Cargando…
A bench stable formal Cu(iii) N-heterocyclic carbene accessible from simple copper(ii) acetate
For years, Cu(iii)NHCs have been proposed as active intermediates in Cu(i)NHC catalyzed reactions, yielding the desired products by reductive elimination, but until today, no one has ever reported the characterisation of such a compound. When working on the synthesis of biomimetic transition metal (...
Autores principales: | , , , , , , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Royal Society of Chemistry
2018
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6240905/ https://www.ncbi.nlm.nih.gov/pubmed/30542579 http://dx.doi.org/10.1039/c8sc01834k |
_version_ | 1783371709047373824 |
---|---|
author | Ghavami, Zohreh S. Anneser, Markus R. Kaiser, Felix Altmann, Philipp J. Hofmann, Benjamin J. Schlagintweit, Jonas F. Grivani, Gholamhossein Kühn, Fritz E. |
author_facet | Ghavami, Zohreh S. Anneser, Markus R. Kaiser, Felix Altmann, Philipp J. Hofmann, Benjamin J. Schlagintweit, Jonas F. Grivani, Gholamhossein Kühn, Fritz E. |
author_sort | Ghavami, Zohreh S. |
collection | PubMed |
description | For years, Cu(iii)NHCs have been proposed as active intermediates in Cu(i)NHC catalyzed reactions, yielding the desired products by reductive elimination, but until today, no one has ever reported the characterisation of such a compound. When working on the synthesis of biomimetic transition metal (NHC) complexes and their application in homogeneous catalysis, we recently found a highly unusual reactivity for Cu(ii) acetate in the presence of a particular cyclic tetra(NHC) ligand. Therein, the formation of the first stable CuNHC compound, displaying Cu in the formal oxidation state +III, by simple disproportionation of Cu(ii) acetate in dimethyl sulfoxide (DMSO) was observed. At elevated temperatures selective mono-oxidation of the NHC ligand occurs, even under anaerobic conditions. Acetate was identified as the origin of the oxygen atom by (18)O-labelling experiments. The remarkably high stability of the title compound was furthermore proven electrochemically by cyclic voltammetry. An in-depth investigation of its reactivity revealed the involvement of four additional compounds. Three of them could be isolated and characterised by (1)H/(13)C-NMR, single crystal XRD, mass spectrometry and elemental analysis. The fourth, a Cu(i)NHC intermediate, formed by formal reductive elimination from the Cu(NHC)(3+) compound, was characterised in situ by (1)H/(13)C-NMR and computational methods. |
format | Online Article Text |
id | pubmed-6240905 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2018 |
publisher | Royal Society of Chemistry |
record_format | MEDLINE/PubMed |
spelling | pubmed-62409052018-12-12 A bench stable formal Cu(iii) N-heterocyclic carbene accessible from simple copper(ii) acetate Ghavami, Zohreh S. Anneser, Markus R. Kaiser, Felix Altmann, Philipp J. Hofmann, Benjamin J. Schlagintweit, Jonas F. Grivani, Gholamhossein Kühn, Fritz E. Chem Sci Chemistry For years, Cu(iii)NHCs have been proposed as active intermediates in Cu(i)NHC catalyzed reactions, yielding the desired products by reductive elimination, but until today, no one has ever reported the characterisation of such a compound. When working on the synthesis of biomimetic transition metal (NHC) complexes and their application in homogeneous catalysis, we recently found a highly unusual reactivity for Cu(ii) acetate in the presence of a particular cyclic tetra(NHC) ligand. Therein, the formation of the first stable CuNHC compound, displaying Cu in the formal oxidation state +III, by simple disproportionation of Cu(ii) acetate in dimethyl sulfoxide (DMSO) was observed. At elevated