Homogeneous Catalysis

We are studying catalysts that will give very high selectivity to desirable products (e.g. equation 1) or will catalyse unknown reactions sometimes by new mechanistic pathways (equation 2)

Equation 1. Regioselective methoxycarbonylation of alkenes	Equation 2. Alkylation of phenol by C-H activation

Figure 1. Continuous flow homogeneous catalysis using supercritical fluid transport

In addition, we have a major programme on new approaches to separating products from the catalyst in homogeneous reactions. This involves the use of biphasic catalysis involving fluorous, aqueous, ionic liquid and supercritical fluid solvents. Continuous flow catalysis is being explored using catalysts immobilised within a reactor dissolved either in an ionic liquid or in the reaction product and transporting the substrates to and products from the ionic liquid dissolved in a supercritical fluid (Figure 1). We are also investigating systems in which the catalyst is dissolved in a thin film of ionic liquid supported on a solid surface whilst the substrates are carried over the catalytic film and the products are removed in supercritical CO₂. These systems are even more efficient than their bulk liquid phase counterparts.

Recent studies have also included additives to aqueous biphasic systems which give rate enhancements of 30 times without catalyst leaching or emulsion formation.

Figure 2 Nanotubes of InN

Materials Chemistry

We have developed new synthetic methods for nanoparticles and nanoparticle dendrimer composites with interesting light emission properties. Very recently we have developed syntheses to core-shell materials with a metallic indium core and an indium nitride shell. (Figure 2).

SELECTED RECENT PUBLICATIONS

1. Highly selective formation of linear esters from terminal and internal alkenes catalysed by palladium complexes of bis-(ditertiarybutylphosphinomethyl)benzene, C. Jimenez Rodriguez, D. F. Foster, G. R. Eastham, and D. J. Cole-Hamilton, Chem. Commun., 2004, 1720
2. Halide free ethylation of phenol by multifunctional catalysis using phosphinite ligands, M. C. Carrión and D. J. Cole-Hamilton, Chem. Commun., 2006, in the press
3. Continuous Flow Hydroformylation of Alkenes in Supercritical Fluid – Ionic Liquid Biphasic Systems, P. B. Webb, M. F. Sellin, T. E. Kunene, S. Williamson, A. M. Z. Slawin and D. J Cole-Hamilton, J. Am. Chem. Soc., 2003, 125, 15577
4. Continuous Flow Homogeneous Catalysis using Supercritical Fluids, P. B. Webb and D. J. Cole-Hamilton, Chem. Commun., 2004, 612
5. Production and luminescent properties of CdSe and CdS nanoparticle-polymer composites, A. V. Firth, S. W. Haggata, P. K. Khanna, S. J. Williams, J. W. Allen, S. W. Magennis, I. D. W. Samuel and D. J. Cole-Hamilton, J. Luminescence, 2004, 109, 163-172