Issue 24, 2016

Solvent influence on the thermodynamics for hydride transfer from bis(diphosphine) complexes of nickel

Abstract

The thermodynamic hydricity of a metal hydride can vary considerably between solvents. This parameter can be used to determine the favourability of a hydride-transfer reaction, such as the reaction between a metal hydride and CO2 to produce formate. Because the hydricities of these species do not vary consistently between solvents, reactions that are thermodynamically unfavourable in one solvent can be favourable in others. The hydricity of a water-soluble, bis-phosphine nickel hydride complex was compared to the hydricity of formate in water and in acetonitrile. Formate is a better hydride donor than [HNi(dmpe)2]+ by 7 kcal mol−1 in acetonitrile, and no hydride transfer from [HNi(dmpe)2]+ to CO2 occurs in this solvent. The hydricity of [HNi(dmpe)2]+ is greatly improved in water relative to acetonitrile, in that reduction of CO2 to formate by [HNi(dmpe)2]+ was found to be thermodynamically downhill by 8 kcal mol−1. Catalysis for the hydrogenation of CO2 was pursued, but the regeneration of [HNi(dmpe)2] under catalytic conditions was unfavourable. However, the present results demonstrate that the solvent dependence of thermodynamic parameters such as hydricity and acidity can be exploited in order to produce systems with balanced or favourable overall thermodynamics. This approach should be advantageous for the design of future water-soluble catalysts.

Graphical abstract: Solvent influence on the thermodynamics for hydride transfer from bis(diphosphine) complexes of nickel

Supplementary files

Article information

Article type
Paper
Submitted
22 Jan 2016
Accepted
01 Eph 2016
First published
12 Eph 2016

Dalton Trans., 2016,45, 10017-10023

Solvent influence on the thermodynamics for hydride transfer from bis(diphosphine) complexes of nickel

S. J. Connelly Robinson, C. M. Zall, D. L. Miller, J. C. Linehan and A. M. Appel, Dalton Trans., 2016, 45, 10017 DOI: 10.1039/C6DT00309E

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