112287-52-2Relevant academic research and scientific papers
Nucleophilic attack on η3-allyl and η 2-tetrahydroborate complexes of ruthenium(II)
Chamberlain, Barbara,Duckett, Simon B.,Lowe, John P.,Mawby, Roger J.,Stott, J. Claire
, p. 2603 - 2614 (2007/10/03)
Reaction of [Ru(CO)(η3-C3H 5)Cl(PMe2Ph)2], 1, with CO and Ag+ yielded 2A and 2B, isomers of [Ru(CO)2-(η3-C 3H5)(PMe2Ph)2]+. Treatment of 2B with BH4- gave [Ru(CO)2(CH 2CH2CH2)(PMe2Ph)2], 7, and [Ru(η2-BH4)-(CO)H(PMe2Ph)2], 6, subsequently obtained from [Ru2(CO)2Cl 4(PMe2Ph)4] and NaBH4. Chloride attacked the metal in 2B, yielding [Ru(CO)2(η1-C 3H5)Cl(PMe2Ph)2], 8, which then reformed 1. Lability of the Ru-HB bond trans to hydride allowed nucleophilic access to the metal in 6, with low-temperature formation of [Ru(η 1-BH4)(CO)-H(L)(PMe2Ph)2] (11, 12, 13, L = PMe2Ph, CO, 4-methylpyridine, respectively). On warming with excess L, these gave H3B·L and [Ru(CO)(H) 2L(PMe2Ph)2] (5, 4, 14, respectively). For L = C2H4, low-temperature NMR studies revealed a rapid equilibrium between 6, C2H4 and [Ru(η 1-BH4)(CO)(η2-C2H 4)H(PMe2Ph)2], 16, with slower conversion to [Ru(η2-BH4)(CO)Et(PMe2Ph)2], 17. The Royal Society of Chemistry 2003.
Ruthenium dihydride complexes: NMR studies of intramolecular isomerization and fluxionality including the detection of minor isomers by parahydrogen-induced polarization
Schott, Daniele,Sleigh, Christopher J.,Lowe, John P.,Duckett, Simon B.,Mawby, Roger J.,Partridge, Martin G.
, p. 2960 - 2970 (2008/10/08)
NMR studies reveal that complexes Ru(CO)2(H)2L2 (L = PMe3, PMe2Ph, and AsMe2Ph) can have three geometries, ccc, cct-L, and cct-CO, with equilibrium ratios that are highly dependent on the electronic properties of L; the cct-L form is favored, because the σ-only hydride donor is located trans to CO rather than L. When L = PMe3, the ccc form is only visible when p-H2 is used to amplify its spectral features. In contrast, when L = AsMe2Ph, the ccc and cct-L forms are present in similar quantities and, hence, must have similar free energies; for this complex, however, the cct-CO isomer is also detectable. These complexes undergo a number of dynamic processes. For L2 = dppe, an interchange of the hydride positions within the ccc form is shown to be accompanied by synchronized CO exchange and interchange of the two phosphorus atoms. This process is believed to involve the formation of a trigonal bipyramidal transition state containing an η/2-H2 ligand; in view of the fact that kHH/kDD is 1.04 and the synchronized rotation when L2 = dppe, this transition state must contain little H-H bonding character. Pathways leading to isomer interconversion are suggested to involve related structures containing η2-H2 ligands. The inverse kinetic isotope effect, kHH/kDD = 0.5, observed for the reductive elimination of dihydrogen from Ru(CO)2(H)2dppe suggests that substantial H-H bond formation occurs before the H2 is actually released from the complex. Evidence for a substantial steric influence on the entropy of activation explains why Ru(CO)2(H)2dppe undergoes the most rapid hydride exchange. Our studies also indicate that the species [Ru(CO)2L2], involved in the addition of H2 to form Ru(CO)2(H)2L2, must have singlet electron configurations.
Preparation, Isomerization, and Reactions of Hydride Complexes of Ruthenium(II)
Bray, Joanne M.,Mawby, Roger J.
, p. 2989 - 2994 (2007/10/02)
Hydride complexes 2> (X = H or Cl, L = PMe2Ph or AsMe2Ph) and their deuteride analogues have been prepared.The complex exists in solution as an equilibrium mixture of isomers.The dideuteride exchanges with H2 in solution: no is formed, suggesting that exchange occurs via .Exchange also occurs with ethene and propene: here is observed.Ethene is hydrogenated by 2>, with formation of ethane and complexes 2>, which are reconverted to 2> by H2.The terminal alkenes 1-hexene and 3-phenylpropene are isomerized by 2>: for L = AsMe2Ph, a little hydrogenation of 3-phenylpropene also occurs.
