Antimicrobial studies of the Zn(II) complex of S-benzyl-β-(N-2-methyl-3-phenylallylidene)dithiocarbazate

Antimicrobial resistance is a global concern with increases in multidrug-resistant bacteria. New coordination compounds could offer a solution. We report S-benzyl-beta-(N-2-methyl-3-phenylallylidene)dithiocarbazate (HL) forming bis[S-benzyl-beta-(N-2-methyl-3-phenylallylidene)dithiocarbazate]zinc(II), [Zn(L)(2)]; its bio-efficacy has been examined against the growth of gram-positive Staphylococcus aureus and gram-negative Escherichia coli to evaluate antimicrobial potential. The inhibition diameter results of E. coli and S. aureus were compared to standard drug (Erythromycin). Characterization by UV-vis, FT-IR, Raman, H-1 NMR, C-13 NMR, and mass spectroscopy revealed that [Zn(L)(2)] has distorted square planar geometry, coordinated through N-imine and S-thiolate. Density functional calculations of [Zn(L)(2)] in gas phase were performed by DFT (RB3LYP) with LanL2DZ basis set and the results are: chemical hardness (eta) 0.007915 eV, chemical potential (mu) 0.11643 eV, electron affinity (A) -0.10852 eV, softness (S) 7.855 eV, ionization energy (I) -0.12435 eV, electronegativity (chi) -0.11643 eV, dipole moment (D) 4.0690 Debye and with stabilization energy of -1718.1753 eV. Vibrational energy distribution analysis (VEDA)-4 software was employed for theoretical FT-IR spectrum, which yielded 237 fundamental vibrational modes. Theoretically calculated parameters like UV-vis, FT-IR, H-1 NMR, C-13 NMR, Raman, HOMO-LUMO energy gap and electrostatic potential were in conformity with experimental observations. The compound was docked with different receptors 1HT0, 1U3T, 1U3V, and 3S7S to find the best ligand-protein interactions.