Chirality (2008), 20(7), 863-870. Â Â [ doi:10.1002/chir.20561 ]
3 alpha,12 alpha-Dihydroxy-5 beta-cholan-24-oic acid (deoxycholic acid DCA) is able to discriminate between the R- and S-enantiomers of camphorquinone and endo-(+)-3-bromocamphor and select only the S-enantiomers from a racemic mixture. DCA forms novel well ordered 1:l adducts with (1S)-(+)-camphorquinone and (1S)-endo-(-)-3-bromocamphor, both of which have been characterized … Read the rest
J. Appl. Cryst. (2008), 41, 491-522. Â Â [ doi:10.1107/S0021889808007279 ]
Most modern small-molecule refinement programs are based on similar algorithms. Details of these methods are scattered through the literature, sometimes in books that are no longer in print and usually in mathematical detail that makes them unattractive to nonprogrammers. This paper aims to discuss these … Read the rest
J. Appl. Cryst. (2008), 41, 531-536. Â Â [ doi:10.1107/S0021889808005463 ]
Librational motion within a crystal structure distorts the measured bond distances and angles from their physical values. TLS analysis of a rigid molecule or a rigid part of a molecule allows the calculation of bond-length and angle corrections. Until now, no estimate of the error … Read the rest
The Annual Meeting of the British Crystallography Association was held in York. Contributions from Chem. Cryst. included:
Anna Collins, Richard I. Cooper, Andrew R. Cowley, David J. Watkin
2-(1-Hydroxy-2-methyl-propyl)-2,5-dihydro-furan-2-carboxylic acid diisopropylamide: A study of a phase transition to a pseudosymmetrical Z′=2 structure (Poster)
James Haestier, Mustapha. Sadki, Amber L. Thompson and David J. Watkin
Cell … Read the rest
Acta. Cryst. (2007), 63, 303-308. [ doi:10.1107/S0108768106055212 ]
A new polymorph of 2,4-dihydroxybenzoic acid is reported. The structure was characterized by multiple-temperature X-ray diffraction and solid-state DFT computations. The material shows a geometric pattern of hydrogen bonding consistent with cooperativity between the intermolecular carboxylic acid dimer and intramolecular hydrogen bonds. The presence of proton … Read the rest
J. Appl. Cryst. (2006), 39, 842-849. Â Â [ doi:10.1107/S0021889806038489 ]
A sizeable proportion of structures with Z‘ = 2 are thought to exhibit pseudosymmetry, but establishing the extent of the deviation from true symmetry is problematic. By considering both the conformational similarity between the independent molecules and the way in which they are related … Read the rest
J. Chem. Inf. Comput. Sci. (2004), 44, 2133-2144. [ doi:10.1021/ci049780b ]
The crystallographically determined bond length, valence angle, and torsion angle information in the Cambridge Structural Database (CSD) has been made accessible by development of a new program (Mogul) for automated retrieval of molecular geometry data from the CSD. The program uses a system … Read the rest
Acta. Cryst. (2004), A60, 322-325. [ doi:10.1107/S010876730401219X ]
β-U4O9 is a superlattice structure based on the fluorite arrangement of UO2. The U atoms occupy positions close to those in UO2 and the additional O atoms are accommodated in cuboctahedral clusters of -43m symmetry, which are centred on the special … Read the rest
J. Appl. Cryst. (2004), 37, 545-550. Â Â [ doi:10.1107/S0021889804009847 ]
The program CRYSTALS [Betteridge, Carruthers, Cooper, Prout & Watkin (2003). J. Appl. Cryst. 36, 1487] has been extended to include an option for the refinement of a continuous electron density distribution lying along a line, a ring or on the surface of a sphere. … Read the rest
J. Appl. Cryst. (2003), 36, 1487. Â Â [ doi:10.1107/S0021889803021800 ]
CRYSTALS version 12 contains a modern crystallographic user interface, and novel strategies that incorporate chemical knowledge and crystallographic guidance into the crystal structure analysis software.
Electronic reprints
Publisher’s copy
… Read the rest