Dissertations / Theses on the topic 'Polymorphism (crystallography)'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 45 dissertations / theses for your research on the topic 'Polymorphism (crystallography).'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
Hammond, Robert Paul. "The structural chemistry of the stuffed tridymites A[BPO4] (A=Na; Ag; b=Be, Co, Zn) and A[BCO4] (A=Na, K; B=Al, Fe; C=Si, Ge) /." *McMaster only, 1996.
Find full textDonahue, Michael J. "Polymorph characterization and control /." View online ; access limited to URI, 2007. http://0-digitalcommons.uri.edu.helin.uri.edu/dissertations/AAI3276988.
Full textWells, David F. "Experimental and computational study of the detection and stability of polymorphs using PXRD, DSC and solubility /." View online ; access limited to URI, 2008. http://0-digitalcommons.uri.edu.helin.uri.edu/dissertations/AAI3314449.
Full textChavez, Krystle J. "Crystallization of pseudopolymorphic forms of sodium naproxen in mixed solvent systems." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29759.
Full textCommittee Chair: Rousseau, Ronald; Committee Member: Meredith, Carson; Committee Member: Prausnitz, Mark; Committee Member: Teja, Amyn; Committee Member: Wilkinson, Angus. Part of the SMARTech Electronic Thesis and Dissertation Collection.
Strachan, Clare, and n/a. "Spectroscopic investigation and quantitation of polymorphism and crystallinity of pharmaceutical compounds." University of Otago. School of Pharmacy, 2005. http://adt.otago.ac.nz./public/adt-NZDU20070427.141108.
Full textTian, Fang, and n/a. "Towards a deeper understanding of the polymorphic conversion of carbamazepine in aqueous suspension." University of Otago. School of Pharmacy, 2007. http://adt.otago.ac.nz./public/adt-NZDU20070601.135438.
Full textJohnstone, Russell D. L. "Effect of high pressure on structural oddities." Thesis, University of Edinburgh, 2010. http://hdl.handle.net/1842/3784.
Full textCooper, Brian J. "The investigation of the optical properties of polytypic minerals." Diss., Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/53682.
Full textPh. D.
Zelaya, Carlos A. "6,6’-Dimethoxygossypol: Molecular Structure, Crystal Polymorphism, and Solvate Formation." ScholarWorks@UNO, 2011. http://scholarworks.uno.edu/td/136.
Full textBayés-García, Laura. "Polymorphism and Solid State Miscibility of Triacylglycerols. Application to Food Authentication." Doctoral thesis, Universitat de Barcelona, 2013. http://hdl.handle.net/10803/129313.
Full textLipids, together with proteins and carbohydrates are major nutrients and also employed as lipophilic materials in food, cosmetic and pharmaceutical industries. Alimentary and industrial fats and oils (such as vegetable oils, margarine, chocolate, and confectionery fats) mainly consist of triacylglycerols (TAGs), whose molecules involve different types of fatty acid moieties. TAGs show a complicated crystallization behavior. The physicochemical properties of a TAG molecule are determined by the nature and compositions of the three fatty acid moieties. These properties must be studied not only in their pure systems but also in mixed systems. In particular, studies on binary mixture systems provide valuable information about molecular interactions among different lipid materials. This PhD thesis is based on the study of the in situ polymorphic characterization of the main TAGs of some vegetable and animal fats and oils, some of their mixtures and the use of the polymorphic behavior of edible fats and oils as a tool to determine their authentication. The polymorphic study of the triacylglycerols POP, OPO, POO, POL, SOO, OOO and OOL was in situ characterized by mainly using differential scanning calorimetry (DSC) and synchrotron radiation X-ray diffraction (SR-XRD) with SAXD and WAXD simultaneous measurement. The combined usage of DSC and SR-XRD or laboratory-scale X-ray diffraction enabled us to monitor the occurrence and transformation behavior at different rates of cooling and heating. The results obtained are closely related to actual crystallization processes of edible fats and oils, in which most functional polymorphic forms can be obtained by applying the most efficient thermal treatments. We also determined the phase behavior of binary mixtures of mixed-acid TAGs containing palmitic and oleic fatty acids (i.e. PPO-OPO, PPO-POO and POO-OPO). PPO-OPO system revealed an eutectic behavior, whereas PPO-POO and POO-OPO were molecular compound-forming. Long incubation periods were needed in order to thermodynamically stabilize the binary mixtures, and the results demonstrated that molecular compounds of PPO-POO and POO-OPO were metastable and tended to separate into the pure TAG components. On the other hand, microstructures of spherulites of POP-OPO binary mixtures were analyzed in neat liquid and solution (n-dodecane) systems by using synchrotron radiation microbeam X-ray diffraction (SR-mu-XRD). Due to a molecular compound formation at the 50:50 concentration ratio, 75POP:25OPO and 25POP:75OPO compositions were characterized to study how the microstructures of spherulites of the TAGs mixtures are determined when the molecular compound crystals and POP or OPO component crystals can be formed competitively. Studies of these heterogeneous microstructures in neat liquid and solution are applicable to palm oil fractionation processes by dry and solvent methods. In an attempt to make an approach to complex natural fatty samples, such as olive oil, the polymorphism of multicomponent mixtures (from 3 to 6 TAG components) was analyzed and discussed. Thus, we observed that the polymorphic behavior of an extra virgin olive oil from the Arbequina olive variety was mainly influenced by its main TAGs, whereas apparently minor components did not develop a crucial role. Furthermore, we also used the polymorphic behavior of natural fat and oils (virgin and extra virgin olive oil, and Iberian ham fat) as a tool to determine authenticity (different ham categories depending on the fattening system used) and detection of adulterations (fraudulent additions of hazelnut oil in olive oil). The combined use of DSC and preliminary chemometric calculations permitted determining fraudulent additions of raw hazelnut oil in an extra virgin olive oil (Arbequina) at concentrations below 5%. On the other hand, highly significant differences were detected in the polymorphic behavior of Iberian ham fat from the bellota and cebo categories.
