Concomitant polymorphs: structural studies on the trimorphic dithiadiazolyl radical, ClCNSSN

Abstract

The radical ClCNSSN (1) exhibits a rigid geometry which limits structural variation in the solid state to differences in packing motifs. Sublimation of 1 (75 °C, 10⁻² Torr) leads to the isolation of three distinct polymorphs; 1α (monoclinic, P2₁/n) crystallises as cisoid dimers with two molecules in the asymmetric unit, 1β (monoclinic, P2₁/c) crystallises as twisted dimers with four molecules in the asymmetric unit and 1γ (monoclinic, P2₁/c) crystallises as cisoid dimers (similar to 1α), but with eight molecules in the asymmetric unit. Despite their structural variations, all three structures exhibit similar structure-directing motifs based upon electrostatic S^δ+⋯N^δ− contacts.