Selective Hydrogenation of Alkynes Catalyzed by Trinuclear Rhodium Hydride Complexes of the Type [{(Rh[PP*]H)₃(μ₂‐H)₃(μ₃‐H)}(BF₄)₂]

A clean win: A novel trinuclear rhodium(III)-hydride species allows for highly selective hydrogenation of diarylacetylenes under mild conditions (1 bar of hydrogen pressure at 30.0 °C in methanol) with low catalyst loadings (substrate/catalyst molar ratio≤10 000). In contrast to the mononuclear complex of the type [{Rh(PP*)(MeOH)2}BF4], no overhydrogenation of the diphenylacetylene to the alkane is observed. The hydrogen consumption follows Michaelis–Menten kinetics.