Ngilirabanga, Jean Baptiste. "A supramolecular derivatised study of BIS(Adamantan-1- Aminium) carbonate." University of the Western Cape, 2014. http://hdl.handle.net/11394/4188.
Full textIn this study, new solid supramolecular derivatised forms of bis(adamantine-1-aminium) carbonate (ADTCO3) were prepared. ADTCO3 is a derivative of amantadine used for Parkinson’s disease and has antiviral properties against influenza-A, dengue fever and pharmacological activity towards Parkinson’s disease. The new forms prepared were polymorphic and co-crystal forms of ADTCO3. Polymorphism is a phenomenon where the ability of a substance to exist in two or more crystalline forms occurs when crystallised under different conditions and co-crystallization is the process of formation of multicomponent crystals of a drug substance. New solid forms often display different mechanical, physicochemical and thermal properties that can remarkably influence the bioavailability, hygroscopicity and stability of active pharmaceutical ingredients (APIs). For the formation of polymorphs of ADTCO3, techniques such as dry grinding, solvent-drop grinding, co-precipitation, sublimation and vapour diffusion were applied. For the development of co-crystals and/or complex formation, ADTCO3 was treated in combination with ten selected co-formers viz; benzoic acid, 4-hydroxybenzoic acid, cinnamic acid, 4-hydroxycinnamic acid, succinic acid, tartaric acid, salicylic acid, L-glutamic acid, citric acid monohydrate and L-glutaric acid using similar techniques as applied in the polymorphism study. The first four co-formers were selected for their potential biological activity and the latter six were selected for their generally regarded as safe (GRAS) status. All products were isolated and characterized using different analytical techniques to assess the thermal behaviour of the products by hot stage microscopy (HSM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). FTIR spectroscopy and proton-nuclear magnetic resonance (1HNMR) were used to identify and determine the purity of the parent compounds and the modified forms. X-ray powder diffraction was used to determine the formation of a new phase and single crystal X-ray diffraction was applied at the initial stages to identify ADTCO3 by its unit cell parameters. Furthermore, the Cambridge Structural Database (CSD) and other resources were used to generate information on the molecular structures of all elucidated parent compounds, their polymorphs and reported co-crystals. Four different polymorphic forms of ADTCO3 were identified (viz. ADTCO3 Forms I to IV) and sixteen co-crystals (viz. ADTCO3BA1 to ADTCO3BA5, ADTCO3HBA, ADTCO3CIN, ADTCO3HCIN, ADTCO3SUC, ADTCO3LTTA, ADTCO3SA, ADTCO3CA, ADTCO3GLA, ADTCO3GA) were synthesised. Of the sixteen co-crystals 5 were identified as ADTCO3BA “salt” co-crystal polymorphic forms and 2 as ADTCO3SUC co-crystal polymorphic forms. Two solvated “salt” co-crystal forms were also identified, namely; ADTCO3GLA and ADTCO3LTTA. ADTCO3GLA had a mass loss of 10.3% (n = 2.4) and ADTCO3LTTA had a mass loss of 5.25% (n = 0.86). Finally, the rest of the co-crystals ADTCO3HBA, ADTCO3CIN, ADTCO3HCIN, ADTCO3SA, ADTCO3CA and ADTCO3GA all crystallised as “salt” co-crystals.
Biyikli, Kasim. "Nucleation and growth of crystals of pharmaceuticals on functionalized surfaces." Worcester, Mass. : Worcester Polytechnic Institute, 2006. http://www.wpi.edu/Pubs/ETD/Available/etd-020606-165721/.
Full textBarthe, Stephanie Cecile. "Investigation and modeling of the mechanisms involved in batch cooling crystallization and polymorphism through efficient use of the FBRM." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24752.
Full textCommittee Chair: Dr Rousseau, Ronald W; Committee Co-Chair: Dr Grover Gallivan, Martha; Committee Member: Dr Realff, Matthew; Committee Member: Dr Garmestani, Hamid; Committee Member: Dr Nenes, Athanasios.
Zamani, Younes. "Determination of physical characteristics of food fats." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0007/MQ44324.pdf.
Full textManso, Jalice Y. "Sensor fusion of IR, NIR, and Raman spectroscopic data for polymorph quantitation of an agrochemical compound." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 37 p, 2009. http://proquest.umi.com/pqdweb?did=1694432951&sid=2&Fmt=2&clientId=8331&RQT=309&VName=PQD.
Full textTailleur, Elodie. "Cristaux et polycristaux à transition de spin : relations structure-propriétés multi-échelles, multi-contraintes (T, P)." Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0207/document.
