Stimuli Responsive Catalysis

Lead Research Organisation: University of Bath
Department Name: Chemistry


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.


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Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/N509589/1 01/10/2016 30/09/2021
1789861 Studentship EP/N509589/1 01/10/2016 31/03/2020 Sam Spring
Description A new strategy has been developed for the detection of beta-galatcosidase, an enzyme commonly used to detect E. coli, in aqueous environments. An electrochemical substrate was successfully designed, synthesised and shown to be an rapid and reliable sensor for beta galactosidase.

A novel electrochemical sensor was developed for the detection of organophosphorus(III) compounds including a nerve agent precursor. It was shown to detect a model analyte down to 12 ppm, the LD50 for rats. Further studies showed the ability for detection of phosphines in complex samples, enabling the detection of impurities in pharmaceutical products.

A stimuli responsive asymmetric catalytic system has been developed. The system combines three reactions into a complex mixture that can be used to control the enantioselectivity of the reaction depending on an external stimulus.
Exploitation Route The beta-galactosidase sensor has potential for incorporation into a water quality tool kit. The ability to detect E. coli in waste water is of high interest in the developing world.
The organophosphorus(III) assay has potential to be incorporate into a handheld detector for nerve agent precursors, or for use in the pharmaceutical industry to detect potential impurities in reactions.
Sectors Environment,Healthcare,Pharmaceuticals and Medical Biotechnology