Multi-functional magnetic materials based on dithiadiazolyl free radicals

The crystal structures of a series of dithiadiazolyl free radicals, p-XC6F4 CNSSN (X=F,Cl,Br and CN) are described in terms of dipolar interactions whi ch induce chain-like motifs in the solid state. When X=CN two morphologies are observed; the beta-phase is polar and undergoes a phase transition to a weakly ferromagnetic state at 36K, an unprecedented temperature for an org anic radical. The polar structure which gives rise to weak ferromagnetism i n beta-p-NCC6F4CNSSN, also provides a number of other potential solid state properties which may interact independently or cooperatively with the magn etic behaviour.