Synthesis, characterization and biocidal activity of some transition metal(II) complexes with isatin salicylaldehyde acyldihydrazones

Abstract

Cobalt(II), nickel(II), copper(II), zinc(II) and cadmium(II) complexes with two new unsymmetrical ligands, isatin salicylaldehyde oxalic acid dihydrazide (isodh) and isatin salicylaldehyde malonic acid dihydrazide (ismdh) were synthesized and characterized by elemental analyses, electrical conductance, magnetic moments, electronic, NMR, ESR and IR spectral studies. The isodh acts as a dibasic tetra dentate ligand bonding through two >C=N-, a deprotonated phenolate and deprotonated indole enolate groups to the metal. The ismdh ligand shows monobasic tetra dentate behaviour in bonding with metal ion through two >C=N-, indole >C=O and a deprotonated phenolate group. The electronic spectral data suggest 4-coordinate square planar geometry for Co(II), Ni(II) and Cu(II) complexes of isodh, whereas, 6-coordinate octahedral structure for the ismdh complexes. The ESR studies also indicate a square planar and distorted octahedral environment around Cu(II) for isodh and ismdh complexes, respectively. Most of the metal complexes show better antifungal activity than the standard and a significant antibacterial activity against various fungi and bacteria.

Keywords::

• Transition metal complexes
• isatin salicylaldehyde acyldihydrazones
• NMR and IR spectral studies
• ESR spectra
• bioactivity

Acknowledgments

The authors thank the Head, S.A.I.F., Indian Institute of Technology, Mumbai, for recording ESR spectra, Prof. Nand Lal, Department of Life Sciences, CSJM University, Kanpur, for the help in biological screening.

Declaration of interest

The authors V.P.S and D.P.S. are grateful to UGC, New Delhi, and CSIR, New Delhi, respectively, for financial assistance.