Dynamically Adaptive Catalytic Capsules on Solid Supports

Lead Research Organisation: University of Cambridge
Department Name: Chemistry

Abstract

The chemist's quest to transform matter has benefitted from tremendous advances in recent years, with new methods and techniques in chemical synthesis appearing at an accelerating pace. The majority of transformations in the synthetic chemist's toolbox require large inputs of energy, organic solvents, and protecting groups that serve as chemical masking tape, fulfilling their purpose and then being discarded. It would be of benefit to reduce the amounts of all three inputs for both ecological and economic reasons.Biological systems carry out chemistry in water efficiently and economically, using assembly lines of enzymes to piece molecules together. Biological receptors and catalysts differ from synthetic versions in that their functions have been honed through the selective pressures of evolution as opposed to design from first principles, allowing their function to be tuned in ways that the cleverest designer might find hard to predict. All living matter bears witness to the incredible chemical and systemic complexity that can be achieved through the 'blind' design of natural selection.The goal of this project is to create a new class of molecular containers capable of evolving to bind different guests with high affinity. This adaptation will find use in the creation of guest-specific sensors and enzyme-like catalysts, as cages are tailor-made to lower the activation energy for specific reactions. The ability to quickly make designer catalysts for different reactions, coupled with the ability to operate in water, could render these catalytic capsules industrially useful as green nano-reactors. Immobilisation of templated capsules on solid supports will allow for the creation of flow reactors (nano assembly lines) and sensors tailored to specific substrates and analytes.

Planned Impact

Beyond the academic community, we have identified the following groups of stakeholder beneficiaries of this work: Industry: A key aim of the proposed project is to develop a methodology for the generation of a new type of catalytic system capable of addressing key problems encountered by current products and bring a new platform for green and recyclable catalysts to the chemical industry, one of the largest manufacturing industries in the UK. These receptors and catalysts would work in water, and potentially lead to the development and adaptation of processes that lead to less organic solvent and energy use and thus to a lower carbon footprint. General public: Appreciation and public support for scientific progress have underpinned technological progress in the UK ever since the practice of science became professionalised in the 19th century. We are committed to maintaining our side of this dialogue through explaining to the public what we do and why. One mechanism for this is press coverage of our research programme. Our recent Science paper generated a dozen stories in newspapers, TV, and radio across more than five countries, all with a positive bent. Another public benefit arises from synergies between this research project and an ongoing project in the group that is carried out under the auspices of the Home Office - Counter Terrorism and Intelligence Directorate, in which cage compounds will trap and render harmless chemical warfare agents (CWAs). The development of templated cages that are capable of catalytically destroying CWAs could save the lives of members of the public. Likewise, sensors built from dynamically-templated cages will be targeted to sense explosive molecules favoured by terrorists, such as TATP, which are currently difficult to detect. Museums and Conservation: Positive overlaps and synergies are foreseen between this project and a separate project in the group, undertaken in collaboration with Dr Mark Jones, head of conservation at the Mary Rose Trust in Portsmouth. We are investigating new means to preserve and strengthen waterlogged wood artefacts through the dynamic construction of cross-linked polymeric materials within the pores of these artefacts. Sensors developed in the present project could be employed to diagnose different decay processes by sensing their by-products, allowing treatments to be tailored to individual artefacts. What will be done to ensure that they benefit from this research? Industry: We have already entered into discussion with Cambridge Enterprise, the University's technology transfer office regarding IP protection issuing from the cages that we have already prepared. We will continue these discussions, meeting as required over the life of the project to make sure that relevant IP is patented, potential licensees are recognised, and that possibilities for launching spin-outs are also properly identified. Communications and engagement: Impacts will be realised internationally through a wide spectrum of activities; by public outreach through our established relationships with the media and museums, by lectures and displays to specialists and the general public during conferences and symposia, through our web site and the web sites of our collaborators, and by press releases through the University's Office of Communications. Our strategy for publication has proven amenable to media engagement - three of our recent publications have been picked up and highlighted by the broader media. The PI and all members of the research group participate in the annual Cambridge Science Festival to present posters, deliver public lectures, and organise hands-on scientific activities and demonstrations. We will use cartoon schemes to help introduce the general public to the basic concepts of chemical self-assembly, whose aesthetic appeal can readily be appreciated by the general public. This could help inspire young people to pursue careers in science.

