Directing the Assembly of Multicomponent Organic Crystals. Synthesis, characterisation and structural analysis of multicomponent organic systems formed from dynamic processes.
AuthorAlomar, Taghrid S.
SupervisorScowen, Ian J.
KeywordMulticomponent systems, Organic, PXRD, Crystal engineering, X-ray crystallography, Vibrational spectroscopy, Dynamic covalent chemistry, Multicomponent systems, organic, PXRD, crystal engineering, x-ray crystallography, vibrational spectroscopy, dynamic covalent chemistry.Multicomponent systems, organic, PXRD, crystal engineering, x-ray crystallography, vibrational spectroscopy, dynamic covalent chemistry, Multicomponent organic systems, Cogent assembly
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InstitutionUniversity of Bradford
DepartmentSchool of Life Sciences
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AbstractDirected assembly of molecular solids continues to attract widespread interest with its fundamental application in a wide range of commercial settings where control of the crystalline state of materials corresponds with product performance. These arenas include pharmaceuticals, personal care formulations, foods, paints and pigments and explosives. In recent times, the assembly of multicomponent organic systems has achieved considerable impetus with the widespread interest in co-crystal systems. However, cogent assembly (or engineering) of multicomponent materials is still in its infancy. Considerable advances in crystal design have been made through consideration of intermolecular ‘synthons’ – identifiable motifs utilising hydrogen bonds – but the translation of other molecular information (conformation, chirality, etc.) into solid state properties (e.g. long-range (translational) symmetry, crystal chirality) remains poorly understood. In this study, we have attempted to evaluate the influence of a chiral centre adjacent to molecular synthons to identify potential translation of information into the solid form. We have compared the co-crystallisation of nicotinamide with both the racemic mixture of malic acid against that with an enantiomerically pure form of the acid (L-malic acid). As well as DL-phenyllactic acid and L-phenyllactic acid. iii It is apparent that recognition between enantiomeric molecular forms play a significant role in the assembly of these systems. This mechanism can be considered independently from the H-bonding networks supporting the hetero-molecular interactions (e.g. acid-amide recognition). Discrimination and control of such interactions may play a role in transmitting chiral molecular information into solid state multi-component assemblies. In order to develop an understanding of co-crystal formation in chiral and achiral forms with intermolecular interactions, the CSD and crystal structures were obtained to do the analysis of how co-crystals pack. This study has also investigated the use of boronic acids. The aim of this study was to investigate the modification of the hydrogen bonding environment within the hydrogen bonded multi-component systems of boroxines. The study also attempted to determine how the starting materials drive the systems between the boronic acid co-crystal and the boroxine adduct.
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