Hydration, polymorphism and disorder in organic solids, including materials of pharmaceutical relevance.

Austin, Talbir Kaur 2006. Hydration, polymorphism and disorder in organic solids, including materials of pharmaceutical relevance. PhD Thesis, Cardiff University.

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Abstract

The studies described in this thesis are concerned with understanding and rationalising the inter-relationships between structural and other physical properties of organic solids encompassing hydrates, polymorphs and homologous series. This is achieved through assessment of the crystal packing arrangements and the nature of the intermolecular interactions, which may have a profound impact on the stability and physical properties of organic materials. Such an understanding is critically important when selecting or designing materials that demonstrate specific defined properties. The first part of the thesis describes the relationships between hydrate and anhydrate phases, exemplified by tetraphenyl phosphonium bromide as a model system. The relative inter-relationships between the two main phases of this material are rationalised by characterisation of both structural and dynamic properties. The second aspect is focused on the influence of short-range interactions on the long-range periodicity and subsequent properties of materials using 4-hydroxy benzoic acid esters as a homologous series to explore odd-even alternations, seen for other series containing long chain functionalities. In this study, the nature of short-range interactions is found to correlate with the observed odd-even alternation in material properties, with deviations from these observations shown to correspond to the presence of significant disorder in the structures. The third aspect concerns the properties of a polymorphic pharmaceutical material, AZD7140. The crystal structures for both polymorphs were solved and assessment of hydrogen bonding motifs and thermodynamic evaluation using phase diagrams allowed the selection of a robust polymorph as a suitable development material. The final aspect of the thesis concerns strategies that may be employed to solve structures of disordered systems directly from XRPD data using direct space methodology.

Item Type:	Thesis (PhD)
Status:	Unpublished
Schools:	Chemistry
Subjects:	Q Science > QD Chemistry
ISBN:	9781303205156
Funders:	AstraZeneca
Date of First Compliant Deposit:	30 March 2016
Last Modified:	17 Nov 2014 15:50
URI:	https://orca.cardiff.ac.uk/id/eprint/56079

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