Synthesis, characterization and antimicrobial activity of some nickel, cadmium and mercury complexes of 5-methyl-3yl-N-(2′-methylthiophenyl)-methyleneimine, (MP_zOATA) ligand

Abstract Herein, we report the syntheses and structures of Ni(II) complexes, [Ni(MP_zOATA)₂] (Cl) (PF₆) (I), [Ni(MP_zOATA)₂](ClO₄)₂.CH₃CN (II) & [Ni(MP_zOATA)₂](BF₄)₂.H₂O (III); Cd(II) complex, [Cd(MP_zOATA)Cl₂]₂ (IV) and a Hg(II) complex, [Hg(MP_zOATA)Cl₂] (V), of a pyrazole based ‘NNS’ donor ligand, 5-methylpyrazole-3yl-N-(2′-methylthiophenyl)methyleneimine, (MP_zOATA). The complexes are characterized byelemental analyses,electronic, IR, ¹H NMR (only for IV & V) spectral parameters, conductivity and fluorescence measurements. X-ray crystallographic data of the complexes reveal that the Ni(II) complexes have NiN₄S₂ octahedral coordination, one of them is a mixed-anion complex having Cl⁻ and PF₆⁻ as counter anions; the Cd(II) complex is a chloro bridged binuclear complex with octahedral coordinationenvironment aroundeach metal centre, while the Hg(II) complex is a square pyramidal one. Among the reported complex species, the Ni(II) complexes are non-fluorescent, while the Cd(II) and Hg(II) complexes can be used as potential photoactive materials as indicated from their characteristicemission properties. The reported complexes are screened for their antimicrobial activities against some Gram positive and Gram negative microbial strains, and they are found to be potential antimicrobial agents in broad spectrum against both Gram positive and Gram negative bacteria.