Synthesis, characterization, thermal and DFT studies of S-methyl-β-N(3-(2-nitrophenyl)allylidene)dithiocarbazate as anti-bacterial agent

S-Methyl-beta-N-(3-(2-nitrophenyl)allylidene)dithiocarbazate (HL), Schiff base of S-methyl dithiocarbazate, was synthesized by 1:1 condensation between S-methyl dithiocarbazate and trans-o-nitro cinna-maldehyde. It's in-vitro cytotoxicity is assayed against two habitually infection causing bacteria strains including gram-positive Staphylococcus aureus and gram-negative Escherichia coli for antibacterial activity. The results showed appreciable biological activity and the activity increased with increase in concentration. This nitrogen-sulfur based Schiff base (HL) was characterized by Mass, FT-IR, H-1-NMR, C-13 NMR, Raman, and UV-Vis spectroscopic techniques. Theoretical quantum chemical calculation has been performed using DFT in combination with B3LYP exchange correlation functional and 6-311++ G (d, p) basis sets level. The computed parameters were: Chemical potential of compound (mu) -0.174 eV, HOMO-LUMO energy gap -0.11093 eV, chemical hardness (eta) -0.055 eV, softness (S) 2.164 eV, ionization energy (IE) -0.23026 eV, electron affinity (EA) -0.11933 eV, the electronegativity (EN) 0.174 eV, dipole moment (D) 1.3383 Debye and relative stabilization energy -1536.982 eV. In the theoretical FT-IR spectrum analysis 81 fundamental vibrational modes has be observed because of non-linear structure of HL with potential energy distribution percentage (PED%) by using VEDA-4 package. Theoretically calculated parameters like H-1-NMR, C-13 NMR, FT-IR, UV-VIS, Raman, electrostatic potential and HOMO-LUMO energy gap were in conformity with experimental results. Thermal reactivity of the ligand was studied by TGA decomposes completely to give gaseous products. (C) 2018 Elsevier B.V. All rights reserved.