Reactions of phosphine with carbonylbis(triethylphosphine)-rhodium(I) halides and derivatives

Abstract

The complex trans-[Rh(CO)X(PEt₃)₂]1(X = Cl, Br, I or NCS) reacts with PH₃ in dichloromethane at 183 K to give [Rh(CO)(PH₃)₂(PEt₃)₂]⁺2 which in turn reacts with CO in dichloromethane at 213 K to give [Rh(CO)₂(PH₃)(PEt₃)₂]⁺. The complex [Rh(CO)Cl₂H(PEt₃)₂], formed by reaction of 1 and HCl, reacts with PH₃ in dichloromethane at 219 K to give [Rh(CO)Cl(H)(PH₃)(PEt₃)₂]⁺; on warming, further displacement reactions with PH₃ give first [RhCl(H)(PH₃)₂(PEt₃)₂]⁺ and then the tris(phosphine) species [RhH(PH₃)₃(PEt₃)₂]²⁺. Enrichment with ¹³C in the carbonyl positions enabled the use of ¹³C NMR spectroscopy to investigate these reactions and the parameters of eleven rhodium complexes observed in this work are given.