Full textSpin crossover (SCO) compounds with a large hysteresis centered around room temperature (RT) are being constantly pursued although such behavior is very rare and most often noticed in coordination networks. In this context, a new molecular discrete compound, the complex [Fe(PM-PeA)2(NCSe)2], showing a large SCO hysteresis spanning RT has been synthesized in both singlecrystal and powder forms. Then, two research lines emerged. The first one concerns the multi-scales study of the structure-properties relationships, combining single-crystal and powder X-ray diffraction at variable temperature. A particular focus has been made on the microstructural scale, almostunexplored until now. For the first time, the coherent domain sizes and the micro-deformation rate has been quantified for a molecular discrete SCO compound. The second part of this work investigates in detail the pressure-induced SCO. The in situ single-crystal X-ray diffraction studies has been carried out to perform a complete characterization of the crystal structure under pressure. Thereafter, an accurate high-pressure X-ray diffraction measurement on the powder, with a synchrotron radiation,provides a fine track of the pressure-induced SCO and showed a piezo-hysteresis. Experiments coupling pressure and temperature brought crucial information pertaining to variation of bulk moduli withtemperature, the piezo-hysteresis width, the temperature dependence of the pressure transition and pressure-induced SCO abruptness, are provided in detail for the first time
Lee, Seung-Joo. "Structural and functional consequences of disease-related protein variants." Case Western Reserve University School of Graduate Studies / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=case1269545015.
Full textDemiroglu, Ilker. "Effect of Dimensionality and Polymorphism on the properties of ZnO." Doctoral thesis, Universitat de Barcelona, 2014. http://hdl.handle.net/10803/277286.
Full textEl treball de recerca desenvolupat en aquesta tesi es centra en ZnO, un dels semiconductors de tipus II-VI amb un ampli ventall d’aplicacions. En les estructures (ZnO)n suportades, s’observa que la presència del suport afecta l’ordre d’estabilitats dels mateixos però de manera molt més dràstica afecta selectivament les estructures bidimensionals (2D) que, a partir d’una certa grandària, en fase gas són menys estables que les tridimensionals (3D). Els càlculs per a la làmina 2D-ZnO aïllada interaccionant amb l’hidrogen proporcionen una forta evidència per a la formació d’un estat d’enllaços multi-centres de baixa energia quan passa a través de l’anell de Zn3O3 de la làmina 2D-ZnO, permetent així de forma relativament fàcil el transport d’hidrogen a través de la làmina. Quan canviem a models amb illes mes grans, observem reconstruccions estructurals a l’interior i sota l’illa formada per una nova capa incompleta. L’interior de les illes triangulars adopta estructura WZ i esta rodejada per vores amb estructures BCT i cantonades amb estructura T1. S’ha observat que aquests models presenten en un millor acord estructural amb les dades experimentals per el cas de les lamines formades per 2.7 ML que no pas respecte als models que assumeixen una estructura purament grafítica o purament WZ. Hem generat un ampli rang de polimorfs de ZnO basats en lamines hexagonals inspirades en l’enumeració de les seves xarxes subjacents característiques i evaluant l’estabilitat del sòlid “bulk” i les nano-lamines d’aquestes estructures mitjançant calculs ab initio. Hem observat un ampli polimorfisme d’estructures de baixa energia en les nano-lamines amb un ordre d’estabilitat totalment diferent al del sòlid “bulk”. A partir d’aquestes bases generals hem pogut tenir un millor coneixement de les transicions estructurals observades durant el creixement epitaxial i les prediccions d’estabilitat de les nano-lamines en variar-ne el gruix i la pressió exercida. Hem conclòs els nostres resultats explicant que la nanoporositat està inextricablement connectada tant amb la Erel com amb el ΔEgap i hem predit que la nanoporositat pot induir un increment en el band gap de fins a ~1.5 eV relatius a la wurtzita ZnO. Comprovant també la generalitat d’aquest fenomen, pe’l CdS i pel CdSe suggerim que la nanoporositat pot ser emprada com un mètode genèric d’enginyeria de band gap per materials funcionals morfològicament i electrònicament.
Nascimento, Noelle Mariane do [UNESP]. "Polimorfismo nos complexos de trietanolamina dos metais do quarto período." Universidade Estadual Paulista (UNESP), 2012. http://hdl.handle.net/11449/97914.
