Halogenation of (phosphine chalcogenide)gold(I) halides; some unexpected products

The monoselenide of 1,8-bis(diphenylphosphino) naphthalene reacts with (tht)AuCl to give the gold(III) system [(dppnAuSe)(2)](2+) 2Cl(-) (1); bromination of the bromogold(I) complex of the 1,2-bis(diphenylphosphino) methane monosulfide ligand furnishes the tribromide salt (2a) of a gold(III) cation [LAuBr2](+); bromination of the bromogold(I) complex of the 1,2-bis(diphenylphosphino) benzene monosulfide ligand leads to a mixed bromide/tetrabromoaurate salt (3) of a heterocyclic dication involving a[-PPh2-S-PPh2-](2+) moiety; analogous reactions of triphenylphosphine sulfide and selenide complexes lead to tetrabromoaurate salts (4a and 4b) of the (bromochalcogeno)phosphonium cations Ph3PEBr+.