Insertion of Ethyne into the Ru−Si Bonds of Coordinatively Unsaturated Ruthenium Silyl Complexes. X-ray Crystal Structures of Ru(CHCHSiMe₂OEt)Cl(CO)₂(PPh₃)₂ and [Ru(CHCHSiMe₂OH)(CN-<i>p</i>-tolyl)(CO)(PPh₃)₂]ClO₄

Abstract

The five-coordinate silyl complexes Ru(SiR3)Cl(CO)(PPh3)2(R3 = Me3 (1a), Et3 (1b), Ph3 (1c), Me2Cl (1f)) are conveniently prepared through reaction of Ru(Ph)Cl(CO)(PPh3)2 with the appropriate silane, HSiR3. Reaction of the Si−Cl bond in 1f with ethanol or hydroxide gives the corresponding ethoxysilyl or hydroxysilyl products Ru(SiMe2X)Cl(CO)(PPh3)2 (X = OEt (1d), OH (1e)). Ethyne readily inserts into the Ru−Si bond of 1a−d, and the corresponding five-coordinate, silylalkenyl complexes Ru(CHCHSiR3)Cl(CO)(PPh3)2 (R3 = Me3 (2a), Et3 (2b), Ph3 (2c), Me2OEt (2d)) can be isolated in good yield. The complexes Ru(CHCHSiR3)Cl(CO)2(PPh3)2 (SiR3 = SiMe3 (3a), SiEt3 (3b), SiMe2OEt (3d)) result from carbonylation of 2a,b,d. An X-ray crystal structure determination of Ru(CHCHSiMe2OEt)Cl(CO)2(PPh3)2 (3d) has been obtained. Reaction of Ru(CHCHSiMe3)Cl(CO)(PPh3)2 (2a) with CN-p-tolyl or sodium acetate gives Ru(CHCHSiMe3)Cl(CO)(CN-p-tolyl)(PPh3)2 (4a) or Ru(CHCHSiMe3)(η2-O2CCH3)(CO)(PPh3)2 (5a), respectively. Insertion of ethyne into the Ru−Si bond of 1e results in the formation of the metallacyclic ring-containing complex, Ru(CHCHSiMe2OH)Cl(CO)(PPh3)2 (6e), in which the hydroxysilyl oxygen atom is coordinated to ruthenium. Reaction of 6e with AgClO4 gives [Ru(CHCHSiMe2OH)(CO)(NCMe)(PPh3)2]ClO4 (7e) and substitution of the labile acetonitrile in this compound with CO or CN-p-tolyl generates [Ru(CHCHSiMe2OH)(CO)2(PPh3)2]ClO4 (8e) or [Ru(CHCHSiMe2OH)(CO)(CN-p-tolyl)(PPh3)2]ClO4 (9e), respectively. The crystal structure of 9e has been determined. Deprotonation of 8e or 9e with KOH gives the neutral complexes Ru(CHCHSiMe2O)(CO)2(PPh3)2 (10e) or Ru(CHCHSiMe2O)(CO)(CN-p-tolyl)(PPh3)2 (11e), respectively. Complex 1b has been shown to catalyze the hydrosilylation of both ethyne and phenylethyne by HSiEt3.