Control and Prediction of the Organic Solid State
Crystal Structure Prediction of organic molecules
The programme for the 2012 CPOSS Meeting is now available, and registration is open
Developed as a complement to experimental solid state screening
There is a general video introduction to the project for those without the scientific background, or the overview for those with a greater understanding of our work.
Developing a computational technology for the prediction of organic crystal structures by contrasting the prediction with extensive experimental studies was the aim of the original CPOSS project (2003-8) funded by the Basic Technology program of the Research Councils UK. During this project we developed our unique automated medium- throughput crystallisation system and by a range of developing multi-disciplinary experimental and computational collaborations (l3) were able to rationalise the solid state diversity of many systems in terms of the structures on the computed crystal energy landscape. We developed DMACRYS and the use of a suite of other programs to calculate the structures, energies, spectroscopic, mechanical and morphological properties of the thermodynamically feasible crystal structures. These energy landscapes for over a hundred molecules are now in the CPOSS database.
Our publications show how computed crystal energy landscapes can be used to
- Predict crystal structures, for the design of new organic materials
- Confirm that the most stable crystal structure has been obtained.
- Suggest structures for possible polymorphs to aid design to crystallisation techniques to target these polymorphs
- Aid structure solution from powder diffraction data
- Suggest possible forms of disorder
- Aid understanding of crystallisation behaviour.
We are now in a translation stage with limited funding from the Basic Technology Programme to work with members of the CPOSS Industrial Alliance and a range of academic groups to develop the use of the computational and polymorph screening and characterisation techniques in inter-disciplinary collaborations. We organise annual meetings as a networking event for the UK organic solid state community, and look forward to contributing to the Grand Challenge of Directed Assembly of Extended Structures with Targeted Properties.
Example of crystal energy landscape predicting disorder and complex crystallisation behaviour
At first glance, the two hypothetical structures of eniluracil (above) look the same, but actually they are two of several almost equi-energtic structures, with very similar powder patterns, that have distinct relative positions of an oxygen (red) and hydrogen (white) atoms, resulting in either a polar ribbon (right) or non-polar ribbon (left). This rationalises the variable disorder found in single crystals of eniluracil and a long history of problems in charaterising the structure and producing a robust crystallisation procedure. |
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