Stimuli Responsive Catalysis

Stimuli-responsive catalysis has had a considerable impact on catalyst reusability and recyclability through combining the reactivity of homogenous catalysis with the ease of recovery of heterogeneous catalysis. This has primarily been achieved through the development of thermo- or pH-reponsive polymer- or gel-based catalytic systems as recyclable catalysts for organic synthesis. However, examples of controlling catalytic activity through stimuli other than pH or temperature, are lacking by comparison. Recently a pro-ligand approach has been developed to activate metal complexes to carry out selective synthetic transformations only in the presence of specific enzymes (Chem. Sci., 2015, 6, 4978-4985.).
The challenges are inter-disciplinary and focus on developing fundamental new science in stimuli-responsive catalysis. Specifically, each new target-configured reagent system requires: (a) Stable latent catalyst; (b) Biocompatible conditions; (c) Fast, selective and irreversible activation; (d) Well understood mechanism of activation; (e) No activation by impurities; (f) Low background reaction; (g) Fast, selective functional group transformation. To address these challenges the project will focus on the three principal elements of recognition, activation and response. There are opportunities for the student to direct the project into the research areas that interest them the most - this a concept driven project that could find application in chemical diagnostics, the repair or recycling of materials or drug discovery. A particularly ambitious approach would be to develop two enantiomeric complexes that could be selectively activated to synthesise either enantiomer of a desired product (e.g. amino acid). As enantiomeric compounds are known to often have very different biological properties this could be the basis of a smart catalyst system that could make a specific drug in the presence of one enzyme (stimulus) and another in the presence of a different enzyme.
The preliminary communication of this concept was submitted to Nature Chemistry and was selected to go out to referee but narrowly rejected. Our publication strategy is therefore to remain ambitious, we have confidence that this project area is of interest to a broad range of scientists and will pass editorial review at the highest level: Nature, Science and J. Am. Chem. Soc. It is clear that this concept could form the basis of a competitive grant application to EPSRC responsive mode and this will be pursued whilst continuing to build a critical mass of preliminary results and publications.