How does the addition of steric hindrance to a typical N-heterocyclic carbene ligand affect catalytic activity in olefin metathesis?

Autor: Poater A; Institut de Química Computacional, Departament de Química, Universitat de Girona, Campus de Montilivi, E-17071 Girona, Catalonia, Spain. albert.poater@udg.edu, Falivene L, Urbina-Blanco CA, Manzini S, Nolan SP, Cavallo L
Jazyk: angličtina
Zdroj: Dalton transactions (Cambridge, England : 2003) [Dalton Trans] 2013 May 28; Vol. 42 (20), pp. 7433-9.
DOI: 10.1039/c3dt32980a
Abstrakt: Density functional theory (DFT) calculations were used to predict and rationalize the effect of the modification of the structure of the prototype 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) N-heterocyclic carbene (NHC) ligand. The modification consists in the substitution of the methyl groups of ortho isopropyl substituent with phenyl groups, and here we plan to describe how such significant changes affect the metal environment and therefore the related catalytic behaviour. Bearing in mind that there is a significant structural difference between both ligands in different olefin metathesis reactions, here by means of DFT we characterize where the NHC ligand plays a more active role and where it is a simple spectator, or at least its modification does not significantly change its catalytic role/performance.
Databáze: MEDLINE