Full textCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Devido a contradições presentes na literatura quanto à natureza dos complexos dos metais do quarto período da tabela periódica com o ligante tris(2-hidroxietil)amina (trietanolamina) (TEAH3), uma reinvestigação foi feita consistindo na exploração das possibilidades do ligante em formar dímeros ou até polímeros com a propriedade de polimorfismo com sais dos metais de transição Co2+ e Cu2+. Com o metal representativo Zn2+, os compostos não apresentaram a propriedade de se cristalizarem em mais de uma estrutura cristalográfica distinta. Os complexos [MCl(TEAH2)] foram preparados a partir de misturas de soluções de MCl2 e TEAH3 em várias proporções, e os produtos foram caracterizados pela espectroscopia no infravermelho e difratometria de raios-X (em pó e em monocristal). Durante as tentativas de obtenção de monocristais dos complexos [MCl(TEAH2)] (M=Co, Cu, Zn) em álcool isoamílico, observou-se a oxidação inusitada do ligante TEAH2 coordenado, obtendo-se derivados de fórmula geral [M(bic)2] (M=Co, Cu, Zn). A determinação da estrutura molecular e cristalina do monocristal de [Cu(bic)2] obtido foi realizado pelo Prof. Dr. Carlos B. Pinheiro, da Universidade Federal de Minas Gerais (UFMG)
Due to contradictions in the literature as to the nature of the complexes of metals of the fourth period of the periodic table with the ligand tris(2- hydroxyethyl) amine (triethanolamine) (TEAH3), a reinvestigation was made consisting in exploring the possibilities of the ligand to form dimers or even polymers with the property of polymorphism with salts of transition metals Co2+ and Cu2+. With the metal representative Zn2+, the compounds did not show the property to crystallize in more than one different crystal structure. The complexs [MCl(TEAH2)] were prepared from mixtures of solution of MCl2 and TEAH3 in various proportions, and the products were characterized by infrared spectroscopy and X-ray diffraction (powder and single crystal). During attempts to obtain crystals of the complexes [MCl(TEAH2)] (M = Co, Cu, Zn) in isoamyl alcohol, was observed unusual oxidation of TEAH2 coordinated that yield derivatives of formula [M(bic)2] (M = Co, Cu, Zn). The determination of crystal and molecular structure of the single crystal of [Cu(bic)2] obtained was carried out by Professor. Dr. Carlos B. Pinheiro, Universidade Federal de Minas Gerais (UFMG)
Bezzon, Vinicius Danilo Nonato [UNESP]. "Definição de limites para a identificação e quantificação de polimorfos do fármaco finasterida por difração de raios X por policristais." Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/99735.
Full textPolimorfismo é a propriedade de moléculas cristalizarem em mais de uma forma cristalina, o que pode afetar suas propriedades físico-químicas. Esse fenômeno está presente também em fármacos, e a avaliação de matérias-primas para manter o controle do polimorfo presente em comprimidos comercializados tem um papel importante na indústria farmacêutica. A identificação e o controle de formas polimórficas podem ser realizadas utilizando diversas técnicas, dentre as quais: Análise térmica, espectroscopia na região do infra-vermelho, espectroscopia Raman e a difração de raios X por policristais (DRXP). Esta última é uma técnica que permite a caracterização de fases cristalinas, quantificação de amorfo utilizando padrões internos, e por meio do método de Rietveld o refinamento de estrutura cristalina e a quantificação das fases presentes na amostra. No entanto, alguns fatores limitam a identificação e quantificação das fases em misturas em análises por DRXP, e estão relacionados a parâmetros estruturais da amostra como a baixa simetria e grande volume da cela unitária, á características físicas como forma e tamanho dos cristalinos, e resolução dos difratômetros que são definidas pela geometria, fendas, monocromatização do feixe e sistema de detecção
Polymorphism is the property of molecules to crystallize in more than one crystal form, which may affect physicochemical properties. This phenomenon is also present in pharmaceuticals, and evaluation of raw materials to maintain the control of the polymorph present in tables plays an important role in the pharmaceutical industry. The identification and control of polymorphic forms can be performed using various techniques, among which Thermal analysis, infrared spectroscopy, Raman spectroscopy and X-ray powder diffraction. The latter is a technique that allows among things characterization of crystalline phases, quantification of amorphous using internal standards and, by means of Rietveld method, refinement of the crystal structure and quantification of phases present in the sample. However, several factors limit the identification and quantification of the phases in mixtures, and are related to structure parameters of the sample, such as low symmetry and large unit cell volume, the physical characteristics such as crystallite size and shape, and the resolution of diffractometers which are defined by the geometry, slits, beam monochromatization and detection system
Bezzon, Vinicius Danilo Nonato. "Definição de limites para a identificação e quantificação de polimorfos do fármaco finasterida por difração de raios X por policristais /." Araraquara : [s.n.], 2013. http://hdl.handle.net/11449/99735.
Full textCoorientador: Marcelo Ornaghi Orlandi
Banca: Selma Gutierrez Antonio
Banca: Humberto Gomes Ferraz
O Programa de Pós-Graduação em Ciência e Tecnologia de Materiais, PosMat, tem caráter institucional e integra as atividades de pesquisa em materiais de diversos campi da Unesp
Resumo: Polimorfismo é a propriedade de moléculas cristalizarem em mais de uma forma cristalina, o que pode afetar suas propriedades físico-químicas. Esse fenômeno está presente também em fármacos, e a avaliação de matérias-primas para manter o controle do polimorfo presente em comprimidos comercializados tem um papel importante na indústria farmacêutica. A identificação e o controle de formas polimórficas podem ser realizadas utilizando diversas técnicas, dentre as quais: Análise térmica, espectroscopia na região do infra-vermelho, espectroscopia Raman e a difração de raios X por policristais (DRXP). Esta última é uma técnica que permite a caracterização de fases cristalinas, quantificação de amorfo utilizando padrões internos, e por meio do método de Rietveld o refinamento de estrutura cristalina e a quantificação das fases presentes na amostra. No entanto, alguns fatores limitam a identificação e quantificação das fases em misturas em análises por DRXP, e estão relacionados a parâmetros estruturais da amostra como a baixa simetria e grande volume da cela unitária, á características físicas como forma e tamanho dos cristalinos, e resolução dos difratômetros que são definidas pela geometria, fendas, monocromatização do feixe e sistema de detecção
Abstract: Polymorphism is the property of molecules to crystallize in more than one crystal form, which may affect physicochemical properties. This phenomenon is also present in pharmaceuticals, and evaluation of raw materials to maintain the control of the polymorph present in tables plays an important role in the pharmaceutical industry. The identification and control of polymorphic forms can be performed using various techniques, among which Thermal analysis, infrared spectroscopy, Raman spectroscopy and X-ray powder diffraction. The latter is a technique that allows among things characterization of crystalline phases, quantification of amorphous using internal standards and, by means of Rietveld method, refinement of the crystal structure and quantification of phases present in the sample. However, several factors limit the identification and quantification of the phases in mixtures, and are related to structure parameters of the sample, such as low symmetry and large unit cell volume, the physical characteristics such as crystallite size and shape, and the resolution of diffractometers which are defined by the geometry, slits, beam monochromatization and detection system
Mestre
Nascimento, Noelle Mariane do. "Polimorfismo nos complexos de trietanolamina dos metais do quarto período /." Araraquara [s.n.], 2012. http://hdl.handle.net/11449/97914.
