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
The University of Bradford theses are licenced under a Creative Commons Licence.
InstitutionUniversity of Bradford
DepartmentSchool of Life Sciences
MetadataShow full item record
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.
Showing items related by title, author, creator and subject.
Multi-component crystals of 4-phenylpyridine: challenging the boundaries between co-crystal and organic salt formation with insight into solid-state proton transferSeaton, Colin C.; Munshi, Tasnim; Williams, Sara E.; Scowen, Ian J. (2013)Six new multi-component crystals between 4-phenylpyridine and substituted benzoic acids (3-nitrobenzoic acid, 3,5-dinitrobenzoic acid, gallic acid, 4-aminobenozic acid, salicylic acid and 2-aminobenzoic acid) were created and characterized crystallographically to investigate the influence of chemical and structural factors on the hydrogen location between the two components. While the expected intermolecular interactions are formed between the acid and pyridine group in most cases, the gallic acid structure is anomalous forming an unexpected salt with pyridine to hydroxyl interactions. Calculations of the hydrogen bonding motifs indicate that the level of proton transfer (e.g. salt versus co-crystal formation) is not solely a function of the dimer geometry but influenced by the local crystallographic environment. Analysis of the crystal structures indicates the strength of the hydrogen bonding into this motif alters the expected protonation state from chemical considerations.
Scope and limitations of the irreversible thermodynamics and the solution diffusion models for the separation of binary and multi-component systems in reverse osmosis processAl-Obaidi, Mudhar A.A.R.; Kara-Zaitri, Chakib; Mujtaba, Iqbal M. (2017-05)Reverse osmosis process is used in many industrial applications ranging from solute-solvent to solvent-solvent and gaseous separation. A number of theoretical models have been developed to describe the separation and fluxes of solvent and solute in such processes. This paper looks into the scope and limitations of two main models (the irreversible thermodynamics and the solution diffusion models) used in the past by several researchers for solute-solvent feed separation. Despite the investigation of other complex models, the simple concepts of these models accelerate the feasibility of the implementation of reverse osmosis for different types of systems and variety of industries. Briefly, an extensive review of these mathematical models is conducted by collecting more than 70 examples from literature in this study. In addition, this review has covered the improvement of such models to make them compatible with multi-component systems with consideration of concentration polarization and solvent-solute-membrane interaction.
The implications of organizational context for Information Systems and Technology strategy formulation. A study of socio-political factors in global corporations.Smallman, Clive; Hussain, Zahid I.; Vaidya, Anil Vishnu (University of BradfordSchool of Management, 2011-11-09)Information systems and technology strategy has been discussed by many researchers and authors over last three decades. The concepts of business alignment, competitive advantage, value generation etc. have been elaborated and still similar discussions continue. While the advances in IS/IT strategy formulation were being made, the businesses were changing their operating models. More specifically they became global businesses active in multiple geographies at the same time. This research aims to provide deeper understanding of IT developments in global organizations as manifested in the changing social and political environment of the organization and the reciprocal effect of social and political changes on IT strategies. Further it aims to investigate whether the relevant theories and concepts can be integrated to develop a new model that can incorporate the socio-political aspects into IS/IT strategy formulation. To achieve this objective the literature survey was conducted to explore available published papers in the sphere of IS/IT strategy formulation. Considering that the applicability of information systems and technology falls into the sphere of social sciences, the research design focused on the qualitative approach. The primary method of data collection was through semi-structured interviews with IT managers. This was complemented by interviews with business managers and consultants. Further the experiences of the researcher in the earlier role of practitioner were taken into account. Using grounded theory approach the information collected through interviews, own experiences and the data gathered from literature survey were used to develop a new model of IT strategy formulation. The model addresses the context part of IT strategy formulation process. This model development is aimed to counter and account for the political and social aspects of strategy development and deployment in global corporations characterised by diversity of cultures, attitudes and behaviours.