Synthesis and spectral characterization of Zn(II) complex of S-benzyl-β-N-[3-(4-hydroxy-3-methoxy-phenylallylidene)]dithiocarbazate: An approach to antibacterial, thermal studies and DFT calculations

Abstract S-benzyl-β-N-[3-(4-hydroxy-3-methoxy-phenylallylidene)]dithiocarbazate (HL) formed novel complex Bis[S-benzyl-β-N-[3-(4-hydroxy-3-methoxy-phenylallylidene)]dithiocarbazate]zinc(II) having general formula [Zn(HL)2] with (ZnII)-acetate, elucidated by UV-Vis, FT-IR, Raman, 1H-NMR, 13C-NMR, Mass spectroscopy revealed that [Zn(HL)2] complex has distorted square planner geometry around the metal ion, satisfied by N2S2 fashion. Density functional calculations of [Zn(HL)2] in gas phase were performed by using DFT (RB3LYP) with LanL2DZ basis set. VEDA-4 (Vibrational energy distribution analysis) software was employed for theoretical FT-IR spectrum analysis which yielded 249 fundamental vibrational modes along with potential energy distribution percentage (PED%) showing non-linearity of [Zn(HL)2]. Theoretically calculated parameters like UV-VIS, FT-IR, 1H-NMR, 13C-NMR, Raman, HOMO-LUMO energy gap and electrostatic potential were in conformity with calculated results. In addition to this, along with thermal analysis up to 800 0C, bio-efficacy of the [Zn(HL)2] has been examined against the growth of bacterial strains namely gram-positive S. aureus and gram-negative E. coli to evaluate their anti-microbial potential.