Description succincte
(Anglais)
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The aim of the project is the better understanding of the fundamental aspects of homogeneous catalytic activation of CO, H2, N2, and CO2, as well as small alkenes and alkynes using in situ high pressure spectroscopic methods. The practical goal is to identify improved reaction parameters and new pathways for chemical syntheses.
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Partenaires et organisations internationales
(Anglais)
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BE, BG, CH, CZ, DE, DK, ES, FI, FR, HU, IT, NL, PL, PT, RO, SE, SI, UK
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Résumé des résultats (Abstract)
(Anglais)
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1) We have studied the catalytic hydrocarboxylation of linear alkenes to obtain carboxylic acids using supercritical carbon dioxide as a solvent. High selectivities in acids have been obtained. The best results were achieved by adding a perfluorinated surfactant to the reaction mixture (93 % conversions and ca 80 % selectivity). Our comparative multinuclear high pressure NMR studies in THFd8 and in supercritical CO2 show the formation of Pd(0) species. 2) We have carried out the catalytic hyrodehalogenation of a series of arylhalides in [emim][BF4] ionic liquid. Pd on active C was found to be a more effective catalyst than any of the Pd(II) complexes investigated. As H2 source, the triethylammonium formate afforded better conversion than pressurised H2, or Na-, NH4- or Me4N-formates, due to its higher solubility. At 90°C the selectivity was as expected: iodobenzene was more readily dehalogenated than bromobenzene, which in turn yielded better results than chlorobenzene. 3) We have investigated some iridium N-heterocyclic carbene (NHC) complexes for catalytic applications. From the [IrCl(bmim)(cod)] (bmim = 1-butyl-3-methylimidazol-2-yliden; cod = 1,5cyclooctadiene), neutral compound, we have synthesized new water soluble complexes: [Ir(bmim)(cod)(P)], [Ir(bmim)(cod)(S)]CF3SO3 and [IrH2(bmim)(NCMe)2(mtppts)]Cl, (where P= mtppms, mtppds, mtppts; mtppts = 3,3’,3’’- trisulfonated triphenylphosphine, mtppds = 3,3’’- disulfonated triphenylphosphine mtppms = 3-diphenylphosphinobenzenesulfonic acid, and S = solvent). All these compounds were characterised by NMR, ESI, and IR, and for [IrCl(bmim)(cod)] and [Ir(bmim)(cod)(H2O)]CF3SO3 the crystal structures have been determined by X-ray diffraction. These complexes were used as catalyst precursors in CO2/bicarbonate hydrogenation reactions and in water. Generally these compounds showed good catalytic activity. 4) We have studied the equilibrium and formation conditions of several new classical and nonclassical hydrides of Ru(II) in aqueous solution, usind the water soluble mtppms ligands. In the aqueous solutions of [{RuCl2(mtppms)2}2] + mtppms (mtppms = meta-monosulfonated triphenylphosphine) pressurized with 1-100 bar H2, we have detected two new hydride species in addition to the earlier characterised [{RuHCl(mtppms)2}2], [RuHCl(mtppms)3] and [RuH2(mtppms)4]: the cis[ RuH2(H2)(mtppms)3] and the trans-[RuH2(mtppms)4].
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