Interaction of metal carbonyl hydrides with Lewis acids

Article abstract of DOI:10.1021/om00072a014

Recent studies on Lewis acid promoted CO migratory insertion to produce metal acyls prompted a comprehensive study of the interaction of metal carbonyl hydrides with molecular Lewis acids. Stable rnetal formyl formation was not achieved in this study, but insight was obtained into reactions that may compete with migratory insertion in metal carbonyl hydrides. The reactivity of metal carbonyl hydrides with strong Lewis acids is dominated by the basic character of the hydride ligand. Variable-temperature multinuclear NMR characterization of the low-temperature complex Mn(CO)₅-H-BCl₃ is presented. The susceptibility to electrophilic metal hydrogen bond cleavage increases with decreasing acidity of the hydride, Steric factors are also important as evidenced by the observation that H₃Re₃(CO)₁₂ is much more resistant to eiectrophilic attack than is HRe(CO)₅. Also discussed are reactions of Lewis acids with HCo(CO)₄, [PPN][HFe(CO)₄], [Ir(CO)₂(PPh₃)₂H₂][BPh₄], HMn(CO)₄PPh₃, CpMo(CO)₃H; and CpMo(CO)2(PPh3)H.