A Surprising Reaction of Trimethylphosphane with the Unsaturated Diruthenium Complex [(η6-C6Me6)2Ru2 (μ2-H)3]+: Synthesis and Molecular Structure of the Cations [(η6-C6Me6)Ru2 (PMe3)3 (μ2-H)3]+ and [(η6-C6Me6)2Ru2 (PMe3)2(μ2-H)(H)2]+

Whereas aromatic or aliphatic phosphanes undergo cleavage of the P-C bond in the reaction with [(η6-C6Me6)2Ru2 (μ2-H)3]+ to give phosphido-bridged diruthenium cations of the type [(η6- C6Me6)2Ru2(2-PR2)(μ2-H)2]+, trimethylphosphane surprisingly yields the substitution product [(η6-C6Me6)Ru2 (PMe3)3 (μ2-H)3]+ (1), as well as the racemic intermediate [(η6-C6Me6)2Ru2(PMe3)2(μ2-H)(H)2]+ (2), in the form of the tetrafluoroborate salts. In complex 2, the hydrido ligands are fluxional in solution, as shown by variable-temperature 1H NMR spectroscopy. Cation 1 reacts with p-bromothiophenol to give the complex [(η6-C6Me6)2Ru2 (PMe3)3{μ2-(p-Br-C6H4)-S}(μ2-H)2]+ (3), isolated as the tetrafluoroborate salt.