Some reactions of dithianitronium hexafluroarsenate (v) with Mono-and multi-nitriles

Abstract

This work primarily concerns the compound dilmanitronium hexafluoroarsenate(V), [SNS]AsF(_6)], and its use in the synthesis of 1,3,2,4-dithiadiazolylium salts. Chapter one provides a short review of the dithianitronium cation, the physical and chemical properties of its salts and outlines various synthetic methods and reaction types. General details of experimental methodology are outlined in chapter two. The third chapter covers the reactions of [SNS]AsF(_6) with K[C(CN)(_3)], the first example of a reaction of the former species with a delocalised anionic system. Sequential reactions with one, two and three equivalents of [SNS][AsF(_6) gave (NC)(_2) .C=CNSNS (1), [(NC).C(CNSNS)(_2)][AsF(_6)] (2) and [C(CNSNS)(_3)][AsF(_6)](_2) (3), respectively. Compounds 1 and S were characterised by single crystal X-ray diffraction. Chapter four outlines the preparation of mixed 1,2,3,5- / 1,3,2,4- phenylene - bridged dithiadiazolyliums, in high yield, from [SNS][AsF(_6)] and [(NC).C(_6)H(_4).CNSSN][AsF(_6)]. Both the meta and para isomers were prepared, p-[NSNSC.C(_6)H(_4).CNSSN][AsF(_6)](_2).MeCN was characterised by single crystal X-ray diffraction, the magnetic and electronic properties of the radical cations and diradicals were studied. The radical cation salt, p- [NSNSC.C(_6)H(_4).CNSeN]C1 was shown to be a spin = V2 paramagnet. In the fifth chapter a similar methodology was applied in order to prepare and study the p-[NSNSC.C(_6)H(_4).CNSeSeN] dication and its corresponding diradical and radical cation. Preliminary magnetisation data indicate the latter chloride salt to be paramagnetic. The sixth chapter outlines the reaction of [SNS]AsF(_6)] with metal cyanides and rationalises the unexpected reaction with PhHgC=N, where a cationic linear thiazene, [PhSNSNSNSPh]+ (4), is formed. The hexafluoroarsenate(V) salt of 4 was characterised by single crystal X-ray diffraction. Thiazyl chloride, (NSCl)(_3), was utilised in the synthesis of the analogous compounds, [Ar(_2)S(_4)N(_3)]Cl (where Ar=o and p-(O(_2)N).C(_6)H(_4)), from the corresponding shorter, neutral, acyclic thiazenes (Ar(_2)S(_3)N(_2)).An attempt to prepare the first dithiadiazolylium fluoride is described in chapter 7. The unexpected product of the reaction of [p- Cl.C(_6)H(_4).CNSSN][AsF(_6)] with [Me(_4)N]F is the radical, [p-Cl.C(_6)H(_4).CNSSN], which was shown, by X-ray structure determination, to contain unusual S - N interactions which give rise to the formation of tetramers in the solid state.