Probing magnetic exchange interactions in molecular magnets: an inclusion compound of a dithiadiazolyl radical

Abstract

Co-sublimation of the dithiadiazolyl radical, p-NCC ₆ H ₄ CNSSN 2 with the inclusion-forming host compound perhydrotriphenylene (PHTP) leads to trichroic crystals of the host-guest complex [PHTP-2]. Molecules of 2 are linked through a CN‥S interaction (ca. 3.03 Å) to form polar chains within the channels of the PHTP host lattice. The host-guest ratio is approximately 5:1. Pyroelectric and non-linear optic responses indicate that crystals of [PHTP-2] are macroscopically polar. A combination of variable temperature solid state EPR spectroscopy and magnetic susceptibility measurements are used to probe the electronic properties of [PHTP-2]; whilst [PHTP-2] is paramagnetic, no exchange coupling between neighbouring molecules of 2 within the channels could be established. The implications of these results on the magnetic exchange pathway of the weak ferromagnet, β-p-NCC ₆ F ₄ CNSSN β-1, are discussed.