[M(GaCp*)₄] (M = Pd, Pt) as Building Blocks for Dimeric Homoleptic Cluster Compounds of the Type [MPt(GaCp*)₅]

The monomeric homoleptic Pt(0) complex [Pt(GaCp*)4] (1) has been synthesized by reaction of [Pt(COD)2] with GaCp* in hexane. The monomeric homoleptic Pd(0) complexes [Pd(GaCp*)4] (2) and [Pd{InC(SiMe3)3}4] (3) are accessible by reaction of [Pd(tmeda)(CH3)2] with GaCp* and [InC(SiMe3)3], respectively. These reactions were shown to proceed via methyl group transfer from palladium to indium or gallium, respectively. Complexes 1 and 2 can be used as building blocks for the synthesis of dinuclear cluster compounds. Thus, reaction of [Pt(COD)2] with 1 or 2 and subsequent addition of GaCp* yields [Pt2(GaCp*)2(μ2-GaCp*)3] (4a) and [PtPd(GaCp*)(μ2-GaCp*)3] (5a). Intermediates of this dimerization reactions, i.e., [Pt2(GaCp*)(μ2-GaCp*)3(η2-COD)] (4b) and [PtPd(GaCp*)(μ2-GaCp*)3(η2-COD)] (5b), were isolated and characterized by means of variable-temperature NMR spectroscopy.