Synthesis characterization and antimicrobial activity studies of some transition metal complexes derived from 3-chloro-6-methoxy-N’-((2-thioxo- 1, 2-dihydroquinolin-3-yl) methylene)benzo[b]thiophene-2- carboxyhydrazide

A series of new coordination complexes of Fe(III), Co(II), Ni(II), and Zn(II), with a new Schiff base 3-chloro-6-methoxy- N'-((2-thioxo-1,2-dihydroquinolin-3-yl)methylene) benzo[b] thiophene-2-carboxyhydrazide have been synthesized and characterized by elemental analysis, UV-Visible, IR spectra, 1HNMR spectra, mass spectra, powder X-ray diffraction data, molar conductance, magnetic susceptibility and TGA. The new Schiff base has been synthesized by the reaction between 3-chloro-6-methoxy benzo[b]thiophene-2-carboxyhydrazide and 2-thioxo-1, 2-dihydroquinoline-3-carbaldehyde. The Schiff base behaves as tridentate ONS donor ligand and forms the complexes of the type ML2-stoichiometry in case of Fe(III), Co(II) and ML-stoichiometry in case of Ni(II), and Zn(II). The Fe(III), Co(II) and Ni(II) complexes have octahedral geometry, whereas Zn(II) complex exhibited square planar geometry. The ligand and its metal complexes have been screened for their antibacterial activity against Staphylococcus aureus and Pseudomonous aeruginosa, antifungal activity against Aspergillus niger and Aspergillus flavus by cup plate method respectively and antioxidant activity by free radical scavenging activity using 1, 1- diphenyl-2-picryl hydrazyl (DPPH), with standard compounds vitamin-C and vitamin-E and DNA cleavage activity.