Crystal structure of cyclic sulfin- and sulfonamides of the thiazine series: Conformation,intra- and intermolecular interactions

An X-ray crystallographic study of a new compound is performed and the structure of five sulfin- and sulfonamides of the thiazine series is discussed. The conformation of the thiazine ring in all structures (a distorted boat) is stabilized by the intramolecular interaction of the C-H…N type. The nitrogen atom of the thiazine ring has a pyramidal configuration. The geometry of isolated molecules is calculated at density functional theory level (PBE1PBE, 6-31G(d,p)) and compared to that observed in the crystals. In the crystal structures different packing motifs are implemented with the formation of supramolecular associates of different types due to classical hydrogen bonds such as N-H…O.