Recent Study on Synthesis, Characterization and Bioactivity Study of Bidentate NS Schiff Base of S-Benzyl Dithiocarbazate and its Zn (II) and Pd (II) Complexes

The bis-chelated four coordinate complexes (ML2, L = deprotonated ligand) of Zn(II) and Pd(II) ions synthesized, were derived from a new bidentate NS Schiff base called S-benzyl- -N-(4-hydroxy-3-nitrophenyl)methylene dithiocarbazate (HL), which is the condensation product of S-benzyl dithiocarbazate (SBDTC) with 4-hydroxy-3-nitrobenzaldehyde. The ligand and its complexes were characterised using standard techniques such as NMR, UV-visible, IR, mass spectroscopy, magnetic susceptibility measurement, and molar conductance. The proposed crystal structure of the ligand was confirmed by X-ray crystallography data from a single crystal. The ligand exists in its thione tautomeric form in both solid and solution phases. The chelates were created by reacting the metal ions with the azomethine nitrogen atom of the ligand and the deprotonated thiolate sulphur anion. Magnetic susceptibility and electronic spectroscopic data suggested that the ZnL2 complex had a tetrahedral geometry, whereas the PdL2 complex had a square planar structure. Tail flick and carrageenan induced paw edoema tests were used to assess the analgesic and anti-inflammatory activities of the ligand and its complexes. When compared to the control, the ligand at 10 mg/kg produced a significant (***p < 0.001) increase in pain threshold in tail flick methods, but it demonstrates moderate activity in complexes. When compared to the control, the ligand and complexes significantly reduced paw edoema (***p< 0.001). Overall, these findings indicate that the ligand and its complexes could be employed as an effective anti-inflammatory agent.