Reversible Oxidative Se−Se Coupling of Phosphine Selenides by Ph 3 Sb(OTf) 2

Salts of diphosphoniumdiselenide dications ([R 3 PSeSePR 3 ][OTf] 2 ) have been isolated from reactions of trialkylphosphine selenides with triphenylantimony bistriflate. The redox process is speculated to proceed via a cationic coordination complex [Ph 3 SbL 2 ][OTf] 2 (L=Me 3 PSe, i Pr 3 PSe), which is also formed in the reaction of [R 3 PSeSePR 3 ][OTf] 2 with Ph 3 Sb. The observations indicate that the reductive elimination of [R 3 PSeSePR 3 ] 2+ from [Ph 3 Sb(SePR 3 ) 2 ] 2+ is reversible through the oxidative addition of [R 3 PSeSePR 3 ] 2+ to Ph 3 Sb.