Hydrocarbon activation by f-block complexes

Burning petrol and other hydrocarbons from fossil fuels is damaging to the environment and wasteful of resources that could otherwise be used to make substances that improve the quality of life. However, the strength of the carbon-hydrogen bond, coupled with the difficulties associated with selectively accessing a specific site on a particular molecule, means that highly reactive metal compounds are needed to catalyse such processes.A single C-H bond in methane, the simplest and most abundant hydrocarbon, is potentially the most financially important target for selective functionalisation, but the activation of C-H bonds in more complex hydrocarbons is also a highly desirable 'toolbox' component for scientists working in all areas of chemical synthesis. This selectivity will become increasingly more important as our palette of platform chemicals changes from fossil fuel-derived to biomass-derived in the coming years.Organometallic compounds of the lanthanides and actinides first gave a tantalising glimpse of their potential with the selective cleavage of one C-H bond in methane some 25 years ago, but the limitations of the supporting ligands precluded any further functionalisation step. Since then, a variety of C-H bond activation chemistry has been demonstrated at d- and f-block metal centres that has increased our fundamental understanding of this reaction, but not yet provided profitable applications. Recent advances in organometallic f-block chemistry (both in terms of academic breakthroughs, and characterisation methods), and the desire to find C-H activation catalysts not based on the rare and expensive platinum group metals, is now pushing f-block metals back to the forefront of C-H bond activation chemistry.We have made a variety of contributions to organometallic f-block chemistry that challenge traditional views of f-block structure and bonding, such as the isolation of f-block complexes with new polar metal-element bonds (J. Am. Chem. Soc. 2007), and the demonstration of unprecedented reactivity of the U=O oxo groups of the uranyl dication towards C-Si and N-Si bond cleavage (Nature, 2008).The proposed programme of work focuses on the selective activation and functionalisation of hydrocarbon C-H bonds, and builds on our recent successes and proof-of-concept results in functional organolanthanide and actinide chemistry. We have identified three mechanistically distinct types of C-H bond activation, and have combined them into one programme, to offer the highest chance of success. A fellowship offers the ideal opportunity for the PI to manage this intensive and internationally collaborative research programme and deliver new f-block catalysts for hydrocarbon activation.This work contributes to the Energy priority, by providing catalytic, atom-efficient, low-energy chemical routes to convert hydrocarbons from biomass or fossil fuels into high-value chemicals, so benefitting both industry and society.The fundamental understanding that comes from the reactivity and bonding studies of unusual f-block compounds improves our ability to handle nuclear materials and wastes, while the researchers on this project will gain actinide handling skills that are identified as a key shortage in the UK. Finally, the demonstration of important hydrocarbon chemistry by depleted uranium compounds would help to enhance the public image of uranium in our future nuclear age.