Crystal structures of 2,4,6-triiodobenzonitrile and 2,4,6-triiodophenyl isocyanide

Abstract

The title crystals, C7H2I3N, are isomorphous. Both molecules lie across two crystallographic mirror planes and a twofold axis. The principal supramolecular interaction is centric R 2 2(10) CN/NC...I short contacts involving both ortho I atoms, with two contacts bisecting each cyano and isocyano group. These form ribbons along [010] and give rise to a planar sheet structure parallel to (100). All pairs of adjacent sheets have centric stacking, a mode not previously reported for sheets of this type. This study completes the series of homo-2,4,6-trihalobenzonitriles, in which I atoms give the strongest CN...X and NC...X interactions (X = F, Cl, Br, I).