Magnetostructural study of substituted α-nitronyl aminoxyl radicals with chlorine and hydroxy groups as crystalline design elements

Abstract

We present a new family of phenyl substituted α-nitronyl aminoxyl radicals which contain hydroxy- and chlorine-substituents as crystal engineering tools. The magnetic behaviour of these radicals strongly differs in dimensionality and strength, showing in all cases antiferromagnetic interactions. We have determined the X-ray crystal structure and analysed the crystal packings of these radicals. From this analysis all the observed magnetic properties can be conveniently rationalized by only considering the close contacts of NO groups of neighbouring molecules according to the generally accepted mechanisms for intermolecular magnetic interactions. Beside the strong O–H‥O(–N) hydrogen bonds and the weaker C–H‥O(–N) hydrogen bonds, weak Cl‥H bonds also seem to play a significant role in determining the molecular arrangement in the solid state and, therefore, the magnetic properties. In only one case are close Cl‥Cl contacts observed, pointing to attractive interactions between chlorine atoms.