SYNTHESIS AND SPECTRAL STUDIES OF BINUCLEAR TRANSITION-METAL COMPLEXES OF DIAMIDEDIIMINE HEXAAZAMACROCYCLES

The template condensation of alkylacetoacetate with diethylenetriamine resulted in the formation of homodinuclear transition metal complexes of a 20-membered macrocyclic ligand. The overall geometry and the mode of bonding have been inferred from IR, H-1 NMR, EPR and electronic spectral studies as well as magnetic and molar conductance data. An octahedral geometry around the metal ion is suggested for [M2L1X2] and [M2L1'X2] where M = iron(II) and cobalt(II), and X = Cl or NO3. A distorted square planar and a tetrahedral geometry is proposed for [M2L2]X2 and [M2L2']X2 when M = copper(II) and zinc(II) respectively; X = Cl or NO3. The distortion in the copper complexes is confirmed through EPR investigation.