Rare-earth-metal half-sandwich complexes incorporating methyl, methylidene, and hydrido ligands.

Complexes Cp*3Ln3(μ2-CH3)3(μ3-CH2)(μ3-H)(thf)3 (Ln = Y, Dy; Cp* = C5Me5) are formed via elimination of CH4 and C2H4 from the respective trinuclear polymethyl complexes [Cp*Ln(μ2-CH3)2]3, involving the methyl/methylidene complex Cp*3Ln3(μ2-CH3)3(μ3-CH2)(μ3-CH3)(thf)2 as an intermediate. Compound Cp*3Y3(μ2-CH3)3(μ3-CH2)(μ3-H)(thf)3 displays "Schrock-type" nucleophilic carbene reactivity, converting ketones into the corresponding terminal alkenes. Treatment of Cp*3Y3(μ2-CH3)3(μ3-CH2)(μ3-H)(thf)3 with [D4]methanol proved accessibility of all small-group functionalities as indicated by the simultaneous formation of deuterated HD and deuterated methanes CH3D and CH2D2.