Ferromagnetic intermolecular exchange interaction in ethynyl-verdazyl radical crystals

Abstract

An oxoverdazyl radical substituted with p-ethynylphenyl has been synthesised and structurally characterized at different temperatures. Single-crystal XRD studies reveal that the radicals form unusual slipped 1D chains held together by π–π interactions. The intermolecular exchange interaction within the chain is ferromagnetic. This rare situation is tentatively related to the relative position of the radicals within the chains.