Abstract
C−O bond activation of DPEphos occurs upon mild heating in the presence of [Ru(NHC) 2(PPh 3) 2H 2] (NHC=N-heterocyclic carbene) to form phosphinophenolate products. When NHC=IEt 2Me 2, C−O activation is accompanied by C−N activation of an NHC ligand to yield a coordinated N-phosphino-functionalised carbene. DFT calculations define a nucleophilic mechanism in which a hydride ligand attacks the aryl carbon of the DPEphos C−O bond. This is promoted by the strongly donating NHC ligands which render a trans dihydride intermediate featuring highly nucleophilic hydride ligands accessible. C−O bond activation also occurs upon heating cis-[Ru(DPEphos) 2H 2]. DFT calculations suggest this reaction is promoted by the steric encumbrance associated with two bulky DPEphos ligands. Our observations that facile degradation of the DPEphos ligand via C−O bond activation is possible under relatively mild reaction conditions has potential ramifications for the use of this ligand in high-temperature catalysis.
Original language | English |
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Pages (from-to) | 11141-11145 |
Number of pages | 5 |
Journal | Chemistry - A European Journal |
Volume | 26 |
Early online date | 19 May 2020 |
DOIs | |
Publication status | Published - 26 Aug 2020 |
Keywords
- C−O bond activation
- N-heterocyclic carbenes
- density functional calculations
- hydride ligands
- phosphines
ASJC Scopus subject areas
- Catalysis
- Organic Chemistry