Reactions of iridium and rhodium hydrides with anhydrous HF; crystal structure of [Rh(CO)(PPh3)3][BF4] · thf

Abstract The reactions of [MH(CO)(PPh 3 ) 3 ] (M = Rh or Ir) with anhydrous HF or HBF 4 · Et 2 O lead to completely different products. With an excess of acid, when M = Ir, oxidation gives [IrH 2 (CO)(PPh 3 ) 3 ][X](X = HF 2 , BF 4 ), whereas, when M = Rh, dissociation of a ligand and elimination of hydrogen gas gives a 1:1 mixture of [Rh(CO)(PPh 3 ) 2 (solv.)][X] and [HPPh 3 ][X] (X = HF 2 , BF 4 ). With a deficit of acid, [Rh(CO)(PPh 3 ) 3 ][X] is also generated which, for X = BF 4 , has been crystallographically characterised.