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Acta Cryst. (2014). A70, C675
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For several years we have been making detailed comparisons of the crystal structures of large sets of related compounds in an attempt to understand the factors determining the adoption of particular molecular arrangements within crystal structures. In all these projects, the XPac program [1] was used to identify similarity between structures in 0-dimensions (0D) (discrete molecular arrangements e.g. dimers, trimers etc),1D (chains or stacks), 2D (sheets or planes) and 3D (frameworks or full isostructurality) as a preliminary to the detailed comparison of the similarities so identified. As part of a larger crystallographic project to investigate the relationship between structure and chirality, we have synthesized and determined crystal structures of families of monosubstituted racemic mandelic acids with fluoro, chloro, bromo, iodo, trifluoromethyl, methyl and methoxy substituents at the ortho, meta and para positions. The substituted mandelic acids are polymorphically prolific and with the inclusion of unsubstituted mandelic acid, 28 structures have been compared. Of special interest has been 3-chloromandelic acid (3-ClMA), for which so far five polymorphs have been discovered: three racemic, two of which are isostructural [2], and two enantiopure. A crystal structure prediction (CSP) study of 3-ClMA has been carried out using the CrystalPredictor [3] and CrystalOptimizer [3] algorithms to generate the crystal energy landscape which is exceptionally dense with 3050 structures within 20 kJ mol-1. Many of these are more stable than the known forms, which is consistent with the complex crystallisation behaviour observed. From our observations of the crystallisation behaviour of substituted chloromandelic acids in general and the CSP study of 3-ClMA, we expect to discover further polymorphs of 3-ClMA and to this end cross-seeding experiments using crystals from differently substituted mandelic acids and a comprehensive polymorph screen are at present being undertaken.

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Acta Cryst. (2014). A70, C1690
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Supplementary Information supporting publications is not uniform across journals, is generally not 100% representative of the work undertaken, is not structured or comprehensive and therefore is often not fully considered in review. In chemistry articles where characterisation techniques are applied widely, crystallography is the exception in that there are universally agreed processes and protocols for presenting the scientific findings and the supporting data. Crystallography can therefore lead the way! Our approach to solving the broader problem of availability of supporting information is to expose the observations of the researchers who conducted the work when it was performed. By combining these observations with related data (eg in information management systems) and linking these with the article there is the potential for a much richer system for data supporting a publication. The Electronic Laboratory Notebook (ELN) plays a key role by establishing authenticity, adding structure to the record and having the capacity to be made open. We present a formal publication in Chemistry Central Journal (http://journal.chemistrycentral.com/content/7/1/182) which is a collaborative piece of work between the UK National Crystallography Service (University of Southampton) and the University of Greenwich, where the data supporting the article is not contained within it, but is openly exposed at source by an ELN and a crystal structure repository. We draw on the experience of crystallographic publishing and aligning that with the other characterisation techniques alongside which crystal structures are routinely published and related. The article presents all the supplementary information (some 35 or so data sources) in a single graphical approach, which permits examination of synthesis, spectra & structures in-line and provides a link to the original ELN record. All records are assigned a Digital Object Identifier (DOI) by a system established within the University.
Keywords: data publication.

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Acta Cryst. (2014). A70, C1699
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Although crystals suffering radiation damage is a well-known and studied phenomena for macromolecular crystallography[1], as far as we are aware there appears to be no such published work relating to chemical crystallography. However, there are numerous anecdotal accounts of disintegrating crystals and resolution progressively dropping off that have been ascribed to radiation damage. Since the start of operations on the small molecule synchrotron beamline I19[2] at Diamond Light Source, there have been multiple comments from several users observing sample damage in the beam. The UK National Crystallography Service[3] handles a wide variety of samples and a number of these have experienced radiation damage. In order to understand the causes and symptoms of this effect in greater detail some controlled experiments were performed. A series of experiments were conducted on crystals that were known to undergo radiation damage in order to determine some quantification of the effect. Additionally the aim is to understand what one might be able to do to mitigate against the damage caused and determine whether the effects observed are similar to those of macromolecular crystallography. The effects of varying the collection temperature, overall dose, dose rate and wavelength of X-ray used were all tested and normalised for each sample. Samples where radiation damage has been observed were chosen and were also required to be air stable and preferably not suffer from solvent loss, in order to minimize problems of non-reproducibility. Those chosen to probe this effect were: 1. A gold complex - has potential to suffer heavily from absorption effects. 2. A nickel complex with significant solvent water - this could to some extent mimic the behaviour exhibited by proteins. 3. A small organic compound - an example of unexpected decay. The poster will summarise the results of these experiments and contrast them with data collected on a high intensity rotating anode laboratory source.
Keywords: Radiation; Damage.
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