Synthesis, spectral, redox and biological studies of some Schiff base copper(II), nickel(II), cobalt(II), manganese(II), zinc(II) and oxovanadium(II) complexes derived from 1-phenyl-2,3-dimethyl-4(4-iminopentan-2-one)pyrazol- 5-one and 2-aminophenol/2-aminothiophenol

Abstract

Neutral tetradentate complexes of Cu(II), Ni(II), Co(II), Mn(II), Zn(II) and VO(II) have been synthesised using new Schiff bases derived from 2-am inophenol/2-aminothiophenol and 1-phenyl-2,3-dimethy l-4(4-iminopentan-2-one)-pyrazol -5-one in ethanol and characterized by microanalytical data, IR, UV -Vis .. ¹H NMR and ESR spectra. Non-electrolytic behaviour and monomeric type of the chelates have been assessed from their 10Vl conductance and magnetic susceptibility values respectively. The IR and UV-Vis. spectra suggest that all the complexes have square planar geometry except vanadyl and manganese complexes which show square pyramidal and octahedral geometry respectively. The redox behaviour of copper and vanadyl complexes has been studied by cyclic voltammetry and the ESR spectra of copper and vanadyl complexes are recorded and discussed. Antimicrobial act ivity of the Schiff bases and their complexes have been extensively studied on some microorganisms like <i>Staphylococcus aureus, Bacillus subtilis, Klebsiella pneumoniae, Salmonella, typhi,</i> <i>Pseudomonous aeruginosa, Shigella flexneri, Aspergillus niger </i>and <i>Trichoderma viridi. </i>Most of the complexes have higher

activity than the free ligand.