Full textAbstract: Due to contradictions in the literature as to the nature of the complexes of metals of the fourth period of the periodic table with the ligand tris(2- hydroxyethyl) amine (triethanolamine) (TEAH3), a reinvestigation was made consisting in exploring the possibilities of the ligand to form dimers or even polymers with the property of polymorphism with salts of transition metals Co2+ and Cu2+. With the metal representative Zn2+, the compounds did not show the property to crystallize in more than one different crystal structure. The complexs [MCl(TEAH2)] were prepared from mixtures of solution of MCl2 and TEAH3 in various proportions, and the products were characterized by infrared spectroscopy and X-ray diffraction (powder and single crystal). During attempts to obtain crystals of the complexes [MCl(TEAH2)] (M = Co, Cu, Zn) in isoamyl alcohol, was observed unusual oxidation of TEAH2 coordinated that yield derivatives of formula [M(bic)2] (M = Co, Cu, Zn). The determination of crystal and molecular structure of the single crystal of [Cu(bic)2] obtained was carried out by Professor. Dr. Carlos B. Pinheiro, Universidade Federal de Minas Gerais (UFMG)
Orientador: Adelino Vieira de Godoy Netto
Coorientador: Stanlei Ivair Klein
Banca: Alexandre de Oliveira Legendre
Banca: Vinicius Caliman
Mestre
Svärd, Michael. "Structural, Kinetic and Thermodynamic Aspects of the Crystal Polymorphism of Substituted Monocyclic Aromatic Compounds." Doctoral thesis, KTH, Teknisk strömningslära, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-33836.
Full textQC 20110527
Lee, Rachael. "Extreme conditions crystallography of polymorphic co-crystals." Thesis, Durham University, 2017. http://etheses.dur.ac.uk/12065/.
Full textBurden, C. H. "Crystallographic studies of ion binding and polymorphism in carbohydrates." Thesis, University of Leeds, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379650.
Full textPortell, Bueso Anna. "Crystal Engineering Studies of Squaric Acid Derivatives." Doctoral thesis, Universitat de Barcelona, 2014. http://hdl.handle.net/10803/285325.
Full textAquesta 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.
Zhang, Qingfei. "Crystallographic studies of the insulin-linked polymorphic region." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/50345.
Full textGuo, Wenbin. "Nouveaux composés à conversion de spin et polymorphisme pour une approche multi-échelle vers les hautes T(LIESST)." Thesis, Bordeaux, 2021. http://www.theses.fr/2021BORD0015.
Full textThe Light-Induced Excited Spin-State Trapping effect (LIESST) appears as one of the most promising and exciting phenomena for applicative devices based on Spin-CrossOver (SCO) complexes. However, the fundamental understanding of the LIESST effect must be yet deeply completed prior to any rational design of any efficient material. For instance, it is still a great challenge to establish the structure-properties relationships corresponding to the LIESST process, though this approach is crucial to discover SCO materials with a high relaxation temperature T(LIESST). The target of this work is therefore to understand how to increase T(LIESST) towards a daily-life temperature range. We choose to reach this goal by increasing the distortion of the metal coordination sphere through two chemistry-based strategies: i) playing at the molecular scale via steric strains produced by halogen-substituted ligands and ii) controlling the molecular stress through polymorphism. Part I displays some fundamental knowledge on SCO and Part II and III are devoted to the synthesis, crystallography and (photo)magnetic studies of new molecular compounds, including polymorphs, of the [Fe(PM-L)2(NCX)2] family. First these new compounds offer a large panel of innovative behaviours, such as, for instance, negative or zero volume expansions at the SCO and the absence of multi-step transition despite independent metal sites within the crystal. This work enlarges significantly the richness of the SCO based perspectives. Second, the deep examination of the relevant parameters to high T(LIESST) as discussed in Part IV brings new features and, overall, definitively proves that all physical scales must be taken into account, leading to a multiscale concept of the LIESST effect
Elder, David. "Physicochemical and crystallographic investigations into the salt formation of two heterocyclic drugs." Thesis, University of Edinburgh, 1992. http://hdl.handle.net/1842/8721.
