylbenzoic acid (4). The characterization of a Schiff base derivative (5) was performed by experimentally the UV-Vis., FTIR, H-1 and C-13 NMR spectroscopic methods and elemental analysis. Density Functional Theory (DFT/B3LYP/6-311+G(d, p)) calculations were used to examine the optimized molecular geometry, vibrational frequencies, H-1 and C-13 NMR chemical shifts, UV-Vis. spectroscopic parameters, HOMO-LUMO energies and molecular electrostatic potential (MEP) map of the compound (5) and the theoretical results were compared to the experimental data. In addition, the energetic behaviors such as the sum of electronic and thermal free energy (SETFE), atomic charges, dipole moment of the compound (5) in solvent media were investigated using the B3LYP method with the 6-311+G(d, p) basis set. The obtained experimental and theoretical results were found to be compatible with each other and they were supported the proposed molecular structure for the synthesized Schiff base derivative (5)