Simon J. Coles

Transition-metal complexes with oxidoborates. Synthesis and XRD characterization of [(H3NCH2CH2NH2)Zn{κ3O,O′,O′′-B12O18(OH)6-κ1O′′′}Zn(en)(NH2CH2CH2NH3)]·8H2O (en=1,2-diaminoethane): a neutral bimetallic zwiterionic polyborate system containing the ‘isolated’ dodecaborate(6−) anion

Abstract The title compound, [(H3NCH2CH2NH2)Zn{κ3O,O′,O′′-B12O18(OH)6-κ1O′′′}Zn(en)(NH2CH2CH2NH3)]·8H2O (en=1,2-diaminoethane) (1), was prepared as a crystalline solid in moderate yield from the reaction of B(OH)3 with [Zn(en)3][OH]2 in aqueous solution (15:1) ratio. The structure contains a neutral bimetallic complex comprised of a unusual dodecaborate(6−) anion ligating two [H3NCH2CH2NH2Zn(en)n]3+ centers in a monodentate (n=1) or tridentate (n=0) manner.

Research Data Management: administration, raw diffraction data, structure factors and coordinates at the UK's National Crystallographic Service (NCS)

The NCS has led the way for chemical crystallography for around 15 years in developing approaches to addressing this problem1. The eCrystals project (http://ecrystals.chem.soton.ac.uk/) developed an institutional repository approach to curating and disseminating coordinates, structure factors and a range of other information relating to the ‘derived’ data from a crystallographic experiment. However, raw diffraction data, although being rigorously archived and in the last 15 years highly curated, is only available on request directly to the NCS. eCrystals has been designed to act as a discipline specific data repository, which has resulted in a pragmatic metadata scheme for the description of its contents and this promotes discovery and reuse of the material it makes available.

Crystallography as an introduction to cheminformatics

Information management and its subsequent analysis to derive new knowledge is ubiquitous in the digital age, with companies such as Google and Amazon being built on such foundations and becoming hugely successful as a result. As a research discipline chemistry is rather behind in this area – there is not a significant culture of the whole discipline working coherently to generate large bodies data that can be used to perform further scientific research. In part this can be attributed to a lack of understanding and education as to how and why Cheminformatics might be used. Moreover, Cheminformatics is used at a significant level in chemical industries and employers are anxious to recruit graduates with a good understanding of the principles – irrespective of whether it is put into practice or not, as it is important for everyone in the organisation to understand why collecting and using data is important.

Using charge density to understand structure–property relationships in pharmaceutical co-crystals

Co-crystals have emerged over recent years as a promising way to modify the properties of a compound through judicious selection of a co-former molecule. Hence they provide attractive new and alternative solid forms particularly in pharmaceutical applications, using active pharmaceutical ingredients (APIs). Traditional design strategies utilise supramolecular synthons facilitated by strong hydrogen bonding interactions, chosen depending upon the functional groups present in the molecule of interest. If no, minimal, or only restricted (through sterics) functional groups are present on a molecule the design is more challenging. Studies on such molecules are limited and primarily use trial and error-based methods for co-former selection hence, an alternative method is required. Two contrasting APIs have been studied. One, lonidamine, contains a typical hydrogen bonding functional group (carboxylic acid) for which a supramolecular synthon approach is appropriate, whilst the second, propyphenazone, contains only a single, sterically hindered, hydrogen bond acceptor group (carbonyl) and no donor groups. Co-former selection for propyphenazone required an alternative prediction methodology and a knowledge-based design strategy was designed and implemented.1 Both systems resulted in a number of new multicomponent materials including co-crystals, salts and solvated forms. All were characterised using X-ray diffraction techniques with physicochemical properties measured, thus allowing comparisons between the different materials to be realised and structure-property relationships to be analysed. Charge density studies allow analysis at the electronic level, particularly regarding the nature of the interactions occurring between the different molecules through property calculations at bond critical points (BCPs). A systematic approach has been taken with the two systems, applying small changes to the co-former structure and investigating its effect via the resulting electronic distribution. Using a series of related structures, trends can be identified and thus rules for co-former selection / physicochemical property modification learnt.

CCDC 1033101: Experimental Crystal Structure Determination

Related Article: Gavin W. Roffe, Sarote Boonseng, Christine B. Baltus, Simon J. Coles, Iain J. Day, Rhiannon N. Jones, Neil J. Press, Mario Ruiz, Graham J. Tizzard, Hazel Cox, John Spencer|2016|RSOS|3|150656|doi:10.1098/rsos.150656

CCDC 1033102: Experimental Crystal Structure Determination

Related Article: Gavin W. Roffe, Sarote Boonseng, Christine B. Baltus, Simon J. Coles, Iain J. Day, Rhiannon N. Jones, Neil J. Press, Mario Ruiz, Graham J. Tizzard, Hazel Cox, John Spencer|2016|RSOS|3|150656|doi:10.1098/rsos.150656

CCDC 1033103: Experimental Crystal Structure Determination

Related Article: Gavin W. Roffe, Sarote Boonseng, Christine B. Baltus, Simon J. Coles, Iain J. Day, Rhiannon N. Jones, Neil J. Press, Mario Ruiz, Graham J. Tizzard, Hazel Cox, John Spencer|2016|RSOS|3|150656|doi:10.1098/rsos.150656

An extensive study of bromination of cis,trans,trans-1,5,9-cyclododecatriene: product structures and conformations [Addition and correction]

Bromine has been added to cis,trans,trans-1,5,9-cyclododecatriene under various reaction conditions. All expected direct addition products have been isolated, and their structures have been determined by microanalysis, NMR and X-ray crystallography. Advanced NMR techniques were used to determine solution conformations of several of the compounds, enabling comparison with the solid-state conformations obtained by crystallography.