Some sulphur-nitrogen ring transformations using tetrasulphur tetranitride and trichlorotrithiatriazene as precursors

Abstract

As part of a general study of 1, 2, 3, 5-dithiadiazolium cations, a series of 4-phenyl-1, 2, 3, 5-dithiadiazolium salts were produced by anion exchange reactions, both in the solid phase and in solution. The reduction of the 4-phenyl -1, 2, 3, 5- dithiadiazoliurn cation gave the previously unreported, 4-phenyl- 1, 2-dithia-3, 5-diazole, the crystal structure of which indicates that the dithiadiazole exists as an eclipsed dimmer. By analogy with the solid phase exchange reactions which occur between 4-phenyl-1, 2, 3, 5-dithiadiazolium chloride and Group I metal halides, the metathetical reactions between s (_3) N (_2) Cl and metal halides were investigated. The product isolated from the reaction of s (_3) N(_2) Cl with CsI was identified as tetrasulphur tetranitride. The reductions of S (_4) N (_3) C1, S (_3) N (_2) C1 (_2) and (NSC1) (_3) were studied using a variety of reducing agents. The majority of the reduction reactions gave tetrasulphur tetranitride but the reduction of trichlorotrithiatriazene by iron using sulphur dioxide as a solvent provided a convenient synthesis of the cyclocyclopentathiapentazenium cation (S (_5) N (_5) +). The reduction of chlorothiodithiazyl chloride by iron using sulphur dioxide as a solvent produced the previously unreported salt (s (_10) N (_8) (^2) +) (FeC1 (_4) -) (_2). The synthesis of the cations S (_x) N (^+) (x>l) was approached from two angles, that of reacting sulphur polycations (s (_8) (^2+) (AsF (_6) (^-)) (_2)) with nitrogen containing species (MN (_3) and S (_4) N (_4) and that of reacting the thionitrosyl cation (NS (^+)) with sulphur. The reactions of s (_8) (^2) (^+) (AsF (_6) (^-)) (_2) with azides and tetrasulphur tetranitride led to the formation of the S (_2) N(^+) cation and with excess tetrasulphur tetranitride to the production of S (_10) N (_8) (^2) (^+) (AsF (_6) (^-)) (_2) Some preliminary investigative reactions of selenium (Se (_4) (^2) (^+) (AsF (_6) (^-)) (_2) and Se (_8) (^2) (^+) (AsF (_6) (^-)) (_2)) and tellurium (Te (_4) (^2) (^+) (AsF (_6) (^-)) (_2)) polycations with both azides and tetrasulphur tetranitride were carried out and a selenium analogue of "S (_3) N (_2) (^+)” isolated. In an attempt to prepare thiazyl fluoride (as a precursor to thionitrosyl salts) by a simple single stage process, chlorine monofluoride was reacted with S (_4) N (_4) and (NSCL) (_3) are discussed. NSF was synthesised by a metathersis reaction between thiazyl chloride and cesium fluoride. A facile route to the thionitrosyl cation via the oxidation of (NSCL) (_3) and S (_4) N (_4) using Group V Lewis acids (AsF (_5), SbF (_5)) at 100-150 C failed. However a convenient route to thionitrosyl hexachloroantimonate (v) has been found in the vapour phase reaction of thiazyl chloride with antimony pentachloride.