36620-55-0Relevant articles and documents
Exceedingly Facile Ph-X Activation (X=Cl, Br, I) with Ruthenium(II): Arresting Kinetics, Autocatalysis, and Mechanisms
Miloserdov, Fedor M.,McKay, David,Mu?oz, Bianca K.,Samouei, Hamidreza,MacGregor, Stuart A.,Grushin, Vladimir V.
supporting information, p. 8466 - 8470 (2015/11/27)
[(Ph3P)3Ru(L)(H)2] (where L=H2 (1) in the presence of styrene, Ph3P (3), and N2 (4)) cleave the Ph-X bond (X=Cl, Br, I) at RT to give [(Ph3P)3RuH(X)] (2) and PhH. A combined experimental and DFT study points to [(Ph3P)3Ru(H)2] as the reactive species generated upon spontaneous loss of L from 3 and 4. The reaction of 3 with excess PhI displays striking kinetics which initially appears zeroth order in Ru. However mechanistic studies reveal that this is due to autocatalysis comprising two factors: 1) complex 2, originating from the initial PhI activation with 3, is roughly as reactive toward PhI as 3 itself; and 2) the Ph-I bond cleavage with the just-produced 2 gives rise to [(Ph3P)2RuI2], which quickly comproportionates with the still-present 3 to recover 2. Both the initial and onward activation reactions involve PPh3 dissociation, PhI coordination to Ru through I, rearrangement to a η2-PhI intermediate, and Ph-I oxidative addition.
Hydrogen Production from Ethanol catalysed by Group 8 Metal Complexes
Morton, David,Cole-Hamilton, David J.,Utuk, Imelda D.,Paneque-Sosa, Marguerita,Lopez-Poveda, Manuel
, p. 489 - 496 (2007/10/02)
Different strategies for the catalytic thermal production of hydrogen from ethanol are discussed and demonstrated using various Group 8 metal catalysts, in the presence of added base.Where the metal has a low affinity for carbon monoxide, e.g. in +, simple dehydrogenation of ethanol to ethanal and its aldol condensation products is observed.When the metal has a high affinity for CO, CO abstraction from the formed ethanol occurs and, as in reactions catalysed by or i3)3>, can poison the reaction.In some cases, the CO abstraction reaction can be used to promote the thermodynamically favourable reactionof formation of hydrogen, methane, and carbon monoxide; although irradiation with visible light is often required to release the carbon monoxide from the metal centre e.g. i3)2> in the absence of base.Finally, in catalytic reactions carried out in the presence of base, water-gas shift type chemistry is observed in reactions catalysed by Cl, so that ethanol can be converted into 2H2, Ch4, and CO2.In the cases of , rates of hydrogen production of >100 catalyst turnovers h-1, corresponding to >1 l per litre of catalyst solution per hour can readily be sustained over long periods.The role of base in, and the mechanisms of , these interesting reactions are discussed; as are synergistic effects and reasons for the success of Cl and as catalysts for hydrogen production.
HYDRIDO(PHOSPHINE)RUTHENATE COMPLEXES AND THEIR ROLE IN THE CATALYTIC HYDROGENATION OF ARENES
Fordyce, William A.,Wilczynski, Robert,Halpern, Jack
, p. 115 - 126 (2007/10/02)
Starting with the potassium salt of (1), the following reactions in THF were identified: (1) 1+H2 -> fac-- (2); (2) 1+1,4-Ph2-1,3-butadiene -> - (3) + PPh3; (3) 3+4H2 -> - (4) + 1,4-Ph2-butane; (4) 4 + 1-hexene -> - (5) + hexane; (5) 4 + L -> - + H2 (L = CO, PPh3, PMe2Ph); (6) 2 + 1,5-anthracene (A) -> - (7) + 0.5 (1,2,3,4-H4A) + PPh3; (7) 4 + 5 C2H4 -> (8) + 3C2H6; (8) 4 + 2A -> 7 + 1,2,3,4-H4A; (9) 7 + 4H2 -> 4 + 1,2,3,4-H4A.Reactions 8 and 9 constitute a catalytic cycle for the hydrogenation of anthracene to 1,2,3,4-tetrahydroanthracene.
