Issue 12, 2016

Dioxygen insertion into the gold(i)–hydride bond: spin orbit coupling effects in the spotlight for oxidative addition

Abstract

O2 insertion into a Au(I)–H bond occurs through an oxidative addition/recombination mechanism, showing peculiar differences with respect to Pd(II)–H, for which O2 insertion takes place through a hydrogen abstraction mechanism in the triplet potential energy surface with a pure spin transition state. We demonstrate that the spin-forbidden Au(I)–hydride O2 insertion reaction can only be described accurately by inclusion of spin orbit coupling (SOC) effects. We further find that a new mechanism involving two O2 molecules is also feasible, and this result, together with the unexpectedly high experimental entropic activation parameter, suggests the possibility that a third species could be involved in the rate determining step of the reaction. Finally, we show that the O2 oxidative addition into a Au(I)–alkyl (CH3) bond also occurs but the following recombination process using O2 is unfeasible and the metastable intermediate Au(III) species will revert to reactants, thus accounting for the experimental inertness of Au–alkyl complexes toward oxygen, as frequently observed in catalytic applications. We believe that this study can pave the way for further theoretical and experimental investigations in the field of Au(I)/Au(III) oxidation reactions, including ligand, additive and solvent effects.

Graphical abstract: Dioxygen insertion into the gold(i)–hydride bond: spin orbit coupling effects in the spotlight for oxidative addition

Supplementary files

Article information

Article type
Edge Article
Submitted
16 May 2016
Accepted
22 Jul 2016
First published
25 Jul 2016
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2016,7, 7034-7039

Dioxygen insertion into the gold(I)–hydride bond: spin orbit coupling effects in the spotlight for oxidative addition

C. A. Gaggioli, L. Belpassi, F. Tarantelli, D. Zuccaccia, J. N. Harvey and P. Belanzoni, Chem. Sci., 2016, 7, 7034 DOI: 10.1039/C6SC02161A

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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