000059813 001__ 59813
000059813 005__ 20190527111533.0
000059813 0247_ $$2doi$$a10.1002/chem.200390098
000059813 022__ $$a0947-6539
000059813 037__ $$aARTICLE
000059813 245__ $$aCatalytic hydrogenation by triruthenium clusters: A mechanistic study with parahydrogen-induced polarization
000059813 260__ $$c2003
000059813 269__ $$a2003
000059813 336__ $$aJournal Articles
000059813 520__ $$aThe reactivity of the cluster family [Ru-3(CO)(12-x)(L)x] (in which L = PMe3, PMe2Ph, PPh3 and PCy3, x = 1 - 3) towards hydrogen is described. When x=2, three isomers of [Ru-3(H)(mu-H)(CO)(9)(L)(2)] are formed, which differ in the arrangement of their equatorial phosphines. Kinetic studies reveal the presence of intra- and inter-isomer exchange processes with activation parameters and solvent effects indicating the involvement of ruthenium-ruthenium bond heterolysis and CO loss, respectively. When x = 3, reaction with H-2 proceeds to form identical products to those found with x = 2, while when x = 1 a single isomer of [Ru-3(H)(mu-H)(CO)(10)(L)] is formed. Species [Ru-3(H)(mu-H)(CO)(9)(L)(2)] have been shown to play a kinetically significant role in the hydrogenation of an alkyne substrate through initial CO loss, with rates of H-2 transfer being explicitly determined for each isomer. A less significant secondary reaction involving loss of L yields a detectable product that contains both a pendant vinyl unit and a bridging hydride ligand. Competing pathways that involve fragmentation to form [Ru(H)(2)(CO)(2)(L)(alkyne)] are also observed and shown to be favoured by nonpolar solvents. Kinetic data reveal that catalysis based on [Ru-3(CO)(10)(PPh3)(2)] is the most efficient although [Ru-3(H)(mu-H)(CO)(9)(PMe3)(2)] corresponds to the most active of the detected intermediates.
000059813 6531_ $$al = pph3
000059813 6531_ $$anuclear-magnetic-resonance
000059813 6531_ $$aenergy fluxional process
000059813 6531_ $$abridgedmetal-clusters
000059813 6531_ $$ac-h bond
000059813 6531_ $$ahomogeneous catalysis
000059813 6531_ $$aruthenium clusters
000059813 6531_ $$asubstituted derivatives
000059813 6531_ $$acarbonyl substitution
000059813 6531_ $$aorganometallic chemistry
000059813 700__ $$aBlazina, D
000059813 700__ $$aDuckett, SB
000059813 700__ $$0240015$$g149418$$aDyson, PJ
000059813 700__ $$aLohmann, JAB
000059813 773__ $$j9$$tChemistry-A European Journal$$k5$$q1046-1061
000059813 909C0 $$xU9$$0252010$$pLCOM
000059813 909CO $$pSB$$particle$$ooai:infoscience.tind.io:59813
000059813 937__ $$aLCOM-ARTICLE-2003-007
000059813 970__ $$aISI:000181474400003/LCOM
000059813 973__ $$rREVIEWED$$sPUBLISHED$$aEPFL
000059813 980__ $$aARTICLE