Electrophilicity of Hoveyda‐Grubbs Olefin Metathesis Catalysts as the Driving Force that Controls Initiation Rates. Issue 23 (19th October 2022)

• Record Type: Journal Article
• Authors: Martínez, Juan Pablo; Trzaskowski, Bartosz
• Is Part Of: Chemphyschem. Volume 23:Issue 23(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-10-19
• Subjects: metathesis -- olefins -- initiation rate -- electrophilicity -- density functional calculations; Chemistry, Physical and theoretical -- Periodicals; 541.05
• DOI: 10.1002/cphc.202200580
• Languages: English
• ISSNs: 1439-4235

Abstract

Abstract: The dissociative mechanism of initiation for a series of Hoveyda‐Grubbs type metathesis catalysts modified at the para and meta positions in the isopropoxybenzylidene ligand is investigated by means of DFT calculations. The electron donating/withdrawing capacity of the ligand was screened through the incorporation of various substituents such as halogens, nitro, alkoxides, ketones, esters, amines, and amides. Variations in structural parameters, energy barriers for the Ru−O bond dissociation, and Ru−O bond strength were examined as a function of the Hammett constant. It was found that electronic properties of the catalysts such as chemical potential, hardness, and electrophilicity correlate linearly with the dissociative energy barriers. These findings enable a systematic rationalization and prediction of rate of precatalyst initiation through the calculation of only the HOMO‐LUMO gap of catalysts, as the faster the initiation, the more electrophilic the catalyst. Abstract : The initiation rate of olefin metathesis evaluated through a dissociative mechanism is rationalized and predicted by means of the electrophilicity of the Hoveyda‐Grubbs catalyst, as the faster the initiation, the more electrophilic the catalyst.