Magnetic and spectroscopic behaviour of copper(II) complexes of 5-substituted 2-salicylidenebiguanides

Abstract

Copper(II) complexes of 2-salicylidenebiguanide (salbg) and its 5-substituted derivatives R-salbg (R = Me, Et, Ph, or 2Et) have been studied by magnetic and spectroscopic methods. The magnetic moments and magnetic-susceptibility values over the range 80–310 K indicate antiferromagnetic interaction in these complexes. Attempts have been made to fit the data to models suggested for polynuclear CuII complexes. The analysis reveals that the degree and nature of polymerisation vary with substitution on the biguanide moiety. With increase in size of the substituent, the complexes change from a trimeric to a dimeric form. Higher ligand-fieid band positions in the electronic spectra of the complexes indicate a distorted square-planar structure. The i.r. spectra suggest phenoxide bridging.