Degradation pathways of a highly active iron(iii) tetra-NHC epoxidation catalyst

Autor:	Benjamin J. Hofmann, Tim P. Schlachta, Robert M. Reich, Fritz E. Kühn, Florian Dyckhoff, Christian H. G. Jakob, Marco A. Bernd, Jonas F. Schlagintweit
Rok vydání:	2021
Předmět:	biology Dimer Protonation Methylene bridge Nuclear magnetic resonance spectroscopy Photochemistry biology.organism_classification Decomposition Catalysis chemistry.chemical_compound chemistry Tetra Carbene
Zdroj:	Catalysis Science & Technology. 11:795-799
ISSN:	2044-4761 2044-4753
Popis:	Pivotal degradation pathways of the most active non-heme iron epoxidation catalyst to date are investigated in detail. In-depth HR-ESI-MS and NMR spectroscopy decomposition studies and comparative catalytic experiments exclude the generally accepted literature paths of μ2-oxo bridged FeIII–O–FeIII dimer formation and methylene bridge oxidation. Instead, the Fe–NHC bond has been identified as the “weak spot”. It is shown that direct oxidation of one of the carbenes (ImCO) results in its de-coordination and induces protonation of the other NHC moieties, thus completely deactivating the catalyst. Evidence for protonation prior to carbene oxidation has not been found in this study.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::6a0312aee4b02067f2e28795694132f2 https://doi.org/10.1039/d0cy02433c Zobrazit plný text záznamu