Full textBofill, Herrera Lidia. "Estudis d'Enginyeria Cristal·lina i Polimorfisme dels compostos nutracèutics Pterostilbé, Ubiquinol i Vitamina D3." Doctoral thesis, Universitat de Barcelona, 2021. http://hdl.handle.net/10803/673939.
Full textHealth has always been one of the main concerns of society, and even more so with the current pandemic situation caused by the virus (SARS-CoV-2). It is well accepted that following a lifestyle with good eating habits directly influences health, as numerous studies prove. Therefore, acquisition of the right nutrients plays a vital role in maintaining normal body function and preventing disease, especially those related to aging (cardiovascular disease, neurodegenerative diseases, type II diabetes, as well as different types of cancer). This is why the demand for functional foods that promote health has received widespread attention, both among health professionals and the general public, thus emerging new concepts such as nutraceuticals. The term nutraceutical, combining two words "nutrient" and "pharmaceutical", was introduced by Stephen DeFelice, an endocrinologist, in 1989. DeFelice defines the nutraceutical compound as "food or part of a food that provides a benefit in the health, including the prevention or treatment of a disease”. Unfortunately, most of these compounds tend to show limiting physicochemical properties, such as low oral bioavailability, low solubility, and in some cases low chemical stability. Pterostilbene, ubiquinol and vitamin D3 are three nutraceutical compounds known for their important biochemical and nutritional functions. Unfortunately, their potential benefits cannot always be fully exploited as they have low oral bioavailability in the case of pterostilbene and chemical unstability in the case of ubiquinol and vitamin D3. The present PhD thesis describes the discovery, synthesis and characterization of new crystalline solid forms, in particular cocrystals with improved physicochemical properties of these three nutraceutical compounds. Cocrystals can show certain advantages over parent compounds in terms of bioavailability and stability and have proven to be alternatives with potential industrial applicability. Different experimental techniques such as grinding, slurry, reaction crystallization and solution crystallization were used for this study. From more than 1,500 screening experiments, 25 new crystalline forms have been discovered, including polymorphs and cocrystals of the three nutraceutical compounds. The crystal structures of 11 out of the new forms have been determined and analyzed in detail. In particular, two of them have been solved by means of direct space methods from powder X-ray diffraction data. In addition, several computational techniques have been used, such as the analysis of intermolecular interactions, the calculation of lattice energies, molecular electrostatic potential surfaces (MEPS), and Hirshfeld surfaces in order to get deeper insight and knowledge at crystallographic and supramolecular level of the 3 active nutraceutical principles.
La salud ha sido siempre una de las principales preocupaciones de la sociedad, y más aún con la situación de pandemia actual producida por el virus (SARS-CoV-2) se es consciente de que llevar un estilo de vida con buenos hábitos alimentarios influye directamente en la salud, existiendo numerosas investigaciones que así lo demuestran. Por lo tanto la adquisición de los nutrientes adecuados juega un papel vital en el mantenimiento de la función normal del cuerpo y la prevención de enfermedades, sobre todo aquellas que están relacionadas con el envejecimiento (enfermedades cardiovasculares, neurodegenerativas, diabetes tipo II, así como varios tipos de cáncer). Es por ello que la demanda de alimentos funcionales que promueven la salud ha recibido una amplia atención, tanto entre profesionales de la salud como entre el público en general, emergiendo así nuevos conceptos como los nutracéuticos. El término nutracéutico combina dos palabras "nutriente" y "farmacéutico" y fue introducido por Stephen DeFelice, médico endocrinólogo, en el año 1989. DeFelice define el compuesto nutracéutico como "aquel alimento o parte de un alimento que proporciona un beneficio en la salud, incluyendo la prevención o el tratamiento de una enfermedad ". Desafortunadamente, la mayoría de estos compuestos suelen presentar propiedades fisicoquímicas limitantes, tales como una baja biodisponibilidad oral, baja solubilidad y en algunos casos baja estabilidad química. El pterostilbeno, el ubiquinol y la vitamina D3 son tres compuestos nutracéuticos conocidos por sus importantes funciones bioquímicas y nutricionales. Lamentablemente no siempre se pueden aprovechar completamente sus potenciales beneficios ya que presentan una baja biodisponibilidad oral en el caso del pterostilbeno e inestabilidad química en el caso del ubiquinol y la vitamina D3. En la presente tesis doctoral se describe el descubrimiento, la síntesis y la caracterización de nuevas formas sólidas cristalinas, en particular cocristales, con mejoras en las propiedades fisicoquímicas de estos tres compuestos nutracéuticos. Los cocristales presentan ventajas respecto a los compuestos de partida en cuanto a biodisponibilidad y estabilidad y han demostrado ser alternativas con potencial aplicabilidad industrial. Para este estudio se utilizaron diferentes técnicas experimentales tales como la molienda, la suspensión, la cristalización y la evaporación lenta. De los más de 1.500 experimentos de cribado, se han obtenido 25 nuevas formas cristalinas, entre ellas polimorfos y cocristales de los tres compuestos nutracéuticos. Las estructuras cristalinas de 11 de las nuevas formas han sido resueltas y analizadas en detalle. En particular, dos de ellas se han resuelto mediante métodos de espacio directo a partir de datos de difracción de rayos X de polvo. Además, se han utilizado diversas técnicas computacionales tales como el análisis de las interacciones intermoleculares, el cálculo de la energía reticular, la construcción de superficies de potencial electrostático molecular (MEP) y superficies de Hirshfeld con el fin de profundizar en el conocimiento a nivel cristalográfico y supramolecular de los 3 principios activos nutracéuticos.
