May 302015
 
Crystal structures of increasingly large molecules: meeting the challenges with CRYSTALS software (P. Parois, R.I. Cooper & A.L. Thompson)

Chemistry Central Journal 2015, 9:30 [ doi:10.1186/s13065-015-0105-4 ]

The size and complexity of molecules being studied by single crystal diffraction is growing year by year, resulting in an increase in the difficulties encountered during structure determination. From the crystallisation itself and sample handling, to structure solution and refinement, specific problems due to larger molecules … Read the rest

Feb 032015
 
Annotated article on RSC Learn Chemistry site

Annotated articles are based on research from a range of Royal Society of Chemistry journals that has been re-written into a standard, accessible format.

An annotated article on predicting and controlling the crystallinity of molecular materials by Jerome Wicker and Richard Cooper aims to help readers to understand the research the journal article is based … Read the rest

Nov 042014
 
Will it crystallise? Predicting crystallinity of molecular materials (J.G.P. Wicker and R.I. Cooper)

CrystEngComm (2015) 17, 1927-1934 [ doi:10.1039/C4CE01912A ]

Machine learning algorithms can be used to create models which separate molecular materials which will form good-quality crystals from those that will not, and predict how synthetic modifications will change the crystallinity.

Chemistry World Article: Will It Crystallise

Publisher’s copy

 

Oct 302014
 
Toward the Understanding of Modulation in Molecular Materials: Barluenga's Reagent and its Analogues (Y. Kim, E.J. Mckinley, K.E. Christensen, N.H. Rees, and A.L. Thompson)

Crystal Growth & Design (2014). 14 (12), 6294–6301. [ doi:10.1021/cg500983s ]

Investigations into the phase transition of Barluenga’s reagent revealed a transient incommensurately modulated phase. To understand the origin of the modulated phase and the chemistry that can affect it, analogues of Barluenga’s reagent were synthesized and studied. In this context, the halogen and anion … Read the rest

Dec 202012
 
DetOx: A Program for Determining Anomalous Scattering Factors of Mixed-Oxidation-State Species (K.J. Sutton, S.A. Barnett, K.E. Christensen, H. Nowell, A.L. Thompson, D.R. Allan and R.I. Cooper)

J. Sync. Rad (2013). 20, 200–204. [ doi:10.1107/S0909049512044007 ]

Overlapping absorption edges will occur when an element is present in multiple oxidation states within a material. DetOx is a program for partitioning overlapping X-ray absorption spectra into contributions from individual atomic species and computing the dependence of the anomalous scattering factors on X-ray energy. … Read the rest

Sep 212012
 
CRYSTALS Enhancements: Asymmetric Restraints (R. I. Cooper, A. Thorn and D. J. Watkin)

J. Appl. Cryst. (2012). 45, 1057–1060. [ doi:10.1107/S0021889812035790 ]

The traditional Waser distance restraint, the rigid-bond restraint and atomic displacement parameter (ADP) similarity restraints have an equal influence on both atoms involved in the restraint. This may be inappropriate in cases where it can reasonably be expected that the precision of the determination of … Read the rest

Apr 302012
 
Applications of Leverage Analysis in Structure Refinement (S. Parsons, T. Wagner, O. Presly, P. A. Wood and R. I. Cooper)

J Appl. Cryst. (2012), 45, 417-429. [ doi:10.1107/S0021889812015191 ]

Leverages measure the influence that observations (intensity data and restraints) have on the fit obtained in crystal structure refinement. Further analysis enables the influence that observations have on specific parameters to be measured. The results of leverage analyses are discussed in the context of the … Read the rest

Mar 192012
 
Alkyl-chain Disorder in Tetraisohexylammonium Bromide (M. A. Kelland and A. L. Thompson)

Acta Cryst.  (2012), C68, o152-o155.    [ doi:10.1107/S0108270112009377 ]

Tetraisohexylammonium bromide [systematic name: tetrakis(4-methylpentyl)azanium bromide], C24H52N+·Br, is a powerful structure II clathrate hydrate crystal-growth inhibitor. The crystal structure, in the space group P3221, contains one ammonium cation and one bromide anion in the asymmetric unit, … Read the rest

Feb 192012
 
An Integrated X-ray and Molecular Dynamics Study of Uranyl-salen Structures and Properties (G. M. Lombardo,  A. L. Thompson,  F. P. Ballistreri,  A. Pappalardo,  G. T. Sfrazzetto,  G. A. Tomaselli,  R. M. Toscano and F. Punzo)

Dalton Trans. (2012), 41, 1951-1960.    [ doi:10.1039/C1DT11758K ]

Uranium complexes of bis(p-tert-butyl-salicylidene)-1,2-diphenylethylenediamine (1) and bis(salicylidene)-1,2-diphenylethylenediamine (2) have been synthesized and investigated by X-ray single crystal diffraction and MD calculations in Periodic Boundary Conditions. Both compounds form crystals which are densely packed and do not provide voids accessible to … Read the rest

Feb 032012
 
Methyl 6-amino-6-oxohexanoate & 3-Methoxy-3-oxopropanaminium chloride (T. Gruber, C. J. Schofield and A. L. Thompson)

Acta Cryst. (2012), E68, o593-o594.    [ doi:10.1107/S1600536812003303 ]

The title compound, C7H13NO3, adopts an approximately planar conformation. The torsion angles in the aliphatic chain between the carbonyl group C atoms range from 172.97 (14) to 179.38 (14)° and the r.m.s. deviation of all non-H atoms is 0.059 Å. … Read the rest