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Reactions of Ru 3 (CO) 10 (μ-dppf) ( 1 ) (dppf = 1,1′-bis(diphenylphosphino)ferrocene), Ru 3 (CO) 10 (μ-dppm) ( 2 ) (dppm = bis(diphenylphosphino)methane), and the orthometalated derivative Ru 3 (CO) 9 {μ 3 -PPhCH 2 PPh(C 6 H 4 )} ( 3 ) with silanes (Ph 3 SiH, Et 3 SiH, Ph 2 SiH 2 ) are reported. Treatment of 1 with Ph 3 SiH and Ph 2 SiH 2 at room temperature leads to facile Si–H bond activation to afford Ru 3 (CO) 9 (μ-dppf)(SiPh 3 )(μ-H) ( 4 ) (60% yield) and Ru 3 (CO) 9 (μ-dppf)(SiPh 2 H)(μ-H) ( 6 ) (53% yield), respectively. The reaction of 1 with Ph 3 SiH has been investigated by electronic structure calculations, and these data have facilitated the analysis of the potential energy surface leading to 4 . Compound 1 does not react with Et 3 SiH at room temperature but reacts at 68 °C to give Ru 3 (CO) 9 (μ-dppf)(SiEt 3 )(μ-H) ( 5 ) in 45% yield. Reaction of 2 with Ph 3 SiH at room temperature yields two new products: Ru 3 (CO) 9 (μ-dppm)(SiPh 3 )(μ-H) ( 7 ) in 40% yield and Ru 3 (CO) 6 (μ 3 -O)(μ-dppm)(SiPh 3 )(μ-H) 3 ( 8 ) in 15% yield. Interestingly, at room temperature compound 7 slowly reverts back to 2 in solution with decomposition and liberation of Ph 3 SiH. Complex 8 can also be prepared from the direct reaction between 7 and H 2 O. Similar reactions of 2 with Et 3 SiH and Ph 2 SiH 2 give only intractable materials. The orthometalated compound 3 does not react with Ph 3 SiH, Et 3 SiH and Ph 2 SiH 2 at room temperature but does react at 66 °C to give Ru 3 (μ-CO)(CO) 7 {μ 3 -PPhCH 2 PPh(C 6 H 4 )}(SiR 2 R 1 )(μ-H)]( 9 , R = R′ = Ph, 71% yield; 10 , R = R′ = Et, 60% yield; 11 , R = Ph, R′ = H, 66% yield) by activation of the Si–H bond. Compounds 4 and 8 – 11 have been structurally characterized. In 4 , both the dppf and the hydride bridge a common Ru–Ru vector, whereas NMR studies on 7 indicate that two ligands span different Ru–Ru edges. Compound 8 contains a face-capping oxo moiety, a terminally coordinated SiPh 3 ligand, and three bridging hydride ligands, whereas 9 – 11 represent simple oxidative addition products. In all of the compounds examined, the triruthenium framework retains its integrity and the silyl groups occupy equatorial sites. |
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