Synthesis, characterization, electrochemistry and axial ligation properties of macrocyclic divalent metal complexes of acetylacetone buckled with different diamines

Abstract

A series of macrocyclic nickel(II) copper(II) complexes using acetylacetone and different aliphatic and aromatic diamines (1,2-diamino ethane, 1,2-diamino propane, 1,2-diamino benzene, 1,3-diamino benzene and 3,4-diamino toluene) has been synthesized by the template method. These complexes were characterized by elemental analysis, conductivity measurements, electronic, infrared and NMR spectral data. The molar conductivity data show them to be non-electrolytes. The electronic spectral data in toluene (a non-coordinating solvent) suggest square planar geometry for these complexes. The axial coordination in these complexes is supported by their electronic spectra in dimethylformalide (DMF, a coordinating solvent). Various ESR parameters for all copper complexes have been calculated showing an axial d x 2− y 2 ground state. The electrochemical behaviour of these complexes has been studied by cyclic voltammetry.