Coordination diversity of new mononucleating hydrazone in 3d metal complexes: synthesis, characterization and structural studies

Abstract

The mononucleating hydrazone ligand LH3, a condensation product of salicyloylhydrazine and (2-formylphenoxy)acetic acid, was synthesized and its coordination behavior with first row transition metal(II) ions was investigated by isolating and elucidating the structure of the complexes using elemental analysis, conductivity and magnetic susceptibility measurements, as well as IR, 1H-NMR, electronic and EPR spectral techniques. The ligand forms mononuclear metal(II) complexes of the type [CoLH(H 2O)2], [NiLH(H 2O)2], [CuLH] and [ZnLH]. The ligand field parameters, Dq, B and ? values, in the case of the cobalt and nickel complexes support not only the octahedral geometry around the metal ion, but also imply the covalent nature of the bonding in the complexes. The EPR study revealed the presence of a spin exchange interaction in the solid copper complex and the covalent nature of the bonding. The 1H-NMR study of the zinc(II) complex indicated the non-involvement of the COOH group in the coordination. The physico-chemical study supports for the presence of octahedral geometry around cobalt(II), nickel(II) and tetrahedral geometry around copper(II) and zinc(II) ions. .