temperatures selective mono-oxidation of the NHC ligand occurs, even under anaerobic conditions. Acetate was identified as the origin of the oxygen atom by (18)O-labelling experiments. The remarkably high stability of the title compound was furthermore proven electrochemically by cyclic voltammetry. An in-depth investigation of its reactivity revealed the involvement of four additional compounds. Three of them could be isolated and characterised by (1)H/(13)C-NMR, single crystal XRD, mass spectrometry and elemental analysis. The fourth, a Cu(i)NHC intermediate, formed by formal reductive elimination from the Cu(NHC)(3+) compound, was characterised in situ by (1)H/(13)C-NMR and computational methods. Royal Society of Chemistry 2018-09-14 /pmc/articles/PMC6240905/ /pubmed/30542579 http://dx.doi.org/10.1039/c8sc01834k Text en This journal is © The Royal Society of Chemistry 2018 https://creativecommons.org/licenses/by/3.0/This article is freely available. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence (CC BY 3.0) |
spellingShingle | Chemistry Ghavami, Zohreh S. Anneser, Markus R. Kaiser, Felix Altmann, Philipp J. Hofmann, Benjamin J. Schlagintweit, Jonas F. Grivani, Gholamhossein Kühn, Fritz E. A bench stable formal Cu(iii) N-heterocyclic carbene accessible from simple copper(ii) acetate |
title | A bench stable formal Cu(iii) N-heterocyclic carbene accessible from simple copper(ii) acetate
|
title_full | A bench stable formal Cu(iii) N-heterocyclic carbene accessible from simple copper(ii) acetate
|
title_fullStr | A bench stable formal Cu(iii) N-heterocyclic carbene accessible from simple copper(ii) acetate
|
title_full_unstemmed | A bench stable formal Cu(iii) N-heterocyclic carbene accessible from simple copper(ii) acetate
|
title_short | A bench stable formal Cu(iii) N-heterocyclic carbene accessible from simple copper(ii) acetate
|
title_sort | bench stable formal cu(iii) n-heterocyclic carbene accessible from simple copper(ii) acetate |
topic | Chemistry |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6240905/ https://www.ncbi.nlm.nih.gov/pubmed/30542579 http://dx.doi.org/10.1039/c8sc01834k |
work_keys_str_mv | AT ghavamizohrehs abenchstableformalcuiiinheterocycliccarbeneaccessiblefromsimplecopperiiacetate AT annesermarkusr abenchstableformalcuiiinheterocycliccarbeneaccessiblefromsimplecopperiiacetate AT kaiserfelix abenchstableformalcuiiinheterocycliccarbeneaccessiblefromsimplecopperiiacetate AT altmannphilippj abenchstableformalcuiiinheterocycliccarbeneaccessiblefromsimplecopperiiacetate AT hofmannbenjaminj abenchstableformalcuiiinheterocycliccarbeneaccessiblefromsimplecopperiiacetate AT schlagintweitjonasf abenchstableformalcuiiinheterocycliccarbeneaccessiblefromsimplecopperiiacetate AT grivanigholamhossein abenchstableformalcuiiinheterocycliccarbeneaccessiblefromsimplecopperiiacetate AT kuhnfritze abenchstableformalcuiiinheterocycliccarbeneaccessiblefromsimplecopperiiacetate AT ghavamizohrehs benchstableformalcuiiinheterocycliccarbeneaccessiblefromsimplecopperiiacetate AT annesermarkusr benchstableformalcuiiinheterocycliccarbeneaccessiblefromsimplecopperiiacetate AT kaiserfelix benchstableformalcuiiinheterocycliccarbeneaccessiblefromsimplecopperiiacetate AT altmannphilippj benchstableformalcuiiinheterocycliccarbeneaccessiblefromsimplecopperiiacetate AT hofmannbenjaminj benchstableformalcuiiinheterocycliccarbeneaccessiblefromsimplecopperiiacetate AT schlagintweitjonasf benchstableformalcuiiinheterocycliccarbeneaccessiblefromsimplecopperiiacetate AT grivanigholamhossein benchstableformalcuiiinheterocycliccarbeneaccessiblefromsimplecopperiiacetate AT kuhnfritze benchstableformalcuiiinheterocycliccarbeneaccessiblefromsimplecopperiiacetate |