Studies on the coordination of Cu(II) with o-droxyacetophenone-phenylhydrazones

Abstract

Complexes of <em>o</em>-hydroxyacetophenone-phenylhydrazone (OHAPH) and its methyl and chloro derivatives with Cutll) ion have been isolated. The complexes have been characterised on the basis of magnetic susceptibility and IR and ESR spectral measurements. ESR spectra reveal superhyperfine splitting, characteristic of the coordinated nitrogen of C =N bond. The bonding parameters <em>ɑ</em> and <em>β</em><em>, </em>though approximate, indicate in-plane and out-of-plane <em>π</em>-bonding which stabilises the square-planar stereochemistry of the complexes. The solution stability constants of the metal chelates obtained from the potentiometric study provide supporting evidence for (i) intermolecular H-bonding between the phenolic oxygen and the nitrogen of the secondary amino group, and (ii) back donation from metal to ligand through <em>π</em>-bonding.