5,6-Dihydro-1,4-dithiine-2,3-dicarboxylic anhydride

Abstract

In the title compound (systematic name: 2,3-dihydro-1,4-dithiino[2,3-c]furan-5,7-dione), C6H4O3S2, the observed geometry agrees well with those of its phthalamide, thieno and hydroxy analogs, and with a calculated geometry obtained by density functional theory (DFT) calculations. Specific structural features are an S—C—C—S torsion angle of −70.39 (17)° and S—C bonds to sp 2-hybridized C atoms approximately 0.1 Å shorter than those to sp 3-hybridized C atoms. Unlike the extended structures of the analogs, there are no directed intermolecular interactions and the head-to-tail rows of molecules that are a prominent structural motif of the packing can be rationalized in terms of optimized dipole–dipole interactions.