C-H activation via H-atom abstraction (HAT) and subsequent functionalisation

One of the most challenging and potentially rewarding areas of organic chemistry involves selective activation and functionalisation of compounds. In this developing field, most methods deploy metal-based strategies. By contrast, this project will explore organic routes to activation. By starting with neutral organic compounds, one-electron oxidation or one-electron reduction can afford, respectively, radical cations or radical anions. Radical cations are highly successful at hydrogen atom abstraction from C-H bonds. However the selectivities of these processes are in need of development.
Phase 1 of this programme will examine routes to reactive radical cations based on carbon or heteroatoms, and an examination of their selectivities in abstraction of H-atoms, in oxidative electron transfer and in bond formation to other elements. The parameters that will be tuned are steric and electronic. One system has recently been discovered in our research group that shows excellent selectivity.
Phase 2 will examine the reactivity of radical anions. Until now, with rare exceptions, radical anions have been used as electron donors, rather than as reagents that can form bonds. We will vary the structures of radical anions as we investigate the competition between electron transfer and, for example, hydrogen atom abstraction and other bond formations. Appropriate design of the structure of the radical anions should allow the creation of radical anions that have similar degrees of affinity [to radical cations] for bond formation, but which have complementary properties due to their polarisation.
Phase 3 Reactions will initially be conducted in ground state, but more ambitious chemistry can be achieved with more energetic reagents. Accordingly, excited state chemistry will also be explored. To ensure that the new reactions comply with sustainable chemistry, the excitations will be conducted using visible light. To this end, we are now equipped with powerful LED light sources to energise both radical cations and radical anions, as well as precursor oxidants and reductants to their excited states.
Phase 4 Computational chemical calculations can greatly assist progress in chemistry research in the laboratory, and this has always played an important part in research in our group. Accordingly, the student will undertake studies in computational chemistry, initially in the form of a postgraduate credit-bearing course provided at Strathclyde, but the aim will be to escalate this training to examine, explain and predict discoveries in this project. For this reason, my computational collaborator, Prof Tell Tuttle is 2nd academic supervisor on this project. From experience, it is best to undertake this part of the programme after the student has discovered novel aspects of the experimental work that require computation to rationalise them.
Bringing all aspects of the programme together, our aim will be to adapt discoveries to afford catalytic processes.