Synthesis and characterization of Ni (II) complex with an asymmetrictridentate Schiff base ligand and investigation of biological activitiy

Schiff bases are flexible compounds that are easily synthesized from the condensation of an amino compound with carbonyl compounds and these interesting class of compounds having an azomethine linkage(C=N)[1]. Heterocyclic Schiff base ligands containing nitrogen, sulfur, and oxygen donor atoms, and their transition metal complexes are of great interest as simple structural models of the biological system due to the presence of multifunctional groups [2]. Schiff bases and their metal complexes have been shown to be promising leads for both synthetic and structural research due to their relatively simple synthesis and structural diversity and have been widely investigated, due to their incredible chemical properties and applications in various areas. Over the past few years, there have been many reports on their applications as homogeneous and heterogeneous catalysis and antibacterial, antifungal and antitumor activities[3,4].A new Ni(II) complex with 2-(2-hydroxy-3-methoxybenzylidene)hydrazine -1-carbothioamide (HL) in the presence of imidazole has been prepared (scheme 1). This complex was characterized by chemical analysis, 1H NMR, UV–Vis and FT-IR spectroscopy. The synthesized ligand and the metal complex were screened for their antibacterial activity against two-gram positive bacteria (Staphylococcus aureus and Bacillus subtilis) and two-gram negative bacteria (Escherichia coli and Klebsiella pneumonia). The results revealed that the metal complex has shown pronounced activity than the free ligand[5].