om049025n_si_001.cif (135.09 kB)

Reactivity of the Unsaturated Complex [(C6Me6)2Ru22-H)3]+ toward Phosphines:  Synthesis and Molecular Structure of the Dinuclear Cations [(C6Me6)2Ru22-PR2)(μ2-H)2]+ and Characterization of the P−C Bond Activation Intermediate [(C6Me6)2Ru22-PPh2)(μ2-H)(μ2-Ph)]+

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posted on 11.04.2005, 00:00 by Mathieu J.-L. Tschan, Frédéric Chérioux, Lydia Karmazin-Brelot, Georg Süss-Fink
The unsaturated trihydrido complex [(C6Me6)2Ru22-H)3]+ reacts with diaryl- or dialkylphosphines PR2H to give the dinuclear cations [(C6Me6)2Ru22-PR2)(μ2-H)2]+ (R= Ph, 1; R = t-Bu, 2). Surprisingly, complexes of the type [(C6Me6)2Ru22-PR2)(μ2-H)2]+ with R = Ph (1), n-Bu (3), n-Oct (4) are also accessible in high yield from the reaction of [(C6Me6)2Ru22-H)3]+ with the corresponding triaryl- or trialkylphosphine PPh3, P(n-Bu)3, or P(n-Oct)3 by carbon−phosphorus bond cleavage. A possible intermediate of the reaction with PPh3, [(C6Me6)2Ru22-PPh2)(μ2-H)(μ2-Ph)]+ (5), could be isolated from the reaction mixture as the tetrafluoroborate salt, the single-crystal X-ray structure analysis of which reveals a bridging phenyl ligand coordinated in an η12 fashion to the diruthenium backbone. With the mixed phosphine PMe2Ph, [(C6Me6)2Ru22-H)3]+ reacts to give [(C6Me6)2Ru22-PMe2)(μ2-H)2]+ (6) and the corresponding intermediate [(C6Me6)2Ru22-PMe2)(μ2-H)(μ2-Ph)]+ (7). All dinuclear cations are isolated as the tetrafluoroborate salts.