A new spin on catalysis
1 February 2010
A new £489K project funded by EPSRC will help to uncover the importance of electron spins (paramagnetism) in organometallic redox centres, which are used for oligomerisation catalysis.
Chain growth reactions involving alkenes, such as selective ethylene oligomerisation, are extremely important industrial processes; the resulting alpha-olefins are transformed into a range of commodity chemicals from surfactants to polymer additives. Homogeneous catalysts, based on chromium organometallic compounds, are widely used for these oligomerisation reactions. Details of the reaction mechanism are poorly understood, in part due to the complexity of the catalytic system but also because the paramagnetic character of the reaction intermediates has been a barrier to mechanistic studies. However, a greater understanding of the mechanism is vital in order to design the next generation of polymerisation catalysts.
In a collaborative EPSRC funded project (£488,900) involving synthesis and catalysis, (Cavell, Ward) and EPR spectroscopy (Murphy), a comprehensive insight into the oxidation and spin states involved in the catalytic reaction will be developed. Novel ligands based on N-heterocyclic carbenes will be synthesised, and catalytic performance and reaction intermediates formed in the catalytic cycle will be investigated by the groups of Prof Kingsley Cavell and Dr. Ben Ward. Advanced pulsed EPR techniques will be applied by the group of Dr. Damien Murphy, to provide an unsurpassed glimpse into the redox/spin states, ligand structure and electronic properties of the intermediates involved in the catalytic reaction, achieving a depth of understanding not previously attainable.