Sep 262020
Howard Flack and the Flack Parameter (D.J. Watkin & R.I. Cooper)

Chemistry 2020, 2(4), 796-804; DOI: 10.3390/chemistry2040052

The Flack Parameter is now almost universally reported for all chiral materials characterized by X-ray crystallography. Its elegant simplicity was an inspired development by Howard Flack, and although the original algorithm for its computation has been strengthened by other workers, it remains an essential outcome for any … Read the rest

Mar 122020
Increasing the performance, trustworthiness and practical value of machine learning models: a case study predicting hydrogen bond network dimensionalities from molecular diagrams (A.P. Frade, P. McCabe & R.I. Cooper)

CrystEngComm, 2020, DOI: 10.1039/D0CE00111B

The performance of a model is dependent on the quality and information content of the data used to build it. By applying machine learning approaches to a standard chemical dataset, we developed a 4-class classification algorithm that is able to predict the hydrogen bond network dimensionality that a molecule would … Read the rest

Oct 172019
A hexagonal planar transition-metal complex (M. Garçon, C. Bakewell, G. A. Sackman, A. J. P. White, R. I. Cooper, A. J. Edwards & M. R. Crimmin)

Nature 574, 390–393 (2019). [ doi: 10.1038/s41586-019-1616-2 ]

We report the isolation and structural characterization of a simple coordination complex in which six ligands form bonds with a central transition metal in a hexagonal planar arrangement. The structure contains a central palladium atom surrounded by three hydride and three magnesium-based ligands. This finding has … Read the rest

Aug 302018
Unexpected Behaviour in Derivatives of Barluenga's Reagent (L. C. F. Morgan, Y. Kim, J. N. Blandy, C. A. Murray, K. E. Christensen & A. L. Thompson)

Chemical Communications 2018, 54, 9849 – 9852 [doi:10.1039/C8CC05430D]

For the collidine analogues of Barluenga’s Reagent (IPy2BF4) reported, a flat cation is necessary for the generation of a modulated phase, in keeping with the “Ratchet Model” theory [Kim et al., Crystal Growth & Design, 2014, Read the rest

Aug 292018
ECM31, Oviedo and ECA Crystallographic Computing School, Mieres

The 31st European Crystallography Meeting was held in Oviedo, Spain from 22-26 August 2018.

During the meeting George Sackman presented a poster (MS10-P05) on recent neutron diffraction work with Richard Cooper and Alison EdwardsDisordered or not: A cautionary tale when inferring proton disorder solely from X-ray and computational data.

Richard Cooper gave a … Read the rest

Jun 242018
An enhanced set of displacement parameter restraints in CRYSTALS (P. Parois, J. Arnold and R.I. Cooper)

Journal of Applied Crystallography, 2018, 51, 1059-1068. [ doi: 10.1107/S1600576718007100 ]

The implementation and use of a set of new displacement parameter restraints is described. Anisotropic displacement parameters account for a large proportion of the parameters in a crystallographic refinement, but very few restraints for conveniently controlling their values have been implemented in … Read the rest

Apr 052018
Prizes at the BCA Spring Meeting 2018 in Warwick

The 2018 Meeting of the British Crystallographic Association was held at Warwick University where Chem. Cryst. was well represented.  The meeting started with the Young Crystallographers Satellite meeting, during which Lewis Morgan’s oral presentation was so “eggsellent” that he won the Industrial Group Prize for the best talk, and with it, the dubious honour of … Read the rest

Nov 012017
Some Experimental Aspects of Absolute Configuration Determination using Single Crystal X-​Ray Diffraction (A. L. Thompson, S. F. Jenkinson & G. W. J. Fleet)

Tetrahedron Asymmetry 2017, 28(10), 1330-1336 [doi:10.1016/j.tetasy.2017.08.016]

Students of single crystal X-​ray diffraction are often give advice as to how best to collect their data when attempting absolute configuration determination.  These ‘rules’ often have more grounding in gut-​feeling than evidence.  Thus, in an effort to provide advice and evidence that today’s crystallographers can … Read the rest

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