The reaction of mixtures of [Rh4(CO)12] and triphenylphosphite with carbon monoxide or syngas as studied by high-resolution, high-pressure NMR spectroscopy
| Autor: | Brian T. Heaton, Robin Whyman, Gillian Overend, Jonathan A. Iggo |
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| Rok vydání: | 2008 |
| Předmět: |
Carbon Monoxide
Magnetic Resonance Spectroscopy Phosphites Chemistry Dimer General Chemistry Nuclear magnetic resonance spectroscopy Partial pressure Homolysis Crystallography chemistry.chemical_compound Fragmentation (mass spectrometry) Organometallic Compounds Pressure Organic chemistry Rhodium General Materials Science Redistribution (chemistry) Syngas Carbon monoxide |
| Zdroj: | Magnetic Resonance in Chemistry. 46:S100-S106 |
| ISSN: | 1097-458X 0749-1581 |
| DOI: | 10.1002/mrc.2314 |
| Popis: | The fragmentation and redistribution reactions of [Rh4(CO)12−x{P(OPh)3}x] (x = 1–4) with carbon monoxide have been studied using high-resolution, high-pressure NMR spectroscopy. Under the conditions of efficient gas mixing in a high-pressure NMR bubble column, [Rh4(CO)9{P(OPh)3}3] fragments to give mainly [Rh2(CO)6{P(OPh)3}2]; [Rh4(CO)11{P(OPh)3}] is also observed, implying redistribution of the phosphite ligand and/or recombination of the dimers to tetrameric clusters. Fragmentation of [Rh4(CO)10{P(OPh)3}2] is found to be pressure-dependent giving predominantly [Rh2(CO)6{P(OPh)3}2] at low CO pressure (1–40 bar), and increasing amounts of [Rh2(CO)7{P(OPh)3}] at higher (40–80 bar) pressure. Using Syngas (CO : H2 (1:1)) instead of CO in the above fragmentations, homolytic addition of H2 to the dimer [Rh2(CO)6{P(OPh)3}2] to give [RhH(CO)3{P(OPh3}] and [RhH(CO)2{P(OPh)3}2] is observed. The distribution of tetrameric species obtained is similar to that obtained under the same partial pressure of CO. On depressurisation/out-gassing of the sample, the original mixture of tetrameric clusters is obtained. Copyright © 2008 John Wiley & Sons, Ltd. |
| Databáze: | OpenAIRE |
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