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 Cu^II 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.