Structure and magnetism of two new linear trinuclear copper(II) clusters obtained from the tetradentate N2O2 ligand bis(2-hydroxybenzyl)-1,3-diaminopropane

Reaction of bis(2-hydroxybenzyl)-1,3-diaminopropane (H2bhbd) with copper(II) perchlorate and copper(II) chloride in methanol, respectively, leads to linear trinuclear clusters, namely [Cu3(bhbd)2(CH3OH)2(ClO4)2] (1) and [Cu3(bhbd)2Cl2](CH3OH)4 (2). These coordination compounds were characterized by X-ray crystallography, UV–Vis, IR and EPR spectroscopy, and magnetic susceptibility measurements. Both complexes have a linear trinuclear array of copper ions bridged by means of phenolato O atoms and separated by a distance of 2.985(4) Å (1) and 2.937(4) Å (2). Strong antiferromagnetic interactions between these adjacent CuII ions govern the magnetochemistry of 1 (J = −303(1) cm−1) and 2 (J = −482(3) cm−1) resulting in S = 1/2 ground states fully populated below 150 K. A correlation between the interaction parameter J and the angles within the trinuclear clusters is proposed.