Professor of Inorganic Chemistry

B.Sc., Ph.D. (Southampton).

Tel: 0116 2522108

email egh1@le.ac.uk

Research Interests

Low Valent Transition Metal Fluorides

Although classically viewed as a ligand for high oxidation state metal systems, there is worldwide interest in exploiting the unique properties of fluoride in low valent metal chemistry. Early work in Leicester focussed on carbonyl-fluoride complexes of rhenium, osmium, iridium and ruthenium, and recent highlights include novel chemistry in metal-fluoride-phosphine1 and metal-fluoride-NHC systems2 (Figure 1), including cyclometallation at the metal centre (via HF elimination; Figure 2) and the first rhodium(III) difluoride coordination complexes.

Figure 2 Bis-cyclometallation in a Ru(II) – NHC complex.

Coordination Chemistry of Fluorinated Ligands

A strong theme for the Leicester Fluorine group over many years has been the investigation and exploitation of the unique influence of fluorine substitution on ligand properties in transition metal coordination chemisty. Recent highlights include:

• The definitive evaluation of the effect of fluoroalkylation on the electronic properties of phosphines (Figure 3).³

• The coordination chemistry of fluorinated and fluoroalkylated dithiophosphate, phosphonate (Figure 4),⁴ α-diimine and N-heterocyclic carbene ligand systems.

Figure 4 Pt(II) complex of a perfluoroalkylated phosphonite ligand.

Fluorous approaches to Catalysis

We have exploited our synthetic expertise in fluorinated ligand chemistry for applications to product separation issues in catalytic systems. Building on the work on fluorous biphase systems we have:-

• developed a unique set of ligand-catalyst-solvent-equipment systems, in collaboration with groups in St Andrews and UCL, for the continuous hydroformylation of n-octene with both excellent selectivity and catalyst recovery (Figure 5).⁵

• exploited the fluorinated ligands, in collaboration with Liverpool University, for asymmetric catalysis in scCO₂.⁶

• established the first recovery and recycle of a metal catalyst using fluorous solid phase extraction.⁷

• developed novel fluorous solid phase supports, based on polystyrene (Figure 6) and α-zirconium phosphonate backbones, specifically for fluorous solid phase extraction of sensitive metal catalysts.

  

Selected Publications

1. D. A. J. Harding, E. G. Hope, J. Fawcett and G. A. Solan, J. Organomet. Chem., (2007), 692, 5474-5480.
2. D. A. J. Harding, E. G. Hope, J. Fawcett and G. A. Solan, Dalton Trans., (2009), 6861-6870.
3. D. J. Adams, J. A. Bennett,D. Duncan, E. G. Hope, J. Hopewell  and A. M. Stuart, Polyhedron., (2007), 26, 15050-1513.
4. J. A. Bennett, E. G. Hope, A. M. Stuart and K. Singh, J. Fluorine Chem., (2009), 130, 615-620 
5. E. Perperi, Y. Huang, P. Angeli, G. Manos, C. R. Mathison, D. J. Cole-Hamilton, D. J. Adams and E. G. Hope, Dalton Trans., (2004), 2062-2064.
6. Y. Hu, D. J. Birdsall, A. M. Stuart, E. G. Hope and J. Xiao, J. Mol. Cat. A.,(2004), 219, 57-60.
7.  B. Croxtall, E. G. Hope and A. M. Stuart, Chem. Commun., (2003), 2430-2431.