Barbas, Cañero Rafael. "Aplicacions de l’enginyeria cristal·lina al descobriment i estudi de noves formes sòlides de principis actius." Doctoral thesis, Universitat de Barcelona, 2019. http://hdl.handle.net/10803/668062.
Full textThis Thesis describes the design, optimization and implementation of screening methodologies for the research of new solid forms or organic compounds. It is possible to be sure about the most suitable solid form of an API to be developed only when a comprehensive solid-state study has been conducted. The main objective of such a study is to understand the polymorphic landscape, the intermolecular interactions that stabilize the crystal lattice together with the methodologies to prepare the solid forms of interest. In this work, a semi-automatic work methodology for the research of new solid forms adaptable to the pharmaceutical industry needs has been developed starting from a combination between multidisciplinary knowledge in the areas of crystallography and crystal engineering. The application and qualitative validation of the methodologies has been conducted through the study of three active pharmaceutical ingredients. In this sense, 48 new crystal forms (polymorphs, solvates, salts, hybrid salt/cocrystals and cocrystals) have been discovered and 20 crystal structures have been solved. Differential scanning calorimetry, thermogravimetry, powder and single crystal X-ray diffraction, nuclear magnetic ressonance, thermomicroscopy and dynamic vapour sorption have been used to analyse and characterize the new solid forms. The high number of new solid forms discovered in this work has allowed to get a deeper insight in phenomena of great relevance in the field of pharmaceutical solid state, such as the production of new solid forms from solvates, the morphotropism, the formation of hybrid salt/cocrystals, the anion/anion intermolecular interaction and the importance of secondary products for the discovery of new solid forms.
Esta tesis describe el diseño, optimización e implementación de metodologías de screening versátiles para la búsqueda de nuevas formas sólidas de compuestos orgánicos. La certeza de estar desarrollando la forma sólida de un principio activo más adecuada para ser formulada sólo se puede tener cuando se realiza un estudio completo del estado sólido del compuesto. El conocimiento sobre cuáles son las diferentes formas sólidas en las que puede existir un compuesto, de las interacciones intermoleculares que estabilizan sus redes cristalinas, así como la manera de obtenerlas y su caracterización, son los objetivos del estudio de estado sólido del mismo. En este trabajo se ha establecido una metódica de trabajo semi-automática de búsqueda de nuevas formas sólidas que es capaz de adaptarse a las demandas de la industria farmacéutica y que a su vez es modulable en el tiempo, en función del progreso del estudio. El diseño y optimización de las metodologías de screening se han desarrollado a partir de la combinación de los conocimientos multidisciplinares adquiridos de diferentes áreas como son los estudios de estado sólido, la cristalografía y la ingeniería cristalina. La aplicación y verificación cualitativa de las metodologías se ha realizado a través del estudio de tres casos prácticos con compuestos de interés farmacéutico. Se han descubierto 48 nuevas fases cristalinas: polimorfos, solvatos, sales, híbridos y cocristales de los tres principios activos estudiados y se han resuelto y analizado 20 estructuras cristalinas. Para el análisis y caracterización de los diferentes sólidos cristalinos descubiertos se han utilizado diferentes técnicas experimentales como la calorimetría diferencial de barrido, termogravimetría, espectroscopía de resonancia magnética nuclear, difracción de rayos X de polvo y de monocristal, sorción dinámica de vapor y termomicroscopía. El gran número de formas sólidas descubiertas de los tres principios activos ha permitido profundizar en el estudio de diversos fenómenos de gran relevancia dentro del campo del estado sólido farmacéutico: la generación de formas sólidas a partir de la desolvatación de solvatos que enmascaran su existencia, el morfotropismo, la formación de compuestos híbridos sal- cocristal, las interacciones intermoleculares anión-anión o la constatación de que la aparición de productos secundarios condicionan la búsqueda de nuevas formas sólidas.
Dekhil, Myriam. "RMN cristallographique : mesure de distances internucléaires sur des échantillons de poudre par RMN du solide." Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4734.
Full textMeasurment of dipolar coupling provides 3D structural information of powder samples. However, in practice, the high density of spins in organic compounds prevents the measurements of long-range dipolar couplings in solid-state NMR by the so-called dipolar truncation effect. The study of rare spins on natural abundance allows to overcome this problem. In fact, with a natural abundance of 1.1 %, the probability for three 13C to be coupled is negligible. We developed a methodology based either on the dipolar recoupling NMR pulse sequence POST-C7 or on the dramatic increase in sensitivity provided by dynamic nuclear polarization. We demonstrated that its methodology provides a measure of 13C-13C dipolar couplings in natural abundance powder samples and that the so-obtained distance information is sensitive to both molecular conformation and crystal packing of powder samples. Moreover, we show that the recoupling pulse sequence R20_9_2 is more robust to strong chemical shift anisotropy and also to strong 1H-13C heteronuclear dipolar couplings than POST-C7. The second challenge involves 13C signal assignment for natural abundance. In fact, there are only a few examples of 13C-13C correlation spectra obtained for natural abundance samples. Here, we show that 13C-13C correlation spectra sequence based on the reintroduction of 13C−13C dipolar couplings can be obtained with standard MAS probe and within few days using R20_9_2 pulse sequence. Contrary to pulse sequences based on 13C-13C J coupling, our pulse sequence requires shorter DQ excitation time and hence, is more suitable for samples having short T2 relaxation times such as amorphous solids
Mnguni, Malitsatsi Jesse. "Polymorphism in pharmaceutical co-crystals." Thesis, 2017. http://hdl.handle.net/10539/22734.
