The reaction of RuCl 2 (PPh 3 ) 3 with HSiMeCl 2 in hexanes at 65 °C produced the trihydridosilylruthenium complex RuH 3 (SiMeCl 2 )(PPh 3 ) 3 (1). In the 1 H{ 31 P} NMR spectrum of 1, the ruthenium hydrides were observed at -9.76 ppm as a singlet with 29 Si satellites (J SiH ) 39.7 Hz), indicating the presence of nonclassical Ru‚‚‚H‚‚‚Si interactions. These nonclassical interactions were confirmed by a single-crystal X-ray diffraction study of 1. The silyl and phosphine groups occupy a tetrahedral arrangement around ruthenium, with the hydrides capping the faces defined by the silyl and two phosphines groups. Complex 1 exhibited a short Ru-Si bond (2.2760(4) Å) with three normal Ru-H distances (ca. 1.6 Å) and three long Si‚‚‚H interactions (ca. 1.9 Å). The Ru-H and Si‚‚‚H distances are consistent with interligand hypervalent interaction (IHI) theory in which Ru-H electron density is donated to Si-halogen σ* orbitals, giving rise to Ru-H‚‚‚Si interactions. Differences between the three Si‚‚‚H separations in the solid state reflect the asymmetry in the substituent pattern at silicon and are further reinforced by the extent to which the hydride ligands (and one chloride substituent) engage in weak hydrogen bonds with the ortho hydrogens of the phenyl groups.

The reaction of RuCl2(PPh3)3 with HSiX3 in benzene produced (η6-benzene)Ru(PPh3)(SiX3)2 (SiX3 = SiCl3 (1), SiMeCl2 (2)) as white to light yellow solids in high yields (>80%). A mixture of (η6-benzene)Ru(PPh3)(SiMe2Cl)2 (3), (η6-benzene)Ru(PPh3)(SiMe2Cl)(SiMeCl2) (4), and 2, due to silicon substituent redistribution, was obtained from the reaction of RuCl2(PPh3)3 with HSiMe2Cl in benzene. (η6-benzene)Ru(PPh3)(SiMe3)2 (5) was prepared by the methylation of 1, 2, or the 3/4 mixture with AlMe3. The related complexes (η6-arene)Ru(PPh3)(SiMeCl2)2 (arene = toluene (6), o-xylene (7), m-xylene (8), p-xylene (9), mesitylene (10), anisole (11)) were obtained from the reaction of RuCl2(PPh3)3 with HSiMeCl2 in the corresponding arene solvent at elevated temperature. Complexes 1, 2, and 5 were structurally characterized by single-crystal X-ray diffraction and exhibit a characteristic three-legged “piano-stool” geometry. The Ru−Si distances, in these complexes, ranged from 2.322 to 2.438 Å; the Ru−Si distance increased as the number of methyl groups on silicon increased.

The title ruthenium complex was found to catalyze the hydrosilylation and/or dimerization of phenylacetylene in the presence of a variety of hydrosilanes. Chlorohydrosilanes (HSiMeC12, HSiMe2C1 and HSiC13) favored the formation of the corresponding Ysilylstyrenes while HSiEt3 favored the formation of 1,4-diphenylbuteneyne; Z-isomers were the major product regardless of the substituents on silicon.