Novel benzildihydrazone based Schiff bases: Syntheses, characterization, thermal properties, theoretical DFT calculations and biological activity studies

Abstract

A novel series of benzildihydrazone derived Schiff base compounds having electron-accepting and donor-donating appendices were synthesized. A combined experimental and theoretical analysis was conducted to elucidate all the characteristic and structural features of the synthesized molecules. The experimental characterizations were performed by using FT-IR, H-1/C-13 NMR, mass spectroscopic techniques, and X-ray diffraction methods. The thermal stabilities of the molecules were evaluated by thermal gravimetric analysis (TGA) and all them were found to be stable above 300 degrees C. To support the experimental, structural, and spectroscopic data of the dyes, the quantum chemical parameters were obtained within the density functional theory (DFT) calculations. In addition, some properties based on the HOMO and LUMO energies and the temperature dependence of some thermodynamic quantities (i.e. entropy, heat capacity, and enthalpy) were also studied. According to the antimicrobial activity evaluation results, compound 1f has been found to be potentially effective in suppressing microbial growth of bacteria with variable potency. The DNA cleavage activity of the compounds was analysed by gel electrophoresis assay. The results showed that the compounds have DNA cleaving activity. (C) 2019 Elsevier B.V. All rights reserved.