Insertion vs ligand exchange: Reactivity of distanna ansa half-sandwich complexes of molybdenum and tungsten toward isocyanide and phosphine complexes of nickel and palladium

摘要

Addition of [Ni(CNtBu)_4] or [Ni(PEt_3)_4] to the molybdenum and tungsten distanna ansa half-sandwich complexes [{κ~1-SntBu_2SntBu_2(η~5- C_5H_4)}M(CO)_3] (M = Mo, W) leads to carbonyl-isocyanide and carbonyl-phosphine exchange, respectively, resulting in enhanced reactivity toward chalcogen insertion in the case of the isocyanide compounds 8 and 9. Additionally, the first examples of oxidative addition of a half-sandwich ansa bridge toward zerovalent transition metals are presented by preparing the novel 1,3-distanna-2-pallada ansa half-sandwich complexes 17-20 by addition of [Pd(CNtBu)_2].