Ru3(CO)12in Acidic Media. Intermediates of the Acid-Cocatalyzed Water-Gas Shift Reaction (WGSR)
- 1 January 1996
- journal article
- research article
- Published by American Chemical Society (ACS) in Inorganic Chemistry
- Vol. 35 (25) , 7217-7224
- https://doi.org/10.1021/ic960630v
Abstract
The elucidation of the WGSR promoted by ruthenium carbonyls in acidic media started with the detection of the Ru(0), Ru(I), and Ru(II) intermediate complexes, namely Ru3(CO)12, Ru2[μ-η2-OC(CF3)O]2(CO)6, and fac-[Ru(CF3COO)3(CO)3]-, which accumulate when CF3COOH is employed as an acid cocatalyst. Under catalytic conditions, the three were found to interconvert through elementary steps which produce CO2 and H2. In fact, Ru(0) is oxidized by H+ to Ru(I) and half the hydrogen of the catalytic cycle is supplied by this reaction. On the other hand, Ru(I) disproportionates to Ru(0) and Ru(II), and this latter species undergoes nucleophilic attack by H2O. The decomposition of the metallacarboxylic acid intermediate gives back Ru(I), while H2 and CO2 are produced in a 1/2 molar ratio. The two alternating pathways for dihydrogen formation, namely Ru(0) oxidation by H+ and the decomposition of a metallacarboxylic acid intermediate, involve H2 reductive elimination from the same RuHCF3COO(CO)2L2 intermediate (L = H2O, ethers). These findings define an acid-cocatalyzed WGSR whose distinctive features are (i) the intervention of a disproportionation reaction to generate a Ru(II) electron poor complex, whose CO ligands can undergo nucleophilic attack by water, (ii) the generation of the hydrido intermediate for dihydrogen production through two distinct reaction patways, and (iii) the reductive elimination of H2 from the hydrido intermediate without involving H+ from the medium.Keywords
This publication has 15 references indexed in Scilit:
- Hydridosulphonato, hydridocarboxylato and cationic hydrido complexes of carbonylpyridine ruthenium(II)Journal of Organometallic Chemistry, 1995
- Homogeneous WGS Reaction Promoted by Rhodium Carbonyls in Aqueous Pyridine: An Acid-Cocatalyzed Reaction Which Proceeds to the Complete Consumption of Water and Is Inhibited by Chloride IonsInorganic Chemistry, 1994
- Addition of carboxylic acids to alkynes catalysed by ruthenium complexesJournal of Organometallic Chemistry, 1993
- Homogeneous catalysis of the water-gas shift reactionJournal of Molecular Catalysis, 1988
- Chemistry of bridged carboxylate ruthenium complexes. Crystal structures of [Ru(PhCOO)(CO)2(PhCOOH]2, [Ru(4-FC6H4COO)2(CO)5(H2O)]2·0.5 C6H6, and [Ru2(s-BuCO2)2(CO)4(s-BuCO2H)]2Journal of Organometallic Chemistry, 1986
- Organometallic chemistry of fluorocarbon acids. Synthesis, structure, and solvolysis of a sulfinate-bridged diruthenium dihydride cluster, [(Ph3P)4Ru2(.mu.-H)2(.mu.-CF3SO2)(CO)2][HC(SO2CF3)2]Inorganic Chemistry, 1986
- On enantiomorph-polarity estimationActa Crystallographica Section A Foundations of Crystallography, 1983
- Homogeneous Catalysis of the Water Gas Shift Reaction by Metal CarbonylsPublished by American Chemical Society (ACS) ,1979
- Simultaneous carbonylation and homologation of dimethyl ether and homologation of methyl acetate to ethyl acetate in the presence of ruthenium catalystsJournal of the American Chemical Society, 1978
- Hydride complexes of the transition metalsChemical Reviews, 1972