Synthesis, reactivity and catalytic activity of [RuH(η1-OCMe2)(CO)2(PPri3)2]BF4

Abstract

The solvento complex [RuH(η1-OCMe2)(CO)2(PPri3)2]BF42, which is an active catalyst for the exclusive hydrogenation of phenylacetylene to styrene and the hydrosilylation of the same alkyne to cis-PhCHCH(SiEt3), was prepared by reaction of [Ru(H)Cl(OC)2(Pri3P)2]1 with AgBF4 in acetone as solvent. The reactivity of 2 has been investigated. This compound reacts with Lewis bases (L) to give [RuH(CO)2L(PPri3)2]BF4[L = H2O 3, MeCN 4, CO 5 or pyrazole (Hpz)6]. Complex 5 can be deprotonated by KOH to afford [Ru(OC)3(Pri3P)2]7, while the reaction of 6 with [{Rh(µ-OMe)(diolefin)}2][diolefin = tetrafluorobenzobarrelene (tfbb) or cycloocta-1,5-diene, (cod)] led to heterobinuclear compounds of formula [(OC)2(Pri3P)2Ru(µ-H)(µ-pz)Rh(diolefin)]BF4(diolefin = tfbb 10 or cod 11). The molecular structure of 11 was determined by an X-ray investigation. Compound 11 crystallises in the orthorhombic space group Fdd2, with cell dimensions a= 28.290(2), b= 22.572(1), c= 23.126(1)A and Z= 16. The structure was refined to R and R′ values of 0.0232 and 0.0258 for 6297 observed reflections. The cation in 11 can be described as a ruthenium–rhodium heterobinuclear species where the metals are connected through a bidentate pyrazolate group and a bridging hydrodo ligand. The metal–metal distance is 3.1323(3)A. Complex 2 reacts with HCl to give [RuCl2(CO)2(PPri3)2]12, which can be also prepared by reaction of [RuCl(η1-OCMe2)(CO)2-(PPri3)2]BF413 with NaCl. This compound in the presence of Lewis bases affords [RuCl(CO)2L-(PPri3)2]BF4(L = H2O 14, MeCN 15, CO 16 or Hpz 17). The reactions of 17 with [{Rh(µ-OMe)(diolefin)}2] lead to [(OC)2(Pri3P)2Ru(µ-Cl)(µ-pz)Rh(diolefin)]BF4(diolefin = tf bb 18 or cod 19). Carbon disulfide, SCNR (R = Me or Ph) and HCCCO2Me, undergo insertion reactions into the Ru–H bond of 2 to give the corresponding insertion products. [Ru(η2-S2CH)(CO)2(PPri3)2]BF420, [Ru{η2-SN(R)CH}(CO)2(PPri3)2]BF4(R = Me 21 or Ph 22) and [[graphic omitted]OMe]CH2}(CO)2(PPri3)2]BF423.