|
authors |
Gomes, AC; Bruno, SM; Gago, S; Lopes, RP; Machado, DA; Carminatti, AP; Valente, AA; Pillinger, M; Goncalves, IS |
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nationality |
International |
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journal |
JOURNAL OF ORGANOMETALLIC CHEMISTRY |
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author keywords |
Molybdenum; Schiff base ligands; Carbonyl ligands; Supported catalysts; Oxidative decarbonylation; Olefin epoxidation |
|
keywords |
MICROWAVE-ASSISTED SYNTHESIS; DERIVATIZED DIIMINE LIGANDS; TEMPERATURE IONIC LIQUIDS; TERT-BUTYL HYDROPEROXIDE; NITROGEN DONOR LIGANDS; SCHIFF-BASE LIGANDS; CARBONYL-COMPLEXES; OLEFIN EPOXIDATION; CRYSTAL-STRUCTURE; METHYL-METHACRYLATE |
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abstract |
The ligand N-(n-propyl)-2-pyridylmethanimine (pyim) and an immobilised analogue of this ligand (MCM-41-pyim) were prepared by the condensation reaction of 2-pyridinecarboxaldehyde with either propylamine or aminopropyl groups covalently attached to the ordered mesoporous silica MCM-41. Free and immobilised tetracarbonyl complexes of the type cis-[Mo(CO)(4)(L)] (L = pyim (1), MCM-41-pyim) were then prepared by microwave-assisted heating of a mixture of Mo(CO)(6) and the organic ligand or ligand-silica in toluene at 110 degrees C for 30-45 min. The products were characterised by NMR spectroscopy ((1)H, (13)C and (29)Si, in solution and in the solid state), elemental analysis, N(2) adsorption, and FT-IR spectroscopy. When used as catalyst precursors for the epoxidation of cis-cyclooctene by tert-butylhydroperoxide at 55 degrees C (1 mol% catalyst (Mo), no additional co-solvent), 1,2-epoxy-cyclooctane was obtained as the only reaction product in quantitative yield after 5 h for 1 and 36% yield after 24 h for the supported complex. The use of the ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate as co-solvent led to lower catalytic activities (epoxide selectivity was always 100%) but allowed the catalyst/IL mixtures (homogeneous mixture for IL+1 and a biphasic solid + IL system for IL+MCM-41-pyim/Mo) to be easily recovered and reused in subsequent runs without loss of catalytic performance. (C) 2011 Elsevier B. V. All rights reserved. |
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publisher |
ELSEVIER SCIENCE SA |
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issn |
0022-328X |
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year published |
2011 |
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volume |
696 |
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issue |
22 |
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beginning page |
3543 |
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ending page |
3550 |
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digital object identifier (doi) |
10.1016/j.jorganchem.2011.07.040 |
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web of science category |
Chemistry, Inorganic & Nuclear; Chemistry, Organic |
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subject category |
Chemistry |
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unique article identifier |
WOS:000295717300013
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