Crystal structures of 4-PhCOS-5-RS-1,2-dithiole-3-thione (R = Me and PhCH₂), 4,5-(MeS)₂-1,2-dithiole-3-thione and 3,4,5-(MeS)₃-1,2-dithiolium iodide

Abstract

The crystal structures of the neutral dmt compounds, 4,5-bis(methylthiolato)-1,2-dithiole-3-thione, (1), 4-benzoylthiolato-5-methylthiolato-1,2-dithiole-3-thione, (3) and 4-benzoylthiolato-5-benzylthiolato-1,2-dithiole-3-thione, (4), and the organic salt, 3,4,5-tris(methylthiolato)-1,2-dithiolium iodide (2) have been determined at 120 K. The packing of the molecules provides a variety of intermolecular, or interion, contacts. Notable features in 1 and 3 are the columns of overlapping dithiole rings. In both cases the columns are propagated in the direction of b and neighbouring rings are related to one another by the operation of crystallographic centres of symmetry. In 2 weak C–H · · · I (H · · · I = 3.0236 and 3.0166 Å) and C–H · · · S (H · · · S = 2.8660 Å) hydrogen-bonds, contacts with short I · · · S distances (3.433 and 3.370 Å) and a C–H · · · π contact, with the dithiole ring as acceptor (H · · · Cg = 2.946 Å), create zig-zag chains propagated in the direction of b which are further connected to form corrugated sheets parallel to (0 0 1) with methyl groups on their surfaces. Intermolecular O · · · S_thiole contacts much shorter than the sum of the contact radii (3.32 Å) of oxygen and sulphur are present in 3 and 4.The formation of 3 or 4 occurred regiospecifically from successive reactions of 4,5-bis(benzoylthiolato)-1,2-dithiole-3-thione with one equivalent of caesium hydroxide and RI (R = Me or PhCH₂).