Exchange interactions in a one-dimensional bromo-bridged copper(II) compound with a ladder-like structure

Abstract

A deep green complex, [Cu(L)(μ-Br)Br]₂ (L = 1,4-diazacycloheptane) was synthesized and its crystal structure and magnetic properties have been studied. The structure determination reveals that in the binuclear unit each copper(II) occupies a distorted square pyramidal geometry in which each bridging bromine atom is simultaneously ligated in axial and equatorial positions between two adjacent copper(II) centres. The binuclear units are packed along the [101] direction. Each dimer is connected to its two nearest neighbours by two Cu–(μ-Br)⋯H–N–Cu hydrogen bonding interactions resulting in an infinite 1D ladder-like chain. The magnetic data were fitted considering the interdimer interactions using different models to obtain precise results and the susceptibility vs. temperature curve for the complex exhibits a maximum at 12 K indicating antiferromagnetic behaviour. Magneto-structural correlations have also been carried out.