Olefin Metathesis with Ru-Based Catalysts Exchanging the Typical N-Heterocyclic Carbenes by a Phosphine–Phosphonium YlideReport as inadecuate


Olefin Metathesis with Ru-Based Catalysts Exchanging the Typical N-Heterocyclic Carbenes by a Phosphine–Phosphonium Ylide


Olefin Metathesis with Ru-Based Catalysts Exchanging the Typical N-Heterocyclic Carbenes by a Phosphine–Phosphonium Ylide - Download this document for free, or read online. Document in PDF available to download.

1

Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, Campus Montilivi, 17003 Girona, Catalonia, Spain

2

CNRS, LCC Laboratoire de Chimie de Coordination, 205 Route de Narbonne, BP44099, 31077 Toulouse CEDEX 4, France

3

Université de Toulouse, UPS, ICT-FR 2599, 31062 Toulouse CEDEX 9, France





*

Authors to whom correspondence should be addressed.



Academic Editors: Albert Demonceau, Ileana Dragutan and Valerian Dragutan

Abstract Density functional theory DFT calculations have been used to describe the first turnover of an olefin metathesis reaction calling for a new in silico family of homogenous Ru-based catalysts bearing a phosphine–phosphonium ylide ligand, with ethylene as a substrate. Equal to conventional Ru-based catalysts bearing an N-heterocyclic carbene NHC ligand, the activation of these congeners occurs through a dissociative mechanism, with a more exothermic first phosphine dissociation step. In spite of a stronger electron-donating ability of a phosphonium ylide C-ligand with respect to a diaminocarbene analogue, upper energy barriers were calculated to be on average ca. 5 kcal-mol higher than those of Ru–NHC standards. Overall, the study also highlights advantages of bidentate ligands over classical monodentate NHC and phosphine ligands, with a particular preference for the cis attack of the olefin. The new generation of catalysts is constituted by cationic complexes potentially soluble in water, to be compared with the typical neutral Ru–NHC ones. View Full-Text

Keywords: olefin metathesis; ruthenium; NHC; phosphine-phosphonium ylide; N-heterocyclic carbene; catalysis olefin metathesis; ruthenium; NHC; phosphine-phosphonium ylide; N-heterocyclic carbene; catalysis





Author: Laia Arnedo 1, Remi Chauvin 2,3,* and Albert Poater 2,*

Source: http://mdpi.com/



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