Dehydrogenation of formic acid by Ir–bisMETAMORPhos complexes: experimental and computational insight into the role of a cooperative ligand
| Autor: | Jarl Ivar van der Vlugt, Martin Lutz, Bas de Bruin, Sander Oldenhof, Joost N. H. Reek |
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| Přispěvatelé: | Homogeneous and Supramolecular Catalysis (HIMS, FNWI) |
| Rok vydání: | 2015 |
| Předmět: | |
| Zdroj: | Chemical Science, 6(2), 1027-1034. Royal Society of Chemistry |
| ISSN: | 2041-6539 2041-6520 |
| DOI: | 10.1039/c4sc02555e |
| Popis: | The synthesis and tautomeric nature of three xanthene-based bisMETAMORPhos ligands (La-Lc) is reported. Coordination of these bis(sulfonamidophosphines) to Ir(acac)(cod) initially leads to the formation of Ir-I(L-H) species (1a), which convert via formal oxidative addition of the ligand to Ir-III(L) monohydride complexes 2a-c. The rate for this step strongly depends on the ligand employed. Ir-III complexes 2a-c were applied in the base-free dehydrogenation of formic acid, reaching turnover frequencies of 3090, 877 and 1791 h(-1), respectively. The dual role of the ligand in the mechanism of the dehydrogenation reaction was studied by H-1 and P-31 NMR spectroscopy and DFT calculations. Besides functioning as an internal base, bisMETAMORPhos also assists in the pre-assembly of formic acid within the Ir-coordination sphere and aids in stabilizing the rate-determining transition state through hydrogenbonding. |
| Databáze: | OpenAIRE |
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