Dinuclear rhodium complexes containing a linear C2RhC4RhC2 chain

Article abstract of DOI:10.1021/om9710780

The reaction of trans-[RhCl(=C=CHPh)(PiPr₃)₂] (1) and trans-[RhCl(=C=CMe₂)(PiPr₃)₂] (3) with 50% aqueous NaOH, in the presence of TEBA, afforded the hydroxorhodium complexes trans-[Rh(OH)(=C=CRR′)(PiPr₃)₂] (2, 4) in good to excellent yield. Compound 2 (R = H, R′ = Ph) reacted with D₂O to give trans-[Rh(OD)(=C=CHPh)(PiPr₃)₂] (2-d) and with Br?nsted acids HX (X = CF₃CO₂, OPh, C≡CPh) to yield the corresponding derivatives trans-[Rh(X)(=C=CHPh)(PiPr₃)₂] (5-7), respectively. Treatment of 2 and 4 with Ph₃-SnC≡CC≡CSnPh₃ also led to the displacement of the hydroxo ligand and to the formation of the dinuclear complexes tran,trans-[{Rh(=C=CRR′)(PiPr₃)₂} ₂(μ-C₄)] (8, 9) in 75-80% yield. The X-ray crystal structure analysis of 9 revealed the presence of a linear 10-atom C=C=RhC≡CC≡CRh=C=C chain with the midpoint of the central C-C bond as a crystallographic center of symmetry.