2,5-Diaryl-1,3,4-selenadiazo-les prepared from Woollins reagent

Abstract

Two polymorphs of 2,5-diphenyl-1,3,4-selenadiazole, C14H 10N2Se, denoted (Ia) and (Ib), and a new polymorph of 2,5-bis-(thio-phen-2-yl)-1,3,4-selenadiazole, C10H6N 2S2Se, (IIb), form on crystallization of the compounds, prepared using Woollins reagent (2,4-diphenyl-1,3-diselenadiphosphetane 2,4-diselenide). These compounds, along with 2-(4-chloro-phen-yl)-5-phenyl-1,3, 4-selenadiazole, C14H9ClN2Se, (III), and 2-(furan-2-yl)-5-(p-tol-yl)- 1,3,4-selenadiazole, C13H10N2OSe, (IV), show similar inter-molecular inter-actions, with π-π stacking, C - H⋯π inter-actions and weak hydrogen bonds typically giving rise to mol-ecular chains. However, the combination of inter-actions differs in each case, giving rise to different packing arrangements. In polymorph (Ib), the mol-ecule lies across a crystallographic twofold rotation axis, and (IV) has two independent mol-ecules in the asymmetric unit. © 2011 International Union of Crystallography.