New copper(II) complexes of 2-hydroxyacetophenone N(4)-substituted thiosemicarbazones and polypyridyl co-ligands: structural, electrochemical and antimicrobial studies

• DOI: 10.1016/j.poly.2004.09.004
• Publication Date: 2004-10-15T11:21:27Z
• Authors: Rohith P. John; A. Sreekanth; V. Rajakannan; T.A. Ajith; M.R. Prathapachan...
• Keywords: 01 natural sciences; 0104 chemical sciences; 3. Good health

Abstract Seven new copper(II) complexes of 2-hydroxyacetophenone N(4)-substituted thiosemicarbazones (H2L) and bidentate polypyridyl compounds 2,2′-bipyridine and 1,10-phenanthroline (B) were prepared and characterized. The thiosemicarbazones bind to the metal as dianionic ONS donors (L2−) and yield compounds of the stochiometry [MLB]. The structure of the compound [Cu(L4)(2,2′-bipy)] (6) was investigated by single-crystal X-ray diffraction method. Spin Hamiltonian and bonding parameters of the compounds calculated from the EPR spectra suggest square pyramidal (SPY) structure for the compounds. The g values predict geometry of C4v symmetry with B1g ground state. The bonding parameters show significant in-plane π-bonding. The cyclic voltammetric study of the complexes shows irreversible redox peaks corresponding to Cu(II/I) couple and quasi-reversible redox peaks corresponding to copper(II/III) oxidation. The thiosemicarbazones and their copper complexes show significant growth inhibitory activity against bacteria Escherichia coli, Staphylococcus aureus, and fungi Candida albicans and Aspergillus flavus.