Synthesis, Spectral and Quantum-Chemical Calculations on 5-Bromo-4-hydroxy-3-methoxy-2-nitro Benzaldehyde Schiff Base of S-Benzyldithiocarbazate

A new Schiff base has been synthesized by the 1:1 condensation of 5-bromo-4-hydroxy-3-methoxy-2-nitro benzaldehyde and S-benzyldithiocarbazate. The structure of this Schiff base was determined by FT-IR and H-1 NMR and mass spectroscopic data. The synthesized Schiff base has been subjected to theoretical studies by using Semi-empirical AM1, PM3, MNDO and MNDO/d quantum-chemical methods. The vibration frequencies, HOMO-LUMO energy gap, molecular hardness (eta), ionization energy, electron affinity, total energy and dipole moment and molecular electrostatic potential surface were analyzed. The theoretically obtained results were found to be consistent with the experimental data reported. A good correlation has been observed between experimental and calculated values for vibration modes.