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Nova generació de catalitzadors de metàtesi d’olefines : la substitució de NHC per ilur de fosfoni

Density functional theory calculations (DFT) have been used to describe the first turnover for olefin metathesis reaction of a new in silico family of homogenous Ru-based catalysts bearing a phosphoylide ligand with ethylene as a substrate. Equal to conventional Rubased catalysts for olefin metathesis that bear a N-heterocyclic carbene (NHC) ligand, the activation of these congeners occurs through a dissociative mechanism, with a more exothermic first phosphine dissociative step. However, predicted upper energy barriers were calculated to be on average ~5 kcal/mol less beneficial with respect to the Ru-NHC based catalysed metathesis. Overall, this present computational study emphasises on advantages of bidentate ligands to replace the NHC ligand of Ru-based metathesis and gives a potential recipe for the design of efficient Ru-based olefin metathesis catalysts. The new generation of catalysts is cationic, however the addition of a chloride instead of the phosphine seems to be favourable and with better performance in terms of both kinetics and thermodynamics

Manager: Poater Teixidor, Albert
Other contributions: Universitat de Girona. Facultat de Ciències
Author: Arnedo Marimon, Laia
Date: 2016 September
Abstract: Density functional theory calculations (DFT) have been used to describe the first turnover for olefin metathesis reaction of a new in silico family of homogenous Ru-based catalysts bearing a phosphoylide ligand with ethylene as a substrate. Equal to conventional Rubased catalysts for olefin metathesis that bear a N-heterocyclic carbene (NHC) ligand, the activation of these congeners occurs through a dissociative mechanism, with a more exothermic first phosphine dissociative step. However, predicted upper energy barriers were calculated to be on average ~5 kcal/mol less beneficial with respect to the Ru-NHC based catalysed metathesis. Overall, this present computational study emphasises on advantages of bidentate ligands to replace the NHC ligand of Ru-based metathesis and gives a potential recipe for the design of efficient Ru-based olefin metathesis catalysts. The new generation of catalysts is cationic, however the addition of a chloride instead of the phosphine seems to be favourable and with better performance in terms of both kinetics and thermodynamics
Format: application/pdf
Document access: http://hdl.handle.net/10256/12980
Language: cat
Collection: Biologia (TFG)
Rights: Attribution-NonCommercial-NoDerivs 3.0 Spain
Rights URI: http://creativecommons.org/licenses/by-nc-nd/3.0/es/
Subject: Alkenes
Metathesis (Chemistry)
Ruthenium Catalysts
Alquens
Metàtesi (Química)
Catalitzadors de ruteni
Title: Nova generació de catalitzadors de metàtesi d’olefines : la substitució de NHC per ilur de fosfoni
Type: info:eu-repo/semantics/bachelorThesis
Repository: DUGiDocs

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