Background: There is a clear need to develop processes that minimise the consumption of limited energy resources and reduce waste detrimental to the environment. Catalysis plays a central role for reducing waste and energy consumption and is used for the production of ca. 90% of industrial chemicals. Nevertheless, there is significant scope to develop new catalysis and ways to apply energy, such as using sunlight. Oxidation is a fundamental chemical reaction underpinning many processes in nature and industry. In principle, the cleanest source of oxygen atoms are water and dioxygen in air. However, industry often uses peroxides or metal oxides that lead to significant waste, primarily because viable catalytic reactions, which use water or air, are yet to be sufficiently developed.
Objectives: Our goal is to investigate oxygen atom transfer (OAT) using soluble metal complex catalysts activated by light. Preliminary work has shown that OAT is very sensitive to the ligand structure and that light is required for more than one fundamental step in the catalytic cycle. This project would investigate details of the mechanism and explore the scope of the OAT reaction for oxidation of useful substrates using clean oxygen sources.
Experimental Approach: Metal complex synthesis and photocatalysis will be supported by detailed structural and spectroscopic studies to understand the structure-property relationships that determine thermodynamic and kinetic phenomena that control the OAT process. Metal complex synthesis will include ligand development of multidentate ligands with photoactive components and the use of transition metals that can support reactive metal-oxo functionalities. Characterisation will include single-crystal X-ray diffraction, NMR, IR, Raman, UV-vis spectroscopies, mass spectrometry and electrochemistry. The catalytic mechanism will be studied using time-resolved NMR, IR and UV/vis spectroscopy with the potential to use national facilities for ultrafast studies, and product analysis will use a combination of GC and HPLC. In collaboration, mechanistic and photophysical processes will also be studied theoretically using DFT.
Novelty: OAT is a fundamental biological process but has not been exploited for chemical synthesis. Photo-activated OAT would be a significant advance that would have immediate impact and potentially wide application for clean oxidation.
Training: Will include inorganic complex and ligand synthesis, photochemistry, and electrochemistry. Training in separation techniques (for monitoring reactions) such as GC and HPLC will be provided. Many spectroscopic techniques will be used such as NMR, IR, UV-Vis and Raman, including time-resolved methods.
All Chemistry research students have access to our innovative Doctoral Training in Chemistry (iDTC): cohort-based training to support the development of scientific, transferable and employability skills: https://www.york.ac.uk/chemistry/postgraduate/idtc/
The Department of Chemistry holds an Athena SWAN Gold Award and is committed to supporting equality and diversity for all staff and students. The Department strives to provide a working environment which allows all staff and students to contribute fully, to flourish, and to excel: https://www.york.ac.uk/chemistry/ed/
. This PhD project is available to study full-time or part-time (50%).
This PhD will formally start on 1 October 2020. Induction activities will start on 28 September.