Reactivity of Xantphos-Type Rhodium Complexes Towards SF 4 : SF 3 Versus SF 2 Complex Generation.

S-F-bond activation of sulfur tetrafluoride at [Rh(Cl)( tBu xanPOP)] (1; tBu xanPOP=9,9-dimethyl-4,5-bis-(di-tert-butylphosphino)-xanthene) led to the formation of the cationic complex [Rh(F)(Cl)(SF 2 )( tBu xanPOP)][SF 5 ] (2 a) together with trans-[Rh(Cl)(F) 2 ( tBu xanPOP)] (3) and cis-[Rh(Cl) 2 (F)( tBu xanPOP)] (4) which both could also be obtained by the reaction of SF 5 Cl with 1. In contrast to that, the conversion of SF 4 at the methyl complex [Rh(Me)( tBu xanPOP)] (5) gave the isolable and room-temperature stable cationic λ 4 -trifluorosulfanyl complex [Rh(Me)(SF 3 )( tBu xanPOP)][SF 5 ] (6). Treatment of 6 with the Lewis acids BF 3 or AsF 5 produced the dicationic difluorosulfanyl complex [Rh(Me)(SF 2 )( tBu xanPOP)][BF 4 ] 2 (8 a) or [Rh(Me)(SF 2 )( tBu xanPOP)][AsF 6 ] 2 (8 b), respectively. Refluorination of 8 a was possible with the use of dimethylamine giving [Rh(Me)(SF 3 )( tBu xanPOP)][BF 4 ] (9). A reaction of 6 with trichloroisocyanuric acid (TClCA) gave the fluorido complex [Rh(F)(Cl)(SF 2 )( tBu xanPOP)][Cl] (2 b) together with chloromethane and SF 5 Cl.