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Dissymmetric gold(I) N-heterocyclic carbene complexes: a key unexpected structural parameter for highly efficient
Mohamed Bouhrara1, Erwan Jeanneau, Laurent Veyre
1Université de Lyon, Institut de Chimie de Lyon, C2P2 UMR 5265 (CNRS-CPE Lyon-Université Lyon 1) ESCPE Lyon 43, Bd du 11 Novembre 1918, F-69616, Villeurbanne, France.
Abstract:
Gold(I) N-heterocyclic carbene complexes (Au-NHC) with symmetric (bis-benzyl, -propyl and -mesityl substituents) and dissymmetric (mesityl and alkyl--benzyl or propyl--substituents) NHC ligands were synthesized and tested as catalysts for the addition of methanol to 3-hexyne, as a representative internal alkyne. While symmetric ones--bis-alkyl (propyl or benzyl) or bis-mesityl systems--displayed low activity, dissymmetric Au-NHC systems with one alkyl (benzyl or propyl) and one mesityl groups on the NHC unit were unexpectedly highly active with rates and turnover numbers up to 294,000 h(-1) and 800,000 mol.mol(Au)(-1).
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