Abstract
Complexes of the type [M(pash)Cl] and [M(Hpash)(H2O)SO4] (M=Mn(II), Co(II), Ni(II), Cu(II) and Zn(II); Hpash = p-amino acetophenone salicyloyl hydrazone) have been synthesized and characterized by elemental analyses, molar electrical conductance, magnetic moments, electronic, ESR and IR spectra, thermal studies and X-ray powder diffraction. All the complexes are insoluble in common organic solvents and are non-electrolytes. The magnetic moment values and electronic spectra indicate a square-planar geometry for Co(II), Ni(II) and Cu(II) chloride complexes and spin-free octahedral geometry for the sulfato complexes. The ligand coordinates through >C=N–,–NH2 and a deprotonated enolate group in all the chloro complexes, and through >C=N–, >C=O and–NH2 in the sulfato complexes. Thermal analyses (TGA and DTA) of [Cu(pash)Cl] show a multi-step exothermic decomposition pattern. ESR spectral parameters of Cu(II) complexes in solid state at room temperature suggest the presence of the unpaired electron in d x 2 − y 2 . X-ray powder diffraction parameters for [Cu(pash)Cl] and [Ni(Hpash)(H2O)SO4] correspond to tetragonal and orthorhombic crystal lattices, respectively. The complexes show a fair degree of antifungal activity against Aspergillus sp., Stemphylium sp. and Trichoderma sp. and moderate antibacterial activity against E. coli and Clostridium sp.
Acknowledgements
The authors thank the Head, Department of Chemistry, Indian Institute of Technology, Kanpur for recording UV–Vis, IR and ESR spectra, and Dr. Nand Lal, Department of Life Sciences, C. S. J. M. University, Kanpur for help in biological screening.