Molecular complexes of some mono- and dicarboxylic acids with trans-1,4-dithiane-1,4-dioxide

Abstract

Crystallization of carboxylic acids with molecules containing complementary hydrogen bonding groups, e.g., 4,4'-bipyridine, phenazine, and 2-pyridone, is an active pursuit in crystal engineering. We describe in this paper an addition to this family of spacer ligands, trans-1,4-dithiane-1,4-dioxide 4, a molecule that forms complexes with carboxylic acids via O-H···O and C-H···O hydrogen bonds. Analysis of hydrogen bonding in the molecular complexes of 5-nitrosalicylic acid 6, 3,5-dinitrosalicylic acid 7, succinic acid 8, and oxalic acid 9 with disulfoxide 4 shows that these crystal structures are stabilized by acid-sulfoxide and sulfoxide-sulfoxide supramolecular synthons XII and XIII. The preference for acid-sulfoxide recognition in crystals is explained through database analysis and energy computation.