Preparative and spectroscopic studies of some sulphur halide species
Raman spectra of trichlorosulphonium tetrachloroaluminate, SCl3+ AlCl4, and hexachloroantimonate, SCl3+ SbCl6-, are in agreement with previously reported work. Two complexes of the noveltribromosulphonium cation, SBr3+ AlX4 (X = Cl, Br), have been prepared and Raman spectra assigned on the basis of a pyramidal, C3v, SBr3+ ion. Mixing solid trichloro-and tribromosulphonium tetrachloroaluminates produced a solid containing mixed chlorobromosulphonium cations, SClnBr3-n+ AlCl4- (O < n < 3). Reactions involving sulphurdichloride, bromine and aluminium trichloride orantimony pentachloride yielded solids whose Raman Spectraare assigned to mixtures of mixed chlorobromosulphoniumtetrachloroaluminates or hexachloroantimonates. No pure compounds involving the ions SCl2Br+ or SClBr2+ were isolated. The Raman spectrum of sulphur tetrachloride is substantially in agreement with recently published work and can be assigned reasonably on the basis of a structure involving SCl3+ and Cl- ions. However, there are differences from the selenium and tellurium analogues. Reaction of dimethyl sulphide with chlorine or bromine in the presence of a Lewis acid (aluminium trihalide, tin tetrahalide or antimony pentachloride) yielded a series of complexes of the dimethylhalo-sulphonium cation, (CH3)2SX+ (X=Cl, Br). Analogous complexes of the methyldihalosulphonium cation,CH3SX2+ (X = Cl, Br), were prepared from dimethyl disulphide. Reactions of antimony pentachloride in the presence of bromine yielded complexes of the pentachlorobromoantimonate anion, SbCl5Br-, in contrast to similar reactions involving sulphur dichloride. Raman spectra are assigned for the methylhalosulphonium ions. Reactions of dimethyl sulphide and bromine gave two isomeric complexes which, on the basis of the analytical and spectral evidence, were assigned as the charge-transfer species, (CH3)2SBr2, or an ionic complex (CH3)2SBr+Br-. Sulphur dichloride and bromine, sometimes in the presence of chlorine, yielded a series of solids stable only at low temperatures. Analysis of their Raman spectra suggested the presence of mixed chlorobromosulphonium cations associated with various halide or polyhalide anions.