A surprising reaction of trimethylphosphane with the unsaturated diruthenium complex [(η6C6Me6)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 [(eta(6)-C6Me6)(2)Ru-2-(mu(2)-H)(3)](+) give phosphido-bridged diruthenium cations of the type [(eta(6)-C6Me6)(2)Ru-2-(mu(2)-PR2)(mu(2)-H)(2)](+), trimethylphosphane surprisingly yields the substitution product [(C6Me6)Ru-2(PMe3)(3)(mu(2)-H)(3)](+) (1), as well as the racemic intermediate [(eta(6)-C6Me6)(2)Ru-2(PMe3)(2)(mu(2)-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 H-1 NMR spectroscopy. Cation 1 reacts with p-bromothiophenol to give the complex [(eta(6)-C6Me6)(2)Ru-2(PMe3)3-{mu(2)-(p-Br-C6H4)-S}(mu(2)-H)(2)](+) (3), isolated as the tetrafluoroborate salt. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)