Porous Organic Crystals: From Prediction to Synthesis and Function

Lead Research Organisation: University of Liverpool
Department Name: Chemistry


The de novo prediction of molecular crystal structures is an unmet challenge that has central and fundamental importance in areas such as pharmaceuticals, biology, and synthetic functional materials. Building on our recent collaboration (Nature, 2011, 474, 367), we will develop crystal structure prediction methods to underpin the discovery of new functional organic materials. Our focus is 'porous organic cages', a sub-class of porous materials in which the UK has an international lead, and their use in selective molecular separations and in ionic conductivity. The programme involves the close integration of leading groups in the areas of computation, synthesis, and specific property measurements. Hence, a wider outcome will be the development of an integrated 'prediction-to-properties' approach that will have broad impact across many classes of materials, as outlined in the EPSRC Grand Challenge, "Directed Assembly of Extended Structures with Targeted Properties".

Planned Impact

The potential impact from this proposal can be divided into 4 main areas:

(1) Knowledge: Computationally-led materials discovery. We will develop the application of de novo structure prediction methods for new functional materials to focus associated synthetic programmes. We propose that the clear demonstration of this integrated methodology will be the primary impact of the proposal, transcending the specific materials targeted here. This is a 10 year+ vision, and we do not expect to solve the whole problem within the timescale of this project. However, both the short-term and longer-term academic and industrial impacts are potentially broad and important.
(2) Economy: New functional materials. We target here the discovery of new functional materials, specifically for applications in molecular separations and ion conduction. There is scope for direct commercial impact, particularly toward the end of the programme, and we have strong mechanisms (outlined below) to maximize the benefit here.
(3) People. There are still relatively few research programmes worldwide where structural prediction and chemical synthesis are imbedded, hand-in-hand, as proposed here. We will create a unique interdisciplinary training environment for the researchers involved that will enhance their future employability prospects.
(4) Society. The functional materials that we will investigate relate to the area of energy and sustainability, which is of strong societal importance.


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Description We are developing new ways to predict crystal structures for porous organic materials, and directed methods for discovering new applications in molecular separations and as ionic conductors.

By combining prediction with experimental measurements on synthetically accessible materials, we can improve our understanding of what makes a material good for separating particular mixtures of molecules, or why it conducts ions rapidly and selectively. With this knowledge, we can then target the synthesis of specific materials for carrying out these functions.

We have successfully developed methods to predict the molecules that form from synthetic precursors. We are currently developing methods to predict the effect of solvent on the crystal structure adopted by organic crystals. We have been successful in discovering materials to separate rare gases from air, separate mixtures of organic molecules, including molecules that only differ in their handedness.

We have synthesised new materials that exhibit proton conductivity comparable to that of the best metal organic frameworks and exceeding that of other organic molecules investigated so far. The materials have been studied experimentally and computationally to rationalise their excellent conductivity properties.
This research funded by this grant has thus far resulted in six high impact publications, which span the areas of developments in predictive methods and measurement of separations by porous organic materials. Further publications on anhydrous proton conductors, and on predicting the effect of solvent during the crystallisation of porous solids are in preparation.

Jelfs, K. E. et al. In silico Design of Supramolecules from Their Precursors: Odd-Even Effects in Cage-Forming Reactions, J. Am. Chem. Soc. (2013) DOI: 10.1021/ja404253j. Chen, L. et al. Separation of rare gases and chiral molecules by selective binding in porous organic cages, Nature Mater. (2014) DOI: 10.1038/nmat4035. Kewley, A. et al. Porous Organic Cages for Gas Chromatography Separations, Chem. Mater. (2015) DOI: 10.1021/acs.chemmater.5b01112. Hasell, T. et al. Porous Organic Cages for Sulfur Hexafluoride Separation, J. Am. Chem. Soc (2016) DOI: 10.1021/jacs.5b11797. Liu, M. et al. Three-dimensional protonic conductivity in porous organic cage solids, Nature Commun. (2016) doi:10.1038/ncomms12750. Pulido A. et. al. Functional materials discovery using energy-structure-function maps, Nature (2017) doi:10.1038/nature2141. Styrene Purification by Guest-Induced Restructuring of Pillar[6]arene, J. Am. Chem. Soc, DOI: 10.1021/jacs.6b13300. Computational modelling of solvent effects in a prolific solvatomorphic porous organic cage, Faraday Discussion, DOI: 10.1039/C8FD00031J.
Exploitation Route Too early to say - though possible/likely that structure prediction tools will be taken up by less specialised groups.
Sectors Chemicals,Energy,Environment

Description Visit by Hiroshi Yamagishi (2017 - 2018) 
Organisation University of Tokyo
Country Japan 
Sector Academic/University 
PI Contribution Worked as a visitor in Prof. A. I. Cooper group on a 6 month placement.
Collaborator Contribution Synthesis and characterisation of crystalline materials, prepared using pyridyl functionalised molecular hosts.
Impact Research projects are still active.
Start Year 2017
Description Formaldehyde is often released as a pollutant from building materials such as paint and plasterboard, as well as many other household products. It is believed to cause various health problems and is classified as a Group 1 human carcinogen by WHO. The current leading technology for removing formaldehyde is activated carbon adsorption, which has low capture capacity and poor selectivity. A new cage molecule solid was designed and synthesised, that act like a 'cage prison' and can capture low concentration pollutants using a combination of chemical and physical adsorption. The patented technology has been proven to efficiently capture the most common indoor air pollutant, formaldehyde, at both high and low levels and even in humid conditions. CageCapture Ltd (CCL, https://cagecapture.com/), co-founded by the inventors, was formed in December 2019 to commercialise this new cage-based material. This technology was awarded the Royal Society of Chemistry's First Prize in their 2016 Emerging Technologies Competition. In 2019, CageCapture Ltd has been awarded a total of £298,754 funding via Innovate UK with matched funding from the University's Enterprise Investment Fund, through the Innovation to Commercialisation of University Research (ICURe) 'follow on funding' competition. The Innovate UK funding will be used to develop an in-house formaldehyde testing facility to validate the new technology and to explore other applications for the new technology including different pollutants. 
Year Established 2019 
Impact To date, CageCapture has demonstrated that the Cage molecule can be formulated into industrially compatible coating processes for existing air filter production lines, providing an immediate performance uplift, with minimal integration. Materials have already been released to early customers as part of market testing. The resultant test data from several leading players in the chemical and filtration sectors has been positive, with strong expressions of interest for Joint Development Programmes and sample requests.
Website https://cagecapture.com/