Oct 232017
 
HUG and SQUEEZE: using CRYSTALS to incorporate resonant-scattering in the SQUEEZE structure factor contributions to determine absolute structure (R.I. Cooper, H.D. Flack and D.J. Watkin)Acta Crystallographica, 2017, C73, 845–853. [ doi:10.1107/S2053229617013304 ] Using an approximate correction to the X-ray scattering from disordered, resonantly scattering regions of crystal structures we have developed and tested a procedure (HUG) to recover the absolute structure using conventional Flack x refi nement or other post-re finement determination methods.
Sep 082017
 
IUCr 2017

The triennial congress of the International Union of Crystallography was held in Hyderabad over 8 days in August 2017.

During the meeting Richard Cooper presented recent work with Jerome Wicker:
Optimizing co-crystal  screens using a data-driven machine learning method

We also took an opportunity to present recent developments in the CRYSTALS software at the … Read the rest

Jul 062017
 
Will They Co-crystallize? (J.G.P. Wicker,  L.M. Crowley,  O. Robshaw,  E.J. Little,  S. Stokes,  R.I. Cooper  and  S.E. Lawrence)

CrystEngComm, 2017, 19, 5336 – 5340 [ doi:10.1039/C7CE00587C ]

A data-driven approach to predicting co-crystal formation reduces the number of experiments required to successfully produce new co-crystals. A machine learning algorithm trained on an in-house set of co-crystallization experiments results in a 2.6-fold enrichment of successful co-crystal formation in a ranked list of … Read the rest

Jun 202017
 
A publicly available crystallisation data set and its application in machine learning (M. Pillong, C. Marx, P. Piechon, J.G.P. Wicker, R.I. Cooper and T. Wagner)

CrystEngComm, 2017,19, 3737-3745 [ doi:10.1039/C7CE00738H ]

We present here the crystallisation outcomes for 319 publicly available compounds in up to 18 different solvents spread over 5710 individual single solvent evaporation trials. The recorded data is part of a much larger, corresponding in-house database and includes both positive as well as negative crystallisation … Read the rest

Apr 202017
 
BCA Poster Prizes for Laura and James

Congratulations to Part II students Laura Fenwick and James Walker who both won poster prizes awarded by the Chemical Crystallography Group of the British Crystallographic Association at the Annual Spring Meeting in Lancaster.

Laura’s poster “Measuring and controlling dissolution rates of pharmaceutical materials by co-crystal formation” reported dissolution rate studies of tablets of pure paracetamol … Read the rest

Nov 242016
 
Beyond Rotatable Bond Counts: Capturing 3D Conformational Flexibility in a Single Descriptor (J.G.P. Wicker and R.I. Cooper)J. Chem. Inf. Model., 2016, 56 (12), 2347–2352 doi: 10.1021/acs.jcim.6b00565 A new molecular descriptor, nConf20, based on chemical connectivity, is presented which captures the accessible conformational space of a molecule. Currently the best available 2-dimensional descriptors for quantifying the flexibility of a particular molecule are the rotatable bond count (RBC) and the Kier flexibility index.
Sep 192016
 
Why direct and post-refinement determinations of absolute structure may give different results (D.J. Watkin and R.I. Cooper)

Acta. Cryst. (2016) B72 661-683 (Feature Article) [ doi:10.1107/S2052520616012890 ]

Direct determination of the Flack parameter as part of the structure refinement procedure usually gives different, though similar, values to post-refinement methods. The source of this discrepancy has been probed by analysing a range of data sets taken from the recent literature. Most significantly, … Read the rest

Aug 022016
 
Report on the sixth blind test of organic crystal structure prediction methods (A. M. Reilly, R. I. Cooper, C. S. Adjiman, S. Bhattacharya, A. D. Boese ...

Acta. Cryst. (2016) B72(4), 439-459 [ doi:10.1107/S2052520616007447 ] A. M. Reilly, R. I. Cooper, C. S. Adjiman, S. Bhattacharya, A. D. Boese, J. G. Brandenburg, P. J. Bygrave, R. Bylsma, J. E. Campbell, R. Car, D. H. Case, R. Chadha, J. C. Cole, K. Cosburn, H. M. Cuppen, F. Curtis, G. M. Day, … Read the rest

Apr 082016
 
2016 British Crystallographic Association Meeting

The 2016 British Crystallographic Meeting Spring Meeting took place at the University of Nottingham from 4th – 7th April. Contributions from Chem. Cryst. staff and students were:

Jerome G. P. Wicker, Bill I. F. David & Richard I. Cooper
When will it Crystallise? (Talk in session: From Amorphous to Crystal)

Jo Baker & Richard … Read the rest