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(SiR 3 )Cl(CO)(PPh 3 ) 2 (R 3 = Me 3 ( 1a ), Et 3 ( 1b ), Ph 3 ( 1c ), Me 2 Cl ( 1f )) are conveniently prepared through reaction of Ru(Ph)Cl(CO)(PPh 3 ) 2 with the appropriate silane, HSiR 3 . Reaction of the Si−Cl bond in 1f with ethanol or hydroxide gives the corresponding ethoxysilyl or hydroxysilyl products Ru(SiMe 2 X)Cl(CO)(PPh 3 ) 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(CH CHSiR 3 )Cl(CO)(PPh 3 ) 2 (R 3 = Me 3 ( 2a ), Et 3 ( 2b ), Ph 3 ( 2c ), Me 2 OEt ( 2d )) can be isolated in good yield. The complexes Ru(CH CHSiR 3 )Cl(CO) 2 (PPh 3 ) 2 (SiR 3 = SiMe 3 ( 3a ), SiEt 3 ( 3b ), SiMe 2 OEt ( 3d )) result from carbonylation of 2a, b, d . An X-ray crystal structure determination of Ru(CH CHSiMe 2 OEt)Cl(CO) 2 (PPh 3 ) 2 ( 3d ) has been obtained. Reaction of Ru(CH CHSiMe 3 )Cl(CO)(PPh 3 ) 2 ( 2a ) with CN- p -tolyl or sodium acetate gives Ru(CH CHSiMe 3 )Cl(CO)(CN- p -tolyl)(PPh 3 ) 2 ( 4a ) or Ru(CH CHSiMe 3 )(η 2 -O 2 CCH 3 )(CO)(PPh 3 ) 2 ( 5a ), respectively. Insertion of ethyne into the Ru−Si bond of 1e results in the formation of the metallacyclic ring-containing complex, Ru(CH CHSiMe 2 OH)Cl(CO)(PPh 3 ) 2 ( 6e ), in which the hydroxysilyl oxygen atom is coordinated to ruthenium. Reaction of 6e with AgClO 4 gives [Ru(CH CHSiMe 2 OH)(CO)(NCMe)(PPh 3 ) 2 ]ClO 4 ( 7e ) and substitution of the labile acetonitrile in this compound with CO or CN- p -tolyl generates [Ru(CH CHSiMe 2 OH)(CO) 2 (PPh 3 ) 2 ]ClO 4 ( 8e ) or [Ru(CH CHSiMe 2 OH)(CO)(CN- p -tolyl)(PPh 3 ) 2 ]ClO 4 ( 9e ), respectively. The crystal structure of 9e has been determined. Deprotonation of 8e or 9e with KOH gives the neutral complexes Ru(CH CHSiMe 2 O)(CO) 2 (PPh 3 ) 2 ( 10e ) or Ru(CH CHSiMe 2 O)(CO)(CN- p -tolyl)(PPh 3 ) 2 ( 11e ), respectively. Complex 1b has been shown to catalyze the hydrosilylation of both ethyne and phenylethyne by HSiEt 3 .