X-ray photoelectron spectroscopy as a probe of rhodium-ligand interaction in ionic liquids

Men, Shuan and Lovelock, Kevin and Licence, Peter (2016) X-ray photoelectron spectroscopy as a probe of rhodium-ligand interaction in ionic liquids. Chemical Physics Letters (645). pp. 53-58. ISSN 0009-2614

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Abstract

We use X-ray photoelectron spectroscopy (XPS) to identify the interaction between the rhodium atom and phosphine ligands in six 1-octyl-3-methylimidazolium-based ionic liquids ([C8C1Im][X]). The formation of a mono-phosphine rhodium complex based upon addition of triphenylphosphine (PPh3) is confirmed by XPS in all ionic liquids studied herein. Due to the electron donation effect of the ligand, the rhodium atom becomes more negatively charged and thus exhibits a lower measured binding energy. The influence of the anion basicity on the formation of different types of rhodium complexes is also investigated. By introducing a biphosphine ligand, a chelated diphosphine rhodium complex is formed in ionic liquids with more basic anions and verified by both XPS and Infrared Spectroscopy (IR). The measured Rh 3d binding energies are correlated to the reaction selectivity of a hydroformylation reaction which inspires a method to design a metal catalyst to control the chemical reaction towards desired products in the future.

Item Type: Article
Keywords: Ionic liquids, Phosphine ligands, Rhodium atom, Biphosphine ligand, Chelated diphosphine rhodium complex
Schools/Departments: University of Nottingham, UK > Faculty of Science > School of Chemistry
Identification Number: 10.1016/j.cplett.2015.12.017
Depositing User: Licence, Peter
Date Deposited: 07 Sep 2017 12:25
Last Modified: 16 Nov 2017 17:47
URI: http://eprints.nottingham.ac.uk/id/eprint/45497

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