Issue 14, 2006
From the journal:

Dalton Transactions

The influence of N-substitution on the reductive elimination behaviour of hydrocarbyl–palladium–carbene complexes—a DFT study†

David C. Graham,a   Kingsley J. Cavellb  and  Brian F. Yates*a  

* Corresponding authors

a School of Chemistry, University of Tasmania, Private Bag 75, Hobart, Tasmania, Australia
E-mail: Brian.Yates@utas.edu.au
Fax: +61 3 6226 2858
Tel: +61 3 6226 2167

b Chemistry Department, Cardiff University, Park Place, Cardiff, UK
E-mail: cavellkj@cardiff.ac.uk
Fax: +44 29 2087 5899
Tel: +44 29 2087 5899

Abstract

The reductive elimination of 2-hydrocarbyl-imidazolium salts from hydrocarbyl–palladium complexes bearing N-heterocyclic carbene (NHC) ligands represents an important deactivation route for catalysts of this type. We have explored the influence that carbene N-substituents have on both the activation energy and the overall thermodynamics of the reductive elimination reaction using density functional theory (DFT). Given the proximity of the N-substituent to the three-centred transition structure, steric bulk has little influence on the activation barrier and it is electronic factors that dominate the barriers' magnitude. Increased electron donation from the departing NHC ligand acts to stabilise the associated complex against reductive elimination, with stability following the trend: Cl < H < Ph < Me < Cy < iPr < neopentyl < tBu. The intimate involvement of the carbene pπ-orbital in determining the barrier to reductive elimination means N-substituents that are capable of removing π-density (e.g. phenyl) act to promote a more facile reductive elimination.

Graphical abstract: The influence of N-substitution on the reductive elimination behaviour of hydrocarbyl–palladium–carbene complexes—a DFT study

About
Cited by
Related
Download options Please wait...

Supplementary files

Article information

DOI
https://doi.org/10.1039/B512681A
Article type
Paper
Submitted
07 Sep 2005
Accepted
30 Nov 2005
First published
06 Jan 2006

Dalton Trans., 2006, 1768-1775

Permissions

Request permissions

The influence of N-substitution on the reductive elimination behaviour of hydrocarbyl–palladium–carbene complexes—a DFT study

D. C. Graham, K. J. Cavell and B. F. Yates, Dalton Trans., 2006, 1768 DOI: 10.1039/B512681A

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements