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LAI, ROMINA. "Crystal engineering of MOF based on polypyridyl ligands and coordinatively unsatured NiII ions." Doctoral thesis, Università degli Studi di Cagliari, 2016. http://hdl.handle.net/11584/266765.
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The thesis reports on the synthesis, structural and spectroscopic characterization of coordination polymers obtained by reacting dithiophosphato [((RO)2PS2)2Ni] and dithiophosphonato [Ni(ROpdt)2] NiII complexes [ROpdt = (RO)(4-MeOC6H4)PS2; R = Me, Et] with a variety of polypyridyl donors prepared and characterized as a part of the PhD work, selected according to their rigidity, topology, number and position of donor atoms.
Chapter 1 An introductory part is presented which reports the main concepts of supramolecular chemistry and crystal engineering. The objectives of the research are outlined and the square planar NiII phosphorodithioato complexes used as the building blocks in the building up of the polymers introduced. The tendency of these coordinatively unsaturated complexes to axially bound two additional donor molecules by reaching octahedral coordination geometry in a quite predicable way, is discussed. Chapter 2 A discussion of the results is presented mainly focused on structural description motifs and crystallographic datasets obtained through the deliberate construction of coordination polymers obtained by reacting NiII phosphorodithioato complexes with various bi-pyridyl donors. Three different typologies of ligands were prepared: bidentate rigid spacers such as the 1,4-bis(3-pyridyl)-butadiyne ligand; semi-rigid bidentate spacers such as the 2,5-bis(4-pyridyl)-4-thia-1,3-thiazolidine and 2,5-bis-(3-pyridyl)-4-thia-1,3-thiazolidine ligands, and a set of tridentate spacers such as 1 1,3,5-benzenetricarboxylic acid-1,3-bis-4-pyridyl ester. The ligands were synthesized following different synthetic routes here described. The self-assembly process is based on the capability of the coordinatively unsaturated NiII ion of the square-planar phosphorodithioato complexes to bind suitable bipyridyl and tripyridil-based spacers thus forming 1D and 2D coordination polymers with different geometrical and topological features. It has been demonstrated that the primary structural motif of the polymers depends mainly on the features of the pyridyl-based spacers such as length, rigidity, number and orientation of the donor atoms, whereas the substituents on the phosphorus atoms play a crucial role in determining the final network through secondary intermolecular interactions involving the polymeric chains.
Chapter 3 The experimental procedures and spectroscopic characterizations are here reported along with all the materials, instruments, synthetic procedures, crystallization methods, and technical parameters used for the spectroscopic investigations.
Chapter 4 The conclusions about this research work and new perspectives in coordination polymers building-up are here reported.
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Perry, John Jackson. "Hierarchical complexity in metal-organic materials : from layers to polyhedra to supermolecular building blocks." [Tampa, Fla] : University of South Florida, 2009. http://purl.fcla.edu/usf/dc/et/SFE0003227.
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Lloyd, Gareth Owen. "Crystal engineering of porosity." Thesis, Link to the online version, 2006. http://hdl.handle.net/10019/1087.
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Venkatasubramanian, Ulaganthan. "Crystal engineering with heteroboranes." Thesis, Heriot-Watt University, 2004. http://hdl.handle.net/10399/252.
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Khanal, Pitambar. "Crystal Engineering with Piperazinediones." Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/612051.
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Non covalent interactions are valuable tools for crystal engineering. Hydrogen bonding often plays a central role for molecular association among possible non covalent interactions. Together with hydrogen bonding, arene-arene interactions and van der Waals interactions can control crystal assembly. Understanding non covalent interactions permits the design of molecules whose functionalities can interact non covalently so that molecules will pack in a predicted fashion. For two decades Prof. Mash's group has been studying crystal packing based on a piperazinedione core scaffold which can have three orthogonal non covalent interactions and lead to controlled three dimensional crystal packing. Alkoxy-substituted piperazinediones were previously studied for crystal packing and liquid crystal properties. It was found that alkoxy piperazinediones pack in three dimesions as designed and exhibit interesting thermochemical properties. Given that small changes in structure can cause large changes in packing and liquid crystal properties, the replacement of alkoxy groups with alkyl groups in molecules provides an opportunity to investigate the role of oxygen in crystal packing and liquid crystal properties. A series of alkyl piperazinediones was synthesized in a convergent way where an intermediate tetrabromide was converted into a series of tetra alkyne piperazinediones, then into tetra alkyl piperazinediones. This approach overcame limitations in the synthesis of alkoxy piperazinediones, where every target molecule requires 10 to 11 steps starting from 2,3-dimethylbenzene-1,4-diol (Scheme 2.1). Crystal structure analyses were done for three different piperazinediones. It appears that crystal packing of alkyl piperazinediones mimics that of alkoxy piperazinediones.
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Kavuru, Padmini. "Crystal engineering of flavonoids." [Tampa, Fla] : University of South Florida, 2008. http://purl.fcla.edu/usf/dc/et/SFE0002463.
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Batchelor, E. "Acid:base Co-crystal formation in crystal engineering and supramolecular design." Thesis, University of Cambridge, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.596460.
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The chemical and physical properties of organic molecular crystals depend on both the molecular and crystal structure. The systematic approach to understanding and controlling crystal structure lies in the field of "crystal engineering". One strategy to emerge within crystal engineering has been the utilisation of specific interactions or couplings / synthons to predictably build supramolecular arrays such as tapes, ribbons or sheets. These arrays form a subset of the crystal structure. While many couplings take the form of cyclic motifs in which component interactions are of comparable strength, a cyclic coupling consisting of an O-- H...N and a C-H...O interaction was noted as having a potential use in designing supramolecular arrays. This type of strong / weak coupling is possible upon the interaction of an N-heterocycle with a carboxyl group. The following research describes the co-crystallisation of various N-heterocyclic bases with a number of olefinic and aliphatic dicarboxylic acids. The crystal structures of various complexes of phenazine, 1,10-phenanthroline and quinoxaline were solved from single-crystal X-ray diffraction data and are discussed. Two distinct strong / weak couplings were identified within the three sets of co-crystals. A comparison of the relative stabilities of the two couplings was made using the quinoxaline system. Supramolecular tapes were observed in all of the phenazine co-crystals and in three of the four quinoxaline co-crystals. (The stoichiometry of the phenazine co-crystals may be related to the position of the carboxyl groups on the participating acid.) The packing of the tapes is discussed with particular reference to tape topography and inter-tape C-H...O interactions. Proton transfer occurred in four of the five co-crystals of 1,10-phenanthroline. Co-crystals were prepared via two methods: by growth from a solution and by grinding of a physical mixture of the starting components. Solid-state grinding was found to be a viable method for the preparation of co-crystals. Complexes of 1,10-phenanthroline prepared via the two routes were analysed using solid-state 13C MAS NMR and the effects of protonation on certain carbon resonances is discussed.
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Griffiths, J. "Crystal engineering for nonlinear optics." Thesis, University of Cambridge, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.599722.
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Chapter Two details the design, synthesis and characterisation of some compounds of general formula p-DC6F4A-p’. Donor and acceptor groups are discussed both in the context of maximising the molecular NLO response, and in the context of the promotion of polar chain formation through supramolecular synthons. Of the ten compounds presented in this chapter, nine are noncentrosymmetric. Preliminary NLO measurements show that these nine compounds exhibit an appreciable SHG response. Semi-empirical calculations were performed on these and related systems to determine molecular hyperpolarisabilities. Similar calculations were also used to draw Molecular Electrostatic potential maps for these compounds in an attempt to rationalise the observed packing. Chapter Three discusses some compounds of general formula DC6F4C6F4A. The synthetic difficulties associated with the preparation of these perfluorinated biphenyl derivatives are highlighted, and semi-empirical calculations are used to identify some idealised systems. The syntheses and crystal structures of some methoxy substituted derivatives are reported. Chapters Four and Five discuss some compounds in which donor-acceptor substituted rings are linked by delocalised spacer groups. The synthesis and characterisation of some donor-acceptor substituted aromatic Schiff base compounds is presented in Chapter Four, along with some initial calculations and NLO measurements. Chapter Five describes the design, synthesis and characterisation of some thiazyl chain compounds. UV measurements and preliminary calculations on some of these systems are also presented.
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Mukherjee, Sreya. "Crystal Engineering of Pharmaceutical Cocrystals." Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3258.
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Pharmaceutical cocrystals use principles of crystal engineering for the design of crystalline forms of drugs and can improve their solubility, bioavailability, stability and other important properties without changing the efficacy of the drug. Herein reported are pharmaceutical cocrystals of two API's, caffeine and Pentoxifylline.
Research has indicated that caffeine has the ability to reverse AB; plaque deposition in the brain (believed to be the primary cause of Alzheimer's pathogenesis) and thus revert memory and improve cognitive impairment. But owing to the fast absorption rate and short half life, a controlled release formulation of caffeine would be clinically beneficial. Thus, novel cocrystals of caffeine are presented with varying solubilities with respect to caffeine. The pharmaceutical cocrystals of caffeine used herein include: caffeine.cyanuric acid monohydrate, caffeine.syringic acid tetrahydrate, caffeine.chlorogenic acid and caffeine.catechin hydrate. Three caffeine cocrystals were prepared in our lab previously which include caffeine.ferulic acid, caffeine.ethyl gallate dihydrate and caffeine.caffeic acid. In addition, six caffeine cocrystal forms were reproduced from the literature and included in the solubility study: caffeine.quercetin, caffeine.salicylic acid, caffeine.1-hydroxy-2-napthoic acid, caffeine.gallic acid hemihydrate, caffeine.ellagic acid monohydrate and caffeine.coumaric acid. Dissolution studies were performed in aqueous media at room temperature. All of the cocrystals decreased the solubility of caffeine with the highest being a 278 fold decrease in the solubility of caffeine. Analysis of melting point, crystal packing efficiency and solubility of cocrystal former with solubility was also done to determine if they influenced the solubility. Presented herein are the results of the analyses. It was seen that solubility of the cocrystal former had no effect on the decrease in cocrystal solubility. Moreover melting point and solubility of the cocrystal could not be correlated probably due to the variability in the cocrystal formers. Crystal packing efficiency though did not show a high correlation with solubility but it was seen that highest solubility achieved by pure caffeine achieved the lowest crystal packing efficiency and vice versa suggesting its role in cocrystal solubility.
Pentoxifylline is contraindicated for its use in autism. But owing to high solubility of the drug, a less soluble form of the drug would help in decreasing the half life and thereby help in forming a sustained form of the drug by modifying the inherent solubility of the API. Here, novel cocrystals of Pentoxifylline are presented with varying solubilities with respect to the API. The pharmaceutical cocrystals used herein include: pentoxifylline.benzoic acid, pentoxifylline.1-hydroxy-2-napthoic acid, pentoxifylline.salicylic acid, pentoxifylline.gallic acid, pentoxifylline. salicylamide, pentoxifylline.coumaric acid, pentoxifylline.caffeic acid and pentoxifylline.catechin hydrate. Dissolution studies were also performed in aqueous media at room temperature. All of the cocrystals decreased the solubility of Pentoxifylline with the highest being a 99 fold decrease in the solubility with pentoxifylline.coumaric acid. On analyzing melting point, crystal packing efficiency and relation of solubility of cocrystal former with solubility of cocrystal, as was done in the case of caffeine, the parameters showed no effect on solubility of the cocrystal.
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Hoxha, Kreshnik. "DNA bases in crystal engineering." Thesis, University of Hull, 2014. http://hydra.hull.ac.uk/resources/hull:11660.
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The work described in this thesis focuses on understanding the solid state interactions of organic molecules such as DNA nucleobases using established principles from crystal engineering and the synthon theory. Studying the intermolecular interactions is an indispensable tool to the crystal engineer when it comes to identifying functional groups which generate synthons that govern molecular recognition and self-assembly. Chapter 3 focuses on the growth and design of single crystal materials of DNA bases and their carboxylic acid derivatives with various other molecules. The aim of the chapter was to probe the hydrogen bonding displayed by these systems. The challenges associated with dissolving the nucleobases in organic and aqueous solvents prompted alternative synthetic route to mitigate solubility challenges. Altering the pH of the system was found useful in aiding dissolution. Such synthetic approach has led to the preparation of novel nucleobase salts of bis-guaninium sulphate in three different hydrate forms. The material obtained was a channel hydrate and it was possible to remove water partially and fully while retaining crystallinity. No structural collapse was observed upon full dehydration and the material obtained contained an empty channel hydrate. Co-crystallisation of cytosine with 1,10-phenanthroline is discussed in depth and the results are compared to crystal structure prediction results to rationalise co-crystal formation from an energetic perspective. Calculations on the energy landscape revealed that in the case of cytosine and 1,10-phenanthroline there is a favourable energetic driving force for co-crystallisation. This, however, does not apply to the co-crystallisation of the other DNA bases with 1,10-phenanthroline as these systems did not produce co-crystals and remained as mixtures of precursors. The chapter also describes structural features of thymine acetic acid, melaminium nitrilotriacetate trihydrate and co-crystals of caffeine with 2-nitroterepthalic acid. These structures are closely examined for their hydrogen bonding motifs. Chapter 4 covers a wide range of coordination compounds which relate to hydrogen-bonded networks of DNA nucleobases and their carboxylic acid derivatives. These complex architectures contain both coordination bonds as well as intermolecular interactions in the form of hydrogen bonding and stacking interactions. Metal-dipicolinate complexes treated with adenine and cytosine afforded hydrogen-bonded networks where protonated DNA bases interacted with the ligand via hydrogen bonding. The chapter discusses the role of water molecules in acting as spacers and stabilising crystal structure, especially in cases where there is an imbalance of hydrogen bond donors and acceptors. Orotic acid was heavily used owing to its chelating nature. This part of Chapter 4 focuses on novel crystal structures where orotic acid utilises its hydrogen bonding capability. An extensive discussion is provided on how the level of hydration impacts crystal packing and alters synthon formation. In addition, the chapter also focuses on the structural changes resulting from changing the position of the functional group in the ligands.
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Aboarayes, Dalia A. "Crystal Engineering of Nutraceutical Cocrystals." Scholar Commons, 2009. https://scholarcommons.usf.edu/etd/1820.
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The work presented herein focus upon crystal engineering of nutraceutical cocrystals. Cocrystals are considered unique solid dosage form which has many advantages over other traditionally known solid forms. Furthermore, cocrystals have proven to improve stability, solubility and bioavailability of Active Pharmaceutical Ingredient (API) as shown in the case of carbamazepine and other APIs in previous studies.
Crystal engineering is commonly used to design new solid forms based on the bases of supramolecular chemistry. In this study, crystal engineering based on intensive Cambridge Structural Database (CSD) analysis used to predict and design new cocrystals of targeted nutraceuticals. Two nutraceuticals were selected for this study; resveratrol and citric acid. The rationale behind selecting resveratrol was to improve its solubility and, accordingly, bioavailability. On the other hand, citric acid is known as a highly soluble and safe nutraceutical, and thus it can be used as a coformer. Five new cocrystals were prepared and characterized using a variety of techniques that include single crystal X-ray diffraction (XRD), powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), FT-IR, and thermo-gravimetric analysis (TGA). Most of the reported cocrystals were obtained using different techniques; solvent slow evaporation, mechanichemical approach, slurry, and from melt. Moreover, dissolution test has been performed on resveratrol and two of its cocrystals, using UV-vis spectrophotometer, where the data demonstrate that through cocrystallization with different cocrystal formers, solubility of resveratrol could be greatly modified, and further controlled.
The polymorphism phenomenon is encountered, and accordingly addressed, herein where four novel polymorphs were obtained during cocrystallization attempts. Polymorphism has a significant importance in industry, in general, and in pharmaceutical industry, in particular, due to the vast differences in physical properties of polymorphs. Furthermore, the study of polymorphism provides valuable information essential to understand how different crystal forms are attained.
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Azabi, Y. O. "Spiral photonic crystal fibers." Thesis, City, University of London, 2017. http://openaccess.city.ac.uk/19372/.
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This thesis is concerned with the study of special types of photonic crystal fibers (spiral) and their optical properties. The work is carried out using simulation techniques to obtain the modal field profile and properties for the designs. The method used in solving the Maxwell’s equations is the full vectorial finite element method with the implementation of penalty function and perfectly matched layer. The penalty function is used to eliminate nonphysical solutions. The perfectly matched layer is integrated to absorb rays of light traveling away from the core. These rays are absorbed by the layer and do not reflect back to negatively influence the results. The spiral shapes are implemented in the distribution of the holes in the cladding region of the photonic crystal fiber to determine the photonic crystal fiber properties. Three different spirals have been introduced which are equiangular, Archimedean and Fermat’s spiral. The study of the effective refractive index, effective area and dispersion with varying spiral parameters have been carried out and the results are analyzed to understand the effect of each parameter. The variation of similar parameters in the spirals leads to similar variation in the optical properties under consideration. Furthermore, the equiangular spiral photonic crystal fibers (ES-PCF) have been investigated in two different dimensional scales. The scales are in comparison with the wavelength of operation in the first case when core size is larger than the operating wavelength. In this case the total dispersion of the fiber has slightly higher values than the material dispersion but similar curve and slope. On the other hand, when the core size is comparable with the wavelength of operation, the dispersion is varying significantly with varying the spiral parameters. The effective area can be made very small and therefore the nonlinearity of the fiber very large to facilitate non-linear applications such as super continuum generation. The equiangular spiral photonic crystal fiber has been modified slightly where the position of holes in the third ring are shifted further from the center and their size is much bigger. This manipulation is proposed in an algorithm in this thesis to facilitate the fabrication of ES-PCF using an adaptive stack and draw technique. The design shows similar optical behavior to an ideal spiral and its dispersion has been tailored for supercontinuum generation.
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Youssef, Peter George Asaad. "Experimental and numerical investigation of a new MOF based adsorption water desalination system." Thesis, University of Birmingham, 2018. http://etheses.bham.ac.uk//id/eprint/8376/.
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In this research, performance of adsorption desalination systems is investigated numerically and experimentally through number of techniques including the use of advanced adsorbent materials known as metal organic frameworks (MOFs), various cycle configurations and operating conditions. A Simulink model was developed to simulate the heat and mass transfer processes associated with the adsorption/desorption processes, evaporation of seawater and condensation of potable water. This model has been used to investigate a number of new adsorbents; "AQSOA-Z02", "Aluminum Fumarate", "CP0-27Ni" and "MIL-l 01 Cr" for the purposes of water desalination and cooling as a secondary output. Number of operating parameters have been investigated including; effect of condenser, evaporator and bed's heating secondary fluid temperatures as well as half cycle time. It was concluded that decreasing condenser temperature, enhances cycle performance, therefore, a new system configuration was developed that enables decreasing the condenser temperature by utilizing all or part of the cooling effect produced in the evaporator which resulted in 314% increase in water production than conventional cycle. Two experimental testing facilities were developed to investigate CP0-27Ni and Al-Fumarate which resulted in maximum daily water production (SDWP) of 22.8 and 25.3 m3 .tonne·'.day·' respectively, while the maximum SDWP reported experimentally for Silica-gel is 13.46 m3 .tonne·' .day·'.
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Weyna, David Rudy. "Crystal Engineering of Multiple Component Crystal Forms of Active Pharmaceutical Ingredients." Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3406.
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Enhancing the physicochemical properties of solid-state materials through crystal engineering enables optimization of these materials without covalent modification. Cocrystals have become a reliable means to generate novel crystalline forms with multiple components and they exhibit different physicochemical properties compared to the individual components. This dissertation exemplifies methodologies to generate cocrystals of active pharmaceutical ingredients (API's) based upon knowledge of supramolecular interactions (supramolecular synthons), while focusing on enhanced delivery through in vitro and in vivo processes with both salts and cocrystals respectively.
The utility of mechanochemistry involving small amounts of an appropriate solvent, or solvent drop grinding (SDG), has been shown to reliably reproduce cocrystals with the anti-convulsant carbamazepine that were originally obtained by solution crystallization. This technique has been confirmed as a reliable screening method using solvents in which both components exhibit some solubility. The benefits of this technique lie in the time and cost efficiency associated with it as well as its inherently small environmental impact making it a "Green" method. SDG was also used as an efficient way to discover cocrystals of the anti-inflammatory meloxicam with carboxylic acids after analysis of existing reports and the analysis of structural data from the Cambridge Structural Database (CSD) to guide the choice of coformer. It has been shown that SDG can be used to screen for cocrystalline forms that are also obtainable by solution crystallization which is important in later stage development and manufacturing including but not limited to large scale up processes. Single crystals suitable for single crystal X-ray diffraction were obtained with meloxicam and two of the coformers, fumaric and succinic acid. Some of the meloxicam cocrystals exhibited enhanced pharmacokinetic (PK) profiles in rats exemplifying significantly higher serum concentrations after only fifteen minutes and consistently higher exposure over the time studied while others maintained lower exposure. This reveals that cocrystals can fine tune the PK profile of meloxicam in order to reduce or enhance exposure.
Two different sulfonate salts, 4-hydroxybenzenesulfonate (p-phenolsulfonate) and 4-chlorobenzenesulfonate, of the anti-spastic agent (R,S) baclofen were developed by strategically interrupting the intramolecularly stabilized zwitterionic structure of baclofen. This zwitterionic structure results in low solubility associated with physiological pH required for intrathecal administration. Structural data for both salts in the form of single crystal X-ray diffraction data was successfully obtained. Solubility based on baclofen was assessed and shown to increase in pure water and at pH's 1 and 7. Only the 4-chlorobenzenesulonate salt maintained an increased solubility over two days at pH 7 making it a viable candidate for further study in terms of intrathecal administration. During crystallization experiments with (R,S) baclofen two polymorphic forms of the baclofen lactam were generated, Forms II and III. Both forms are conformational polymorphs confirmed by single crystal X-ray diffraction and Form II has a Z' of 4 with an unusual arrangement of enantiomers.
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Shi, Baosheng. "Development of an MOF based adsorption air conditioning system for automotive application." Thesis, University of Birmingham, 2015. http://etheses.bham.ac.uk//id/eprint/6017/.
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Metal organic framework (MOF) material is a new class of adsorbent material. This PhD research project set out to investigate the feasibility of an MOF based adsorption air conditioning system for automotive application. To achieve this, utilising a working pair with high refrigerant adsorption capacity and adsorber bed design with good heat and mass transfer performance was investigated. CPO-27Ni is the promising adsorbent. A finite element model was developed to evaluate the adsorption performance of adsorption bed. The rectangular finned tube adsorption bed was found to outperform the other designs. A lab-scale test facility, based on a single bed refrigeration cycle containing one adsorber bed and one heat exchanger, used as both the evaporator and condenser, was constructed. The effects of various operating conditions on the system’s performance were experimentally investigated using this test facility. A lumped-parameter mathematical simulation technique was developed to simulate the working process of the automotive adsorption air conditioning system based on a two-bed system capable of continuous cooling. The performance of the adsorption cooling system was investigated using this mathematical model. The results show that this adsorption air conditioning system can produce the required cooling capacity of 2.39kW, with specific cooling power (SCP) of 440W/kg and coefficient of performance (COP) of 0.456, when a desorption temperature of 130°C is obtained by hot oil heated by the engine’s exhaust gas.
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Kothari, Manish. "Rate independent crystal plasticity." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/36611.
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McMahon, Jennifer Anne. "Crystal engineering of novel pharmaceutical forms." [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001792.
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Lusi, Matto. "Solid state reactions in crystal engineering." Thesis, University of Bristol, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.508123.
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Hughes, Deirdre Patricia. "Versatile building blocks in crystal engineering." Thesis, Queen's University Belfast, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263398.
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Alshgari, Razan. "Crystal engineering of palladium terpyridine complexes." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/47726/.
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The ability of 2,2':6',2"-terpyridine (terpy) to chelate to a wide variety of metal ions has led to the synthesis of different metal-terpyridine complexes. In addition, there are different synthetic strategies have been improved, allowing 2,2':6',2"-terpyridine and its derivatives to find a wide range of applications assensors and catalysts. This thesis concerns the synthesis of a series of Pd(terpy) complexes with different para- and meta-substituted pyridine ligands and their properties are studied by X-ray crystallography. In order to extend the experimental observations and the range of applicability of the proposed interpretation, another system involving the tridentate aromatic nitrogen donor 4,4',4''-tri-tert-butyl-2,2':6',2''-terpyridine (tBu3-terpy) has been examined. A range of N,N-bidentate ligandsare introduced in next section. These can be potentially used to bridge two metal centres. The reactivity of [Pd(terpy)(NCCH3)](CF3SO3)2 was investigated with a wide range of N,N-bidentate ligands. Substitution of the acetonitrile ligand of [P(terpy)(NCCH3)](CF3SO3)2 with these ligands was found to be efficient and facile with reactions occurring at room temperature. Extension of this reaction to meso-tetra (4-pyridyl)porphyrin results in tetranuclear Pd(terpy) complex and affords [{Pd(terpy)}4(H2T(4-Py)P)](CF3SO3)8. In Chapter 6, similarly to terpyridine, 2-phenyl-4,6-bis(2-pyridyl)-1,3,5-triazine (pbptz) is coordinated to palladium as a tridentate ligand and no complex was seen to adopt any of the other potential binding modes for this molecule.
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Noro, Shinichiro. "Crystal engineering of functional coordination polymers." 京都大学 (Kyoto University), 2003. http://hdl.handle.net/2433/148839.
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Amombo, Noa Francoise Mystere. "Crystal engineering of selected phenolic acids." Thesis, Cape Peninsula University of Technology, 2014. http://hdl.handle.net/20.500.11838/734.
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Thesis submitted in fulfilment of the requirements for the degree
Master of Technology: Chemistry
in the Faculty of Applied Science
at the
CAPE PENINSULA UNIVERSITY OF TECHNOLOGY
2014Crystal engineering based upon acid: base compounds have been studied in this thesis. Selected phenolic acids such as: vanillic acid (VA), phenylacetic acid (PAA), 4-hydroxyphenylacetic acid (HPAA), 3-chloro-4-hydroxyphenylacetic acid (CHPAA), caffeic acid (CFA), p-coumaric acid (pCA), trans-ferulic acid (tFER), 2-phenylpropionic acid (PPA) and 2-phenylbutyric acid (PBA) were the main compounds investigated. These phenolic acids have formed co-crystals/co-crystal hydrates, salts/salt hydrates and hybrid salt-co-crystals with acridine (ACRI), caffeine (CAF), cinchonidine (CIND), isonicotinamide (INM), isonicotinic acid (INA), nicotinamide (NAM), quinidine (QUID), quinine (QUIN), theobromine (THBR), theophylline (THPH) and urea (U). The two racemic compounds 2-phenylpropionic acid (PPA) and 2-phenylbutyric acid (PBA) were used to study chiral discrimination leading to the understanding of separation enantiomers. Compounds were prepared in different solvents (alcohols, ketone and distilled water) to investigate the relationship between solvents used and the crystalline product obtained. (If there is any effect on the crystalline compound obtained by changing the solvent). The structures were elucidated using single crystal X-ray diffraction. Ground products of obtained compounds were characterized by powder X-ray diffraction (PXRD). Thermal analyses like thermogravimetry (TG), differential scanning calorimetry (DSC) and hot stage microscopy (HSM) were used for the determination of thermal character of the new compounds. IR was also performed to characterize the new compounds. Non-isothermal TG was utilised to obtain kinetic parameters for the water and the methanol release in (pCA−)(QUIN+)•pCA•MeOH•H2O. A selective experiment was done in which quinidine and quinine were used to compete between selected phenolic acids (PAA and HPAA). viii The comparison of the crystal structures determined showed that, changing the phenolic acid while using the same co-crystal former has a significant effect on the type of compounds obtained. The obtained crystal structures were either co-crystal/co-crystal hydrates, salts/salt hydrates or hybrid salt-co-crystals which formed network via means of supramolecular interactions.
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Dakkama, Hassan Jawdat Fadhiel. "Experimental investigation of MOF adsorption system for ice making, freeze water desalination and cooling applications." Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7837/.
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This work describes the development of Metal Organic Frameworks based adsorption system for producing ice, cooling, ice slurry and potable water using a CP0-27(Ni) and potable/sea water as working pair. Also a novel vacuum based direct freezing technique has been developed in the evaporator of the adsorption ice making system. In this new technique, cooling is generated in the evaporator to produce three outputs, namely, ice, ice slurry and cooling by lowering the freezing point of water using sea salt. The ice and ice slurry are produced in the evaporator during the adsorption-evaporation process, while the cooling process is produced by circulating the water/antifreeze to be cooled in the evaporator. Moreover, the usage of seawater as refrigerant offers producing fresh water as a fourth output in the condenser. A Single and a double bed CP0-27(Ni) MOF adsorption systems were developed to investigate the effect of this novel technique on the system performance in terms of producing of the four outputs. Compared to published literature, the proposed technology showed significantly higher Specific Daily Ice Production of 3 times those reported in literature with additional outputs of ice slurry, cooling and distilled water.
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Clarke, Heather Dawn Marie. "Crystal Engineering of Multi-Component Crystal Forms: The Opportunities and Challenges in Design." Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/4013.
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There is heightened interest to diversify the range of crystal forms exhibited by active pharmaceutical ingredients (APIs) in the pharmaceutical industry. The crystal form can be regarded as the Achilles' heel in the development of an API as it directly impacts the physicochemical properties, performance and safety of the API. This is of critical importance since the crystal form is the preferred method of oral drug delivery by industry and regulatory bodies. The ability to rationally design materials is a lucrative avenue towards the synthesis of functional molecular solids with customized physicochemical properties such as solubility, bioavailability and stability. Pharmaceutical cocrystals have emerged as a new paradigm in pharmaceutical solid form development because they afford the discovery of novel, diverse crystal forms of APIs, generate new intellectual property and modify physicochemical properties of the API. In addition, pharmaceutical cocrystals are amenable to design from first principles of crystal engineering.
This dissertation focuses on the crystal engineering of multi-component crystal forms, in particular pharmaceutical cocrystals and crystalline hydrates. It addresses: (i) the factors involved in the selection of cocrystal formers (ii) design strategies for APIs that exhibit complexity, (iii) the role of water molecules in the design of multi-component crystal forms and (iv) the relationship between the crystal structure and thermal stability of crystalline hydrates.
In general, cocrystal former libraries have been limited to pharmaceutically acceptable substances. It was investigated to expand this library to include substances with an acceptable toxicity profile such as nutraceuticals. In other words, can nutraceuticals serve as general purpose cocrystals formers? The model compounds, gallic acid and ferulic acid, were selected since they possess the functional moieties carboxylic acids and phenols, that are known to form persistent supramolecular synthons with complementary functional groups such as basic nitrogen and amides. The result yielded pairs of cocrystals and revealed the hierarchical nature of hydrogen bonding between complementary functional groups.
In general, pharmaceutical cocrystals have been designed by determining the empirical guidelines regarding the hierarchy of supramolecular synthons. However, this approach may be inadequate when considering molecules that are complex in nature, such as those having a multiplicity of functional groups and/or numerous degrees of conformational flexibility. A crystal engineering study was done to design multi-component crystal forms of the atypical anti-psychotic drug olanzapine. The approach involved a comprehensive analysis and data mining of existing crystal structures of olanzapine, grouped into categories according to the crystal packing exhibited. The approach yielded isostructural, quaternary multi-component crystal forms of olanzapine. The crystal forms consist of olanzapine, the cocrystal former, a water molecule and a solvate.
The role of water molecules in crystal engineering was addressed by investigating the crystal structures of several cocrystals hydrates and their related thermal stability. The cocrystal hydrates were grouped into four categories based upon the thermal stability they exhibit and it was concluded that no structure/stability correlations exist in any of the other categories of hydrate. A Cambridge Structural Database (CSD) analysis was conducted to examine the supramolecular heterosynthons that water molecules exhibit with two of the most relevant functional groups in the context of active pharmaceutical ingredients, carboxylic acids, and alcohols. The analysis suggested that there is a great diversity in the supramolecular heterosynthons exhibited by water molecules when they form hydrogen bonds with carboxylic acids or alcohols. This finding was emphasized by the discovery of two polymorphs of gallic acid monohydrate to it the first tetramorphic hydrate for which fractional coordinates have been determined. Analysis of the crystal structures of gallic acid monohydrate polymorphs revealed that forms I and III exhibit the same supramolecular synthons but different crystal packing and forms II and IV exhibit different supramolecular synthons. Therefore, the promiscuity of water molecules in terms of their supramolecular synthons and their unpredictable thermal stability makes them a special challenge in the context of crystal engineering.
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Field, Simon John. "Ion implanted crystal waveguide lasers." Thesis, University of Southampton, 1992. https://eprints.soton.ac.uk/399433/.
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This thesis reports the first use of He+ implantation to create integrated optic waveguide lasers, by modifying the refractive index of bulk laser host crystals. He+ ion implantation produces a variety of refractive index changes within different target (implanted) crystals which can be used to create planar and channel optical waveguides with propagation losses of the order of 1dB/cm. The spectroscopic properties of the laser impurity dopant in the target crystal are generally not altered drastically by the implantation. The fluorescence lifetime is typically unchanged in the waveguide compared to the bulk crystal, but the fluorescent emission lines are broadened to an extent dependent on the implanted ion dose used to fabricate the waveguide. The wide ranging applicability of the fabrication technique has been demonstrated, with planar waveguide laser action reported in 5 neodymium doped materials, Nd:YAG, Nd:YAP, Nd:MgO:LiNbO3, Nd:Bi4Ge3O12 and Nd:GGG. Diode-pumped laser operation has been demonstrated. with absorbed power thresholds of around 10mW, slope efficiencies up to 30% and output powers up to 40mW. The fabrication of gold ion-stopping masks several microns thick using photolithographic patterning has allowed the creation of the first index enhancement ion implanted channel waveguides, with channel waveguide laser action demonstrated in Nd:YAG and Nd:GGG. Very low laser thresholds of around 500µW absorbed power have been obtained with diode-pumping of Nd:YAG, comparable with the best results achieved with single-crystal fibre growth. Slope efficiencies of 30% have been achieved in both Nd:YAG and Nd:GGG. This thesis also reports the first use of ion implantation to create waveguides in tunable laser crystal hosts, Alexandrite and Cr:YSAG. The spectroscopic properties of the chromium laser impurity are found to be little changed by the waveguide fabrication process, offering hope for the future creation of a tunable channel waveguide laser. In addition, the phenomenon of optically written channel waveguides within ion implanted planar waveguides in Bi4Ge3O12 is reported here. Launching a moderate power (~50mW) laser beam into a He+ implanted planar BGO waveguide creates a permanent channel waveguide structure. Extension of this writing technique to a beam incident on the planar waveguide top surface could allow the production of complex integrated optic circuits, and results of initial experiments of this type are presented.
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Portell, Bueso Anna. "Crystal Engineering Studies of Squaric Acid Derivatives." Doctoral thesis, Universitat de Barcelona, 2014. http://hdl.handle.net/10803/285325.
Full textAbstract:
This thesis is a multidisciplinary study of the solid state of squaric acid derivatives which combines approaches from areas such as crystal engineering, supramolecular chemistry and crystallography. The structural preferences in the solid state of this family of compounds has been analyzed, new crystalline materials derived from squaric acid have been designed in order to study new supramolecular synthons and relevant chemical phenomena such as template effect, preorganization, cooperativity and electrostatic compression have been explored.
In summary, 47 polymorphs, solvates, cocrystals and salts from 22 squaric acid derivative compounds have been obtained and 31 crystal structures have been solved and analyzed. Several experimental techniques such as differential scanning calorimetry, thermogravimetry, thermomicroscopy, NMR spectroscopy and Xray diffraction have been used for the analysis of the squaric acid derivatives synthesized. In this sense, the optimization of a methodology for solving crystal structures from laboratory powder Xray diffraction data by means of direct space methods has permitted to overcome the difficulty of growing good quality single crystals of disecondary squaramides.
Squaramides are interesting compounds due to their double donoracceptor hydrogen bond character. In this work, their structural characteristics in the solid state have been studied and cooperativity in hydrogenbonded catemers has been observed to play a crucial role in defining the robust solidstate headtotail synthon in the anti/anti conformation of disecondary squaramides, overriding the preferred association mode anti/syn observed in solution. Consequently, the selfassembling of the squaramide rings is a very strong binding motif, which has been proven difficult to be perturbed by other competing functional groups in the solid state. Taking into account these characteristics, two different cocrystal design strategies have been developed: the first one considering the preorganization of a monosquaramide ester via intramolecular hydrogen bonding, and the second one, more successful, considering that secondary squaramides can act as molecular scaffolds which, with a suitable functionalization of their substituents, new multicomponent solids have been obtained with coformers interacting via peripheral hydrogen bonding. Moreover, the analysis of the hydrogen bonding donor/acceptor parameters (a and ß) has been conducted with some model compounds with the aim of explaining their structural preferences in the solid state. Understanding the preference of a functional group for a particular synthon is mandatory in order to design new crystalline materials. In this sense, an unprecedented squaramide helical topology driven by the headtotail interaction has been reported, revealing its potential use in the field of crystal engineering and supramolecular chemistry. In a second stage of this thesis, further inside has been given to squaric acid derivatives through the design of zwitterionic squaramides. This has permitted the analysis of the electrostatic compression phenomenon which is responsible for a robust dimeric supramolecular synthon which also allows the formation of multicomponent solids. Finally, a collaborative research has been conducted on the theoretical and experimental of the main interactions shown by squaric acid and amidosquaric acid salts in the solid state.
In summary, it can be concluded that the squaric/squaramide functional group, poorly studied in the solid state, has interesting properties which can be potentially exploited for the design and synthesis of new and diverse crystalline materials.Aquesta tesi presenta un estudi multidisciplinar de l’estat sòlid de derivats de l’àcid esquàric, enmarcat en diferents àrees com l’enginyeria cristal•lina, la química supramolecular i la cristal•lografia. Les esquaramides són compostos interessants per la seva capacitat doble donadora/acceptora d’enllaços d’hidrogen. En aquest treball s’han analitzat les característiques estructurals de les esquaramides en l’estat sòlid i s’han dissenyat nous materials cristal•lins derivats de l’àcid esquàric per tal d’estudiar nous sintons supramoleculars. L’estudi de la capacitat acceptora/donadora de compostos model a través de la determinació teòrica dels paràmetres d’enllaç d’hidrogen (a i ß), ha permès la racionalització dels aspectes estructurals d’aquesta família de compostos. A més, a través d’aquest estudi, s’han explorat fenòmens químics de rellevància com l’efecte template i la preorganització pel disseny de sals i cocristalls, la cooperativitat, responsable del sintó observat en estat sòlid de les diesquaramides secundàries, així com la compressió electrostàtica identificada en esquaramides zwitteriòniques i sals de l’àcid esquàric. En resum s’han obtingut 47 polimorfs, solvats, cocristalls i sals de 22 derivats de l’àcid esquàric i s’han resolt i analitzat 31 estructures cristal•lines. Per a l’anàlisi de les espècies sintetitzades s’han utilitzat diferents tècniques experimentals com la calorimetria diferencial d’escaneig, la termogravimetria, la termomicroscòpia, l’espectroscòpia de ressonància magnètica nuclear i la difracció de raigs X de pols i de monocristall. En aquest sentit, l’optimització de la metodologia de resolució d’estructures cristal•lines a partir de dades de difracció de raigs X de laboratori a través de mètodes d’espai directe ha permès superar les dificultats que presenten les esquaramides secundàries a cristal•litzant monocristalls de qualitat. A partir dels resultats d’aquesta tesi doctoral es pot concloure que el grup funcional esquàric/esquaramida, poc estudiat en l’estat sòlid, té unes propietats potencialment explotables en el disseny i la síntesi de nous i diversos materials cristal•lins.
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Bis, Joanna A. "Crystal engineering of organic compounds including pharmaceuticals." [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001424.
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Bridgland, Lydia Naomi. "Crystal engineering of porous steroidal organic crystals." Thesis, University of Bristol, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.627972.
Full textAbstract:
Porous materials are highly valued for a wide variety of scientific and technological applications and organic molecular crystals offer an alternative to established inorganic materials. In this thesis, the porosity of tris-N-phenylureido steroidal crystals IS characterised and the versatility of the steroidal crystal system is demonstrated. Material properties can often be adjusted by mixing components in varying proportions to form alloys, but this phenomenon is rarely demonstrated for organic molecules. In organic crystals, molecules pack into an array which has symmetry and dimensions specific to the compound. Thus, in general, molecules cannot be substituted for molecules of a different compound. The studies presented here demonstrate that organic alloys are possible if the crystal structure possesses voids which are able to accommodate significant p0l1ions of the new molecules. A variety of multi-component steroidal crystals have been created with diverse and complex channel interiors. These have been characterised by optical microscopy, single X-ray crystallography, IH NMR and mass spectrometry. Finally, molecular machines which perform mechanical work on a molecular level are of great interest within the scientific community. The operational range of molecular motion is often too restricted to create macroscopic phenomena, but by confining the molecular machines to small spaces such as nanopores, molecular movement on the nanometre level can be sufficient to dominate the physical and chemical behaviour of guest molecules. In this thesis, the prospect of creating a new type of molecular machine assembly to propel molecules unidirectionally along crystal channels has been investigated. Crystal engineering has been used to design porous steroidal crystals with azobenzene moieties, capable of photoinduced isomerisation, protruding into the crystal channels. The resulting crystals have been analysed by optical microscopy and solid-state UV-vis spectroscopy, and the distribution of guest molecules within the crystals has been investigated by Raman and IR microspectroscopy and fluorescence microscopy.
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Ong, Tien Teng. "Crystal Engineering of Molecular and Ionic Cocrystals." Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3270.
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Solubility enhancement of poorly-soluble active pharmaceutical ingredients (APIs) remains a scientific challenge and poses a practical issue in the pharmaceutical industry. The emergence of pharmaceutical cocrystals has contributed another dimension to the diversity of crystal forms available at the disposal of the pharmaceutical scientist. That pharmaceutical cocrystals are amenable to the design principles of crystal engineering means that the number of crystal forms offered by pharmaceutical cocrystals is potentially greater than the combined numbers of polymorphs, salts, solvates and hydrates for an API. The current spotlight and early-onset dissolution profile ("spring-and-parachute" effect) exhibited by certain pharmaceutical cocrystals draw attention to an immediate question: How big is the impact of cocrystals on aqueous solubility? The scientific literature and in-house data on pharmaceutical cocrystals that are thermodynamically stable in water are reviewed and analyzed for trends in aqueous solubility and melting point between the cocrystal and the cocrystal formers. There is poor correlation between the aqueous solubility of cocrystal and cocrystal former with respect to the API. The log of the aqueous solubility ratio between cocrystal and API has a poor correlation with the melting point difference between cocrystal and API. Structure-property relationships between the cocrystal and the cocrystal formers remain elusive and the actual experiments are still necessary to investigate the desired physicochemical properties.
Crystal form (cocrystals, polymorphs, salts, hydrates and solvates) diversity is and will continue to be a contentious issue for the pharmaceutical industry. That the crystal form of an API dramatically impacts its aqueous solubility (a fixed thermodynamic property) is illustrated by the histamine H2-receptor antagonist ranitidine hydrochloride and HIV protease inhibitor ritonavir. For more than a century, the dissolution rate of a solid has been shown to be directly dependent on its solubility, cçterîs paribus. A century later, it remains impossible to predict the properties of a solid, given its molecular structure. If delivery or absorption of an API are limited by its aqueous solubility, aqueous solubility then becomes a critical parameter linking bioavailability and pharmacokinetics of an API. Since the majority of APIs are Biopharmaceutical Classification System (BCS) Class II (low solubility and high permeability) compounds, crystal form screening, optimization and selection have thus received more efforts, attention and investment. Given that the dissolution rate, aqueous solubility and crystal form of an API are intricately linked, it remains a scientific challenge to understand the nature of crystal packing forces and their impact upon physicochemical properties of different crystal forms. Indeed, the selection of an optimal crystal form of an API is an indispensable part of the drug development program. The impact of cocrystals on crystal form diversity is addressed with molecular and ionic targets in ellagic acid and lithium salts. A supramolecular heterosynthon approach was adopted for crystal form screening. Crystal form screening of ellagic acid yields molecular cocrystals, cocrystal solvates/hydrates and solvates. Crystal form screening of lithium salts (chloride, bromide and nitrate salts) afforded ionic cocrystals and cocrystal hydrates.
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Petr, Michael Thomas. "Photo-responsive liquid crystal block copolymers/." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/76356.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2012.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
"June 2012." Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (p. 100-108).
Photo-responsive liquid crystal polymers (LCP) which contain azobenzene moieties have gained interest for their ability to change properties by merely irradiating them with the correct wavelength of light in the appropriate temperature range. Furthermore, they have been crosslinked for elasticity and to translate this property change into photo-mechanical actuation, such as contraction, expansion, bending, or oscillation. However, a major drawback and hindrance to their actual use as actuators has been their need for elevated temperatures and their slow responses at room temperature. The work described in this thesis addresses this problem, and its solution has an impact on the field of functional elastomers in general. To produce a fast photo-response at room temperature, a new photo-responsive azobenzene nematic side chain (SC) LC polysiloxane was developed, characterized, and demonstrated to respond significantly, and reversibly from 0-50°C, which is the ambient temperature range in which we live, through its photo-induced nematic to isotropic transition. In particular, its nematic phase almost totally disappeared in 35 s, and its modulus decreased up to 35% in about 10 s. To turn this photo-response into photo-actuation, polystyrene (PS) end blocks were added to the poly(vinylmethylsiloxane) (PVMS) to produce PS-b-PVMS-b-PS, which is important in and of itself because the PVMS has a very low Tg and a functionalizable backbone and the PS end blocks make the material a thermoplastic elastomer. After attachment of the azobenzene LC, the resulting photo-responsive thermoplastic elastomer reversibly contracted 3.3% against 25.7 kPa of stress in about 6 s.
by Michael Thomas Petr.
Ph.D.
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Segersäll, Mikael. "Nickel-Based Single-Crystal Superalloys : the crystal orientation influence on high temperature properties." Licentiate thesis, Linköpings universitet, Konstruktionsmaterial, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-89950.
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Superalloys are a group of materials that are used in high temperature applications, for example gas turbines and aero engines. Gas turbines are most commonly used for power generation, and it is only the very critical components which are exposed to the most severe conditions within the turbine, which are made from superalloy material. Today, energy consumption in many parts of the world is very high and is tending to increase. This implies that all power generating sources, including gas turbines, must aim for higher efficiency. For the gas turbine industry, it is a continuous challenge to develop more energy-efficient turbines. One way to do this is to increase the temperature within the hot stage of the turbine. However, increased temperature in the hot stage also challenges the materials that are used there. Today’s materials are already pushed to the limit, i.e. they cannot be exposed to the temperatures which are required to further increase the turbine efficiency. To solve this problem, research which later can lead to better superalloys that can withstand even higher temperatures, has to be conducted within the area of superalloys. The aim of this licentiate thesis is to increase our knowledge about deformation and damage mechanisms that occur in the microstructure in superalloys when they are subjected to high temperatures and loads. This knowledge can later be used when developing new superalloys. In addition, increased knowledge of what is happening within the material when it is exposed to those severe conditions, will facilitate the development of material models. Material models are used for FEM simulations, when trying to predict life times in gas turbine components during the design process. This licentiate thesis is based on results from thermomechanical fatigue (TMF) testing of Ni-based single-crystal superalloys. Results show that the deformation within the microstructure during TMF is localized to several deformation bands. In addition, the deformation mechanisms are mainly twinning and shearing of the microstructure. Results also indicate that TMF cycling seems to influence the creep rate of single-crystal superalloys.
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Wang, Siping S. M. Massachusetts Institute of Technology. "Gallium Nitride phononic crystal resonator." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/99831.
Full textAbstract:
Thesis: S.M., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2015.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 41-42).
We present a Gallium Nitride (GaN) Lamb Wave resonator using a Phononic Crystal (PnC) to selectively confine elastic vibrations with wide-band spurious mode suppression. A unique feature of the design demonstrated here is a folded PnC structure to relax energy confinement in the non-resonant dimension and to enable routing access of piezoelectric transducers inside the resonant cavity. This provides a clean spectrum over a wide frequency range and improves series resistance relative to transmission line or tethered resonators by allowing a low-impedance path for drive and sense electrodes. GaN resonators are demonstrated with wide-band suppression of spurious modes, f -Q product up to 3.06 x 1012, and resonator coupling coefficient k2.eff up to 0.23%. (filter BW up to 0.46%). Furthermore, these PnC GaN resonators exhibit record-breaking power handling, with IIP3 of +27.2dBm demonstrated at 993MHz.
by Siping Wang.
S.M.
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Uthman, Muhammad. "Finite element characterisation of photonic crystal fibres." Thesis, City University London, 2013. http://openaccess.city.ac.uk/3012/.
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Rigorous numerical simulations have been carried out by using the Finite Element Method (FEM) in order to calculate bending and leakage losses of Photonic Crystal Fibres (PCF). A modal solution approach including the implementations of the conformal transformation and the Perfectly Matched Layer (PML) were undertaken to determine the bending and leakage losses of several designs of Photonic Crystal Fibres. This was carried out by varying key parameters such as the pitch (Λ), diameter (d) and air-filling fraction (d/Λ). Output modal parameters including the effective indices, spot sizes, leakage and bending losses as well as the mode field profiles were obtained. These output parameters were obtained by varying the bending radius (R) from very large values to very low values for different dimensions of the PCF, with results being obtained for Transverse Magnetic and Transverse Electric (quasi-TM and quasi-TE) polarizations. These parameters were calculated by solving the Maxwell’s equations using the H-field vector formulation and with the inclusion of PML to solve complex eigenvalue equations. Generally, it was observed that for all Λ, d/Λ and the polarization considered, as R is reduced from a very high value to lower values, the bending losses increase and there is a sharp increase at some lower values of R. At some very low values of R, some oscillatory behaviour was observed in the curves obtained for the fibre losses, where further investigations were carried out. These oscillations appeared due to degeneration of the fundamental mode with the cladding modes. In most of the cases investigated, there was a correlation in the variation of effective indices the loss values and also in the variation of spot sizes. PCFs with non-identical air-holes were also investigated in which case the d ≠ d2 (diameter of 4 larger air-holes in the first ring) and knowing the values for TM and TE polarizations, it was possible to determine the birefringence, which is the difference between the effective indices for the TM and TE modes and also the loss ratio, which is the ratio of TM loss to that of the TE loss. All the input and output parameters that were considered with the symmetric air-holes were also considered in the case with fibre with asymmetric air-holes study. The results obtained are very important in the design of Single Mode Single Polarization PCF. Results have also been obtained from the studies done of asymmetric arrangement of air-holes which lead to the design of Single Mode Single Polarization PCF. Work was carried out on the design of a tapered PCF that could be efficiently coupled to a single mode fibre, SMF. This was achieved by increasing the number rings up to 10 rings of air-holes in the cladding and having the outermost ring with larger air-holes, the inner rings were near cutoff. This fibre was coupled to a conventional SMF to allow for better tolerance to fabrication errors. There has also been work carried out in polymer fibre namely Teflon and TOPAS in the terahertz regime. The conventional hexagonal arrangement of PCF was simulated and compared to spiral PCF in THz. An improved PCF design having a porous core with hexagonal arrangement and cladding was designed and analysed and low-loss guidance in THz was achieved. Thus overall a number of different PCF designs were considered and their properties evaluated and detailed knowledge has been obtained on potential performance of such fibres.
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Kabir, Saiful. "Finite element modelling of photonic crystal fibres." Thesis, City University London, 2007. http://openaccess.city.ac.uk/8592/.
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Photonic crystal fibre (PCF), a new kind of optical fibre, has many air-holes in their cross-section and has potential applications to new optical communication systems. The main objective of this research is the modelling of photonic crystal fibre to identify the fundamental and higher order quasi-TE and TM modes with square, ,rectangular and circular air holes in a square and hexagonal matrix, by using a rigorous full-vectorial H-field based finite element method (FEM). Besides the modal solutions of the effective indices, mode field profiles, spot sizes, modal hybridness, polarization beat length and group velocity dispersion values for equal and unequal air holes; research was carried out to optimize and design highly birefringent PCF. The variation of modal birefringence is shown through the effect of hole diameters, air hole arrangement, structural asymmetry, operating wavelength, and pitch-distance. Birefringence was enhanced by breaking the structural symmetry and this was verified by using unequal air holes. The diameter of two air holes and four air holes in the first ring was changed to break the rotational symmetry and a comparison between the two designs is made in this work. In this work, highly birefringent PCF is designed with higher operating wavelength, larger d2/A value, lower pitch length for a given structural asymmetry. It is identified that birefringence value increases rapidly when d2 is much larger than d. At lower pitch value, one of the highest birefringence values reported so far at wavelertgth of 1.55 J.Jm for an asymmetric PCF using circular air holes. A single polarization guide PCF structure is also achieved. In this study, it has been identified that for fixed d/A and d2/A value, as operating wavelength is increased, birefringence increases significantly. It can also be identified that for higher d/A values, birefringence changes rapidly with A as their corresponding cutoff condition also approaches. One important validation of this work is the existence of modal birefringence for PCF with six-fold rotational symmetry. It is shown that birefringence value of a simple PCF incorporating circular holes but of different diameters is high compared to polarization maintaining Panda or Bow-tie fibres. This research also aims to investigate the modal leakage losses of PCF, by using a semi-vectorial beam propagation method (BPM) based on the versatile FEM. The robust perfectly matched layer (PML) boundary condition has been introduced to the modal solution approach. The effects of d2/A, operating wavelength and number of air holes have been thoroughly detailed and explained. In this study, it has been identified that the confinement loss decreases significantly with the increased number of rings, lower operating wavelength and lower d2/A value. For special case, PCF with large spot-size provides higher leakage loss.
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Ahmed, Sayima J. "Crystal engineering of pharmaceutical salts and co-crystals." Thesis, University of Reading, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.515715.
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Harrington, Ross William. "Hydrogen bond directed crystal engineering of metal complexes." Thesis, University of Bath, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.393831.
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Nieuwenhuyzen, Mark. "Crystal engineering and polymorphism : aspects of hydrogen bonding." Thesis, Queen's University Belfast, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301029.
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Silva, Benjamin M. de. "Crystal engineering of bipyridyl ligands in coordination networks." Thesis, University of Aberdeen, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.430025.
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A number of bipyridyl compounds containing amide functionalities have been prepared as bridging bipyridyl ligands in coordination networks. The bridging ability and hydrogen bond donor-acceptor functionality of these compounds in coordination networks has been explored by their inclusion in crystallisation experiments containing a single salt from a variety of d block metal salts, with ethanol and water as the solvent. The crystal structures of the coordination network polymers of [Cd L2 (H2O)2]2/∞ 2NO3 (L = N,N’-bis(3-pyridylmethyl)urea), [Cu L2 (NO3)2]2/∞ . 2H2O .2EtOH (L = N,N’-bis(3-pyridylmethyl)urea), [Cd L2 (NO3) (H2O)]1/∞ . NO3 . H2O (L = N,N’-bis(4-pyridylmethyl)urea), [Cu L2 (NO3) (H2O)]1/∞ . NO3 . H2O (L = N,N’-bis(4-pyridylmethyl)urea), [Cd3 L4 (H2O)8 (H2O)8 (SO4)2]1/∞ . 4H2O . SO4 (L = N,N’-bis(4-pyridylmethyl)urea), [Cu L (OAc)2]1/∞ (L = N,N’-bis(4-pyridylmethyl)urea), [Cu2 L2 (NO3)4 (BIPY)2 (H2O)3/1/∞ . H2O (L = N,N’-bis(4-pyridylmethyl)isophthalamide), (BIPY = 2,2’-bipyridine) and [Cu L2 2(H2O)]1/∞. 2(H2O) . 2(CIO4)2 (L = N,N’-bis(3-pyridylmethyl)succinamide) are described. Wittig reaction conditions, followed by hydrogenation are used for the preparation of a number of saturated bipyridyl compounds possessing an additional aromatic functionality. The bridging ability of these ligands has been explored by their inclusion in crystallisation experiments containing a single salt from a variety of d block metal salts, with ethanol and water as the solvent. The crystal structures of the coordination polymers of [Cd L2 (NO3)2]2/∞ (L = 1,2-bis[2-(3-pyridyl)ethyl]benzene), [Cd L2 (H2O)2 (CIO4)2]2/∞ (L = 1,2-bis[2-(3-pyridyl)ethyl]benzene), [Cu1.5 L2 (NO3) (H2O)2]2/∞ . 2(NO3) . 2.7(H2O) (L = 3,5-bis[2-(4-pyridyl)ethyl]pyridine) and [Cd2 L5 (H2O)4]1/∞ . L . 2H2O . 2EtOH . 4CIO4 (L = 1,4-bis[2-(4-pyridyl)ethyl]benzene) are described.
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Gillon, Amy Louise. "Structural and crystal engineering studies of metal complexes." Thesis, University of Bristol, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340299.
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Tandon, Sheila (Sheila N. ). 1978. "Engineering light using large area photonic crystal devices." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/33931.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.Includes bibliographical references.
Photonic crystals are fabricated structures composed of a periodic arrangement of materials with differing indices of refraction. This research has focused on the realization of two distinct photonic crystal structures in which large area has played a key role: 1) large area broadband saturable Bragg reflectors, and 2) large area 2D photonic crystal devices. Saturable Bragg reflectors (SBRs) can be used to self-start ultra-short pulse generation in a variety of solid state and fiber lasers. To form shorter pulses, SBRs with broadband reflectivity and large area (100's of [mu]m) are required. This thesis describes the design and fabrication of large area broadband saturable Bragg reflectors through the monolithic integration of semiconductor saturable absorbers with large area broadband Bragg mirrors. One of the key elements for realizing this device is the development of a wet oxidation process to create buried low-index ... layers over large areas. Large area 2D photonic crystals enable new methods for routing and guiding light with applications in compact integrated optical circuits. This research has explored the design and fabrication of two large area (centimeter-scale) 2D photonic crystal devices: a superprism and a super- collimator.
(cont.) A superprism is a photonic crystal device in which the direction of light propagation is extremely sensitive to the wavelength and angle of incidence. A super- collimator is a device in which light is guided by the dispersion properties of a photonic crystal slab without boundaries which define the light's path. Design, fabrication, and testing are discussed for both 2D photonic crystal devices.
bu Sheila N. Tandon.
Ph.D.
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McKellar, Scott Campbell. "Crystal engineering approaches to solid-state pharmaceutical systems." Thesis, University of Strathclyde, 2012. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=18024.
Full textAbstract:
Control of a solid drug's physical form is an important stage of drug development, in order to best optimise the physicochemical properties of the drug. It is also important for intellectual property and regulatory considerations. Commonly, optimisation of a solid drug form moves beyond controlling the solid-state and actively manipulating it, via salt formation, co-crystal synthesis or inclusion complexation, for example. Presented in this work are three distinct approaches to the control and development of solid-state form of organic molecules and pharmaceuticals. The first of these approaches reports a novel, relatively simple technique for polymorph screening of compounds that are thermally stable, wherein homopolymer surface interactions direct the polymorph of a drug recrystallising from the supercooled melt. The study carried out demonstrates the ability to selectively crystallise the a polymorph of indomethacin using specific polymer substrates. The second theme details a crystal engineering strategy for a drug molecule to obtain a novel solid form. It is shown how knowledge of intermolecular hydrogen bonded supramolecular synthons can be exploited to rationally select potential co-crystal formers based on the likely growth unit formed. The structure of the co-crystal, solved using single-crystal X-ray diffraction, is reported and verifies the design strategy. The potential to enhance a drug's properties is demonstrated by an increased melting point compared to the native drug form, such that the liquid drug becomes a stable solid at room temperature. There is also an improved intrinsic dissolution rate as a direct result of the application of the methodology. In the last chapter, a systematic structural investigation of cyclodextrin inclusion complexes with an isomeric series of guest molecules has generated a large number of single-crystal structures and X-ray powder diffraction patterns. These provide structural understanding of these systems and highlight isostructural trends that can be used to make some general structural predictions. A heavy emphasis is placed on the method used to synthesise the crystalline inclusion complex and the structural role of cosolvents. A complementary solution-state investigation was also performed to detail the solution-state chemistry of these systems and enable the relationship between solution-state and solid-state complexation to be investigated.
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Adler, Philip David Felix. "Crystalline cheminformatics : big data approaches to crystal engineering." Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/410940/.
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Statistical approaches to chemistry, under the umbrella of cheminformatics, are now widespread - in particular as a part of quantitative activity structure relationship and quantitative property structure relationship studies on candidate pharmaceutical studies. Using such approaches on legacy data has widely been termed “taking a big data approach”, and finds ready application in cohort medicinal studies and psychological studies. Crystallography is a field ripe for these approaches, owing in no small part to its history as a field which, by necessity, adopted digital technologies relatively early on as a part of X-ray crystallographic techniques. A discussion of the historical background of crystallography, crystallographic engineering and of the pertinent areas of cheminformatics, which includes programming, databases, file formats, and statistics is given as background to the presented research. Presented here are a series of applications of Big Data techniques within the field of crystallography. Firstly, a naıve attempt at descriptor selection was attempted using a family of sulphonamide crystal structures and glycine crystal structures. This proved to be unsuccessful owing to the very large number of available descriptors and the very small number of true glycine polymorphs used in the experiment. Secondly, an attempt to combine machine learning model building with feature selection was made using co-crystal structures obtained from the Cambridge Structural Database, using partition modelling. This method established sensible sets of descriptors which would act as strong predictors for the formation of co-crystals, however, validation of the models by using them to make predictions demonstrated the poor predictive power of the models, and let to the uncovering of a number of weaknesses therein. Thirdly, a homologous series of fluorobenzeneanilides were used as a test bed for a novel, invariant topological descriptor. The descriptor itself is based from graph theoretical techniques, and is derived from the patterns of close-contacts within the crystal structure. Fluorobenzeneanilides present an interesting case in this context, because of the historical understanding that fluorine is rarely known to be a component in a hydrogen bonding system. Regardless, the descriptor correlates with the melting point of the fluorobenzeneanilides, with one exception. The reasons for this exception are explored. In addition, a comparison of categorisations of the crystal structure using more traditional “by-eye” techniques, and groupings of compounds by shared values of the invariant descriptor were undertaken. It is demonstrated that the novel descriptor does not simply act a proxy for the arrangement of the molecules in the crystal lattice- intuitively similar structures have different values for the descriptor while very different structures can have similar values. This is evidence that the general trend of exploring intermolecular contacts in isolation from other influences over lattice formation. The correlation of the descriptor with melting point in this context suggests that the properties of crystalline material are not only products of their lattice structure. Also presented as part of all of the case studies is an illustration of some weaknesses of the methodology, and a discussion of how these difficulties can be overcome, both by individual scientists and by necessary alterations to the collective approach to recording crystallographic experiments.
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Tahier, Tayyibah. "Crystal engineering of mixed-ligand metal-organic frameworks." Master's thesis, University of Cape Town, 2016. http://hdl.handle.net/11427/22913.
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Research of solid state complexes has grown and developed exponentially over the past few years in terms of supramolecular chemistry and crystal engineering. The synthesis and characterisation of metal organic frameworks (MOFs) have attracted widespread attention owing to their potential in various applications. This includes gas sorption, which could aid in alleviating serious environmental issues such as global warming by sequestrating greenhouse gases. Advances in the design of these materials using the mixed ligand approach add to variation in structures and thus provide a further means of tailoring of properties. A novel two dimensional, mixed ligand MOF has been synthesised based on 1,3,5 benzenetricarboxylic acid, 4,4' bipyridine N,N' dioxide and zinc sulfate with the formula [Zn3(BTC)(4,4' bpdo)(OH)(SO4)(H2O)3]n·n(H2O)2.33 (1). The 2D layers of 1 arrange in a polar fashion with adjacent layers forming isolated cavities. Variable temperature powder X ray diffraction (VT PXRD) analysis showed that the crystallinity of the compound was retained and the crystalline phase remained unchanged as the temperature was increased. Variable temperature single crystal X ray diffraction (VT SCXRD) analysis of 1 revealed that the dehydration and rehydration processes occur via single crystal to single crystal transformations. Water vapour sorption experiments showed a type I isotherm, typical of microporous materials. A two dimensional, interpenetrated, mixed ligand MOF has been synthesised based on 5 nitro 1,3 benzenedicarboxylic acid, 1,2 bis(4 pyridyl)ethane and cadmium nitrate with the formula [Cd(bpe)1.5nbdc]·DMF (2). VT PXRD analysis shows subtle differences in the compound as the temperature is increased. VT SCXRD experiments show that the most notable change in the structure occurs at 373 K. These changes include the removal of the guest molecule and a change in the crystal system, along with changes in the orientation of the pyridyl ring of the organic ligand. Carbon dioxide sorption experiments at 195 K showed a type IV isotherm, which is usually associated with mesoporous materials. Both 1 and 2 were synthesised using the solvothermal method and fully characterised using X ray diffraction studies (SCXRD, PXRD, VT SCXRD and VT PXRD), thermal analysis (thermogravimetric, differential scanning calorimetry, hot stage microscopy), elemental analysis and FT IR spectroscopy. The porosity of the compounds was tested using carbon dioxide (273 K and 193 K), nitrogen, water vapour and liquid sorption experiments.
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Jadav, Niten B. "Novel Technology for Crystal Engineering of Pharmaceutical Solids." Thesis, University of Bradford, 2018. http://hdl.handle.net/10454/18177.
Full textAbstract:
The research work described in this thesis, the environmentally
friendly novel "Microwave Assisted Sub-Critical water (MASCW)" technology
for particle engineering of active pharmaceutical ingredients and excipients
was developed. The present novel technology MASCW process is described
as green technology as water is used as the solvent medium and microwave
energy as external source of heat energy for generation of a particle with
different morphological and chemical properties.
In MASCW process supersaturated solution of APIs is prepared by
dissolving solute in water at high temperature and pressure conditions. Upon
rapid and controlled cooling, based on the aqueous solubility of solute,
solute/solvent concentration and dielectric constant of water rapid
precipitation of API with narrow particle size distribution occurs.
Using paracetamol (pca) as API moiety understanding of the
mechanism of MASCW crystallisation process was investigated. The effect
of different process and experimental parameters on crystallisation pathway
and end product attributes were analysed. Correlation between the degree of
supersaturation concentration of pca solution against temperature and
pressure parameters was explained by generating binary phase diagram.
Determination of polymorphic transformation pathway of pca from form I
(stable) to form II metastable polymorphs in solution was analysed using Raman spectroscopy. The difference between conventional heating and
subcritical treatment was explored by determining the change in the solvent
dielectric constant and solubility of hydrophobic API molecule.
Based on the process understanding results, this technology was
further implemented to explore its application in generating phase pure
stable and metastable cocrystal phase. Based on the solubility of API and
cocrystal former congruent (CBZ/SAC, SMT/SAC, SMZ/SAC) and
incongruent (CAF/4HBA) cocrystal pairs were selected. For the first time
generation of anhydrous phase of CAF: 4HBA cocrystal in 1:1 stoichiometric
ration was reported and generation of metastable cocrystal phase of CA
CBZ: SAC form II was reported.
The application of this technology was explored in generating phase
pure metastable polymorph of paracetamol which retain higher
compressibility and dissolution rate. The potential of MASCW micronisation
process, theophylline is used as the model component to produce micro sized particles for pulmonary drug delivery system via dry powder inhaler
(Foradil inhaler). The results demonstrate that the THF particles generated
using MASCW process displayed greater aerodynamic performance
compared to conventional spray-dried THF sample.
In the final chapter, synthesis of inorganic biomaterial (nano crystalline hydroxyapatite) was reported for the first time and the prospects of
combining API like ibuprofen (IBU) with a biologically active component like
nano-crystalline hydroxyapatite (HA) through hydrogen bonding was
mechanistically explained using X-ray diffractometer and spectroscopic
techniques.The full text will be available at the end of the embargo: 16th May 2021
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Morales, Leslie Ann. "Crystal Engineering of Binary Compounds Containing Pharmaceutical Molecules." [Tampa, Fla.] : University of South Florida, 2003. http://purl.fcla.edu/fcla/etd/SFE0000166.
Full text
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Lu, Jianjiang. "Crystal engineering of metal-carboxylate based coordination polymers." [Tampa, Fla.] : University of South Florida, 2004. http://purl.fcla.edu/fcla/etd/SFE0000361.
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Kershaw, Cook Laurence Jonas. "Crystal engineering and bifunctionality in spin-crossover materials." Thesis, University of Leeds, 2014. http://etheses.whiterose.ac.uk/7760/.
Full textAbstract:
This thesis focuses on crystal engineering metal salts of 2,2’:6’,2’’-terpyridine and 2,6-di(pyrazol-1’-yl)pyridine to tune and better understand the cooperative spin crossover in the solid state and incorporation of a second functionality towards bifunctional spin crossover materials. Chapter 1 can be considered an introduction to the phenomenon of spin crossover in first row transition metal complexes and outlines its discovery, recent developments and progression towards real-world application. Chaper 2 is a discussion of the methodology of synthetic efforts undertaken in the acquisition of the wealth of tris-chelating organic compounds whose coordination chemistry is the subject of later chapters. Chapter 3 details the spectroscopic, electrochemical and magnetic properties of cobalt(II) and iron(II) complexes of tris-azinyl analogues of 2,2’:6’,2’’-terpyridine in efforts towards tuning their electronic spin-equilibria. Chapter 4 presents a series of novel ruthenium(II) based materials exhibiting enhanced room temperature emission and their incorporation into an inert spin crossover host material. Retention of parent functionalities is screened for over an operable temperature regime. Chapter 5 concerns iron(II) complex salts of 2,6-di(pyrazol-1’-yl)pyridine derivatives, whose ligand backbones are modified in an attempt to tune the solid state spin crossover behaviour both electronically and sterically. Chapter 6 is an account of all synthetic procedures carried out during this work, their standard characterisation and details the instrumentation performed on all materials which are the subject of discussion in this thesis.
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Paisner, Kathryn A. 1983. "Crystal Engineering with Thioureas: A Structure-Based Inquiry." Thesis, University of Oregon, 2011. http://hdl.handle.net/1794/11583.
Full textAbstract:
xviii, 724 p. : ill. (some col.)Structural trends applicable to crystal engineering were studied in three classes of thiourea-based compounds. The aim of the study was to identify, predict, and ultimately design reliable single-molecule structural features, which could then be used to engineer crystals with desirable properties. In one class of compounds, this goal was achieved: N-alkyl and N-aryl derivatives of N,N'-bis(3-thioureidopropyl)piperazine adopted an identical conformation in the solid state, which resulted in near-identical crystal packing. A second class of closely related compounds, N-substituted tris(2-thioureidoethyl)amines, showed no such reliability in the solid state, likely because the parent structure lacked hydrogen-bonding functionalities sufficient to control intramolecular structure. In the third class of compounds that we studied, 1-benzoyl-3-(2-pyridyl)thioureas, substitution patterns were often predictive of molecular conformation; however, these intramolecular trends did not lead to recognizable crystal packing motifs. Nevertheless, certain physical properties observed in this last class of compounds--color, solubility, and often crystallinity--were conformer-specific, interestingly without any apparent relevance to crystal lattice structure. Solution-state and solid-state conformational trends in these 1-benzoyl-3-(2-pyridyl)thioureas have been documented, and speculations as to the source of color in one of the two observed conformations have been noted.
Committee in charge: Shih-Yuan Liu, Chairperson; Kenneth M. Doxsee, Advisor; Michael M. Haley, Member; Catherine J. Page, Member; Paul J. Wallace, Outside Member
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Pfrunder, Michael Craig. "Halogen bond mediated crystal engineering of metal complexes." Thesis, Queensland University of Technology, 2014. https://eprints.qut.edu.au/71083/1/Michael_Pfrunder_Thesis.pdf.
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This project explored the potential for halogen bonds to predictably organise metal-containing molecular building blocks in crystalline materials. A novel method for the halogen bond mediated crystal engineering of metal complexes was discovered, which led to the preparation of new materials with potential applications in molecular switching devices and advanced memory storage systems.
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Contino, Catherine Marie. "The electromigration behavior of single crystal copper." Honors in the Major Thesis, University of Central Florida, 2001. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/217.
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This item is only available in print in the UCF Libraries. If this is your Honors Thesis, you can help us make it available online for use by researchers around the world by following the instructions on the distribution consent form at http://library.ucf.edu/Systems/DigitalInitiatives/DigitalCollections/InternetDistributionConsentAgreementForm.pdf You may also contact the project coordinator, Kerri Bottorff, at kerri.bottorff@ucf.edu for more information.Bachelors
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