Publications

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Bilbeisi RA (2013) Guest binding subtly influences spin crossover in an FeII4L4 capsule. in Chemistry (Weinheim an der Bergstrasse, Germany)

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Bilbeisi RA (2013) A self-assembled [Fe(II)12L12] capsule with an icosahedral framework. in Angewandte Chemie (International ed. in English)

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Black SP (2013) Generation of a dynamic system of three-dimensional tetrahedral polycatenanes. in Angewandte Chemie (International ed. in English)

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Browne C (2015) Carbon dioxide fixation and sulfate sequestration by a supramolecular trigonal bipyramid. in Angewandte Chemie (International ed. in English)

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Gan Q (2015) Cooperative loading and release behavior of a metal-organic receptor. in Journal of the American Chemical Society

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Jayamurugan G (2015) Selective endo and exo binding of mono- and ditopic ligands to a rhomboidal diporphyrin prism. in Angewandte Chemie (International ed. in English)

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Ma S (2013) Chain-reaction anion exchange between metal-organic cages. in Journal of the American Chemical Society

 
Description How to make hollow encapsulant molecules with the ability to bind a wide variety of smaller 'guest' molecules, selectively.
Exploitation Route Our new encapsulants show promise in transforming their guests, protecting them (under different circumstances), or transporting them.
Sectors Aerospace, Defence and Marine,Chemicals,Creative Economy,Manufacturing, including Industrial Biotechology

URL http://www-jrn.ch.cam.ac.uk/
 
Description My group's research has explored the preparation of complex, functional structures using chemical self-assembly. A signature feature of our approach is the simultaneous use of different kinds of chemical-bond-forming reactions that operate under thermodynamic control to bring about a substantial increase in structural complexity during a single overall process. I have coined the term 'subcomponent self-assembly' to describe this technique; other research groups worldwide have fruitfully adopted this method and terminology, citing my group's work at the source. Building upon the self-assembly rules that we deciphered, we were able to design a capsule that is capable of binding white phosphorus (P4) within its central hollow (Science 2009, 324, 1697). White phosphorus, which has been known for centuries to catch fire upon contact with atmospheric oxygen, was thus rendered indefinitely air-stable through encapsulation. Our dramatic pacification of this ancient demon attracted substantial media interest, and is discussed in an undergraduate chemistry textbook (Chemistry: The Molecular Science, 4th ed, C. L. Stanitski, P.C. Jurs, M. Sanger, Brooks/Cole, Stamford CT USA, 2011; p. 1024). When collections of subcomponent building blocks come together to form multiple products, reaction patterns can become quite complex. Such mixtures are best considered as molecular networks or systems, in which the introduction of a new subcomponent may have consequences involving many molecules. Understanding signal transduction within such abiological systems may help to illuminate the behaviour of more complex biochemical networks. The originality and impact of our contributions in this area have been recognised by an invitation to write a Q&A piece (Nature 2009, 460, 15) on systems chemistry, an emerging field which I am helping to define. A new line of research for my group has involved the preparation of metal-containing conjugated polymers through the use of our techniques (J. Am. Chem. Soc. 2011, 133, 3158). These polymers have been built into electroluminescent devices with the group of Richard Friend in Physics (J. Am. Chem. Soc. 2012, 135, 19170), and sensors able to determine the handedness of molecules in solution in collaboration with Milko van der Boom's group at the Weizmann Institute (J. Am. Chem. Soc. 2013, 135, in press: dx.doi.org/10.1021/ja4077205). This work is demonstrating the utility of our techniques to solve real-world problems, with the creation of economic value as our next goal. A key future direction to my group's effort will be the design and exploration of chemical systems that are capable of evolution towards the achievement of a targeted function, such as electrical conductivity for a polymer or the fit of a capsule to a guest molecule.
First Year Of Impact 2009
Sector Aerospace, Defence and Marine,Chemicals,Creative Economy,Education,Culture, Heritage, Museums and Collections
Impact Types Cultural,Societal,Economic

 
Description EPSRC Dynamically Adaptive Metal-organic Nanopores
Amount £301,303 (GBP)
Funding ID 75639 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 01/2015 
End 03/2018
 
Description EPSRC Iminoboronate Polymers as Dynamically Adaptable, Photoactive Materials
Amount £762,618 (GBP)
Funding ID 76030 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 01/2015 
End 12/2017
 
Description Pint of Science, Cambridge Science Festival 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? Yes
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact To provide a platform which allows people to discuss research with the people who carry it out.

Inspired the public.
Year(s) Of Engagement Activity 2014