Full textPolymorphism is not only limited to single component systems. Co-crystals have exhibited polymorphism and various polymorphic co-crystals have been reported. Polymorphism in co-crystals presents an expansion of the optimization space around a pharmaceutical compound and also offers the opportunity to develop novel patentable material. Polymorphism of pharmaceutical co-crystals was investigated by means of an exhaustive data mining survey and the formation of polymorphic co-crystals. The search was performed using the Cambridge Structural Database (CSD). The search aimed to find and tally neutral pharmaceutical co-crystals which are polymorphic. The survey of the CSD showed that 14% of the pharmaceutical co-crystals were polymorphic. The co-crystal of theophylline and 3,4-dihydroxybenzoic acid was found to be polymorphic and the novel polymorph was synthesized and characterized. The co-crystals were characterized by x-ray crystallographic techniques and Differential Scanning Calorimetry. The single crystals of carbamazepine and cinnamic acid was grown and characterized by SCXRD for the first time. The single crystal data was able to show that the hydrogen bonding packing that was modelled in the literature is incorrect.
MT2017
Hean, Duane. "Polymorphism and structural studies of isoniazid derivatives." Thesis, 2015. http://hdl.handle.net/10539/18526.
Full textCrystal polymorphism is the capacity of a solid crystalline form to exist in more than one structural arrangement. In the pharmaceutical setting investigations into the polymorphic forms of potential drugs are of vital importance since different crystalline forms can affect bioavailability, mechanical, thermal, and chemical properties. One such example is isonicotinic acid-(1-phenylethylidene) hydrazide (IPH), a derivative of the popular drug isoniazid (used as first line treatment against Mycobacterium tuberculosis) was found to crystallise in six different polymorphic forms. Each crystal structure was determined using X-ray diffraction techniques and including the thermal phase relationships of the polymorphic compound were delineated. In addition to polymorph elucidation, isonicotinic acid-(1-phenylethylidene) hydrazide was modified with –OH and –NH2 at various aromatic positions, creating geometric pyridyl isomers. In-depth studies of these pyridyl isomers revealed a diverse range of supramolecular aggregates. Preliminary thermal screening suggests that only a small selection of these pyridyl isomers present potential polymorphic activity for further study.
Rademeyer, Melanie. "Polymorphism in long-chain n-alkylammonium halides." Thesis, 2008. http://hdl.handle.net/10210/414.
Full textProf. G.J. Kruger
Ghezelbash, Hossein-Ali. "Topics in colloidal nanocrystals: synthesis and characterization, polymorphism, and self-assembly." Thesis, 2006. http://hdl.handle.net/2152/2485.
Full textChen, Chun-Hsing. "Structure, polymorphism, and solid-state reactions of molecular crystals /." 2010.
Find full textThomas, Sajesh P. "Phase Behaviour in Crystalline Solids : Exploring the Structure Guiding Factors Via Polymorphism, Phase Transitions and Charge Density Studies." Thesis, 2013. http://etd.iisc.ernet.in/2005/3385.
Full textNayak, Susanta Kumar. "Disorder, Polymorphism And Co-Crystal Formation In Molecular Crystals : An In-Depth Study In Terms Of Weak Intra- And Intermolecular Interactions." Thesis, 2010. http://etd.iisc.ernet.in/handle/2005/1431.
Full textKaur, Ramanpreet. "Structure-Function Control in Organic Co-Crystals/Salts Via Studies on Polymorphism, Phase Transitions and Stoichiometric Variants." Thesis, 2015. http://etd.iisc.ernet.in/2005/3729.
Full textDubey, Ritesh. "Crystal Engineering : From Molecule To Crystal Structure Landscape." Thesis, 2015. http://etd.iisc.ernet.in/handle/2005/2654.
Full textDikundwar, Amol G. "Organic Fluorine in Crystal Engineering : Consequences on Molecular and Supramolecular Organization." Thesis, 2013. http://etd.iisc.ernet.in/2005/3352.
Full textSaouane, Sofiane. "Extending the Search Space for Novel Physical Forms of Pharmaceuticals and Biomolecules using High-Pressure Techniques." Doctoral thesis, 2015. http://hdl.handle.net/11858/00-1735-0000-0028-878A-D.
Full textMukherjee, Arijit. "Building Upon Supramolecular Synthons : Some Aspects of Crystal Engineering." Thesis, 2013. http://etd.iisc.ernet.in/2005/3455.
Full textVasudev, Prema G. "X-Ray Crystallographic Studies Of Designed Peptides : Characterization Of Novel Secondary Structures Of Peptides Containing Conformationally Constrained α-, β- And γ-Amino Acids And Polymorphic Peptide Helices." Thesis, 2009. http://hdl.handle.net/2005/922.
Full text