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Dissertations / Theses on the topic 'Polymorphism - Molecular Crystals'

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Published: 4 June 2021

Last updated: 6 September 2023

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1

Nguyen, Thi Yen. "Polymorphism of Organic Molecular Crystals." Doctoral thesis, Humboldt-Universität zu Berlin, 2018. http://dx.doi.org/10.18452/18812.

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Die Kristallisation ist ein wichtiger Teilprozess bei der industriellen Herstellung vieler Materialien und Medikamente. Es ist jedoch ein vielschichtiger, physikalischer Vorgang, der noch nicht vollständig aufgeklärt ist. Der Schwerpunkt dieser Arbeit liegt auf der Kristallisation von organischen, polymorphen Verbindungen aus unterschiedlichen Lösungsmitteln. Die Kristallisationsstudien wurden in einem akustischen Levitator mit Klimakammer, der den Einfluss von Temperatur, Feuchtigkeit und festen Oberflächen steuert, durchgeführt. Verschiedene analytische in-situ-Methoden und deren Koppl

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2

Presti, Davide. "Quantum computational methodologies for the study of molecular crystals." Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066101/document.

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Les cristaux moléculaires présentent des applications importantes dans l'électronique/l'optoélectronique, les systèmes 'host-guest', ou encore pour des systèmes mécaniques photo-actifs.Les propriétés mentionnées ci-dessus sont sensiblement affectées par le polymorphisme, qui influence le comportement de chaque composé présent dans une forme cristalline définie. Ce phénomène est rendu difficile à étudier de par la présence d'interactions de dispersion et/ou liaisons hydrogène.Avec l'objectif de décrire précisément ces interactions, et pour prédire des propriétés électroniques, une approche de m

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3

Day, Graeme Matthew. "Lattice dynamical studies of molecular crystals with application to polymorphism and structure prediction." Thesis, University College London (University of London), 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.404411.

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4

Nguyen, Thi Yen [Verfasser], Klaus [Gutachter] Rademann, Kannan [Gutachter] Balasubramanian, and Ute [Gutachter] Kolb. "Polymorphism of Organic Molecular Crystals / Thi Yen Nguyen ; Gutachter: Klaus Rademann, Kannan Balasubramanian, Ute Kolb." Berlin : Humboldt-Universität zu Berlin, 2018. http://d-nb.info/1185578706/34.

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5

Rosbottom, Ian. "The influence of the intermolecular synthons on the molecular aggregation, polymorphism, crystal growth and morphology of p-aminobenzoic acid crystals from solution." Thesis, University of Leeds, 2015. http://etheses.whiterose.ac.uk/12103/.

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Intermolecular pairwise interactions (synthons) have previously been used to predict physical properties of molecular crystals, such as polymorphism, morphology and mechanical properties. The overall goal of this research was to correlate the synthon strength and nature found in the crystal structures of the α- and β-forms of 4-aminobenzoic acid to experimentally observed data, assessing their applicability for predicting crystallisation conditions that would produce crystals of desirable physical properties. The strength and nature of the synthons found in the α-structure were found to signif

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6

Asmadi, Aldi. "Crystal structure prediction : a molecular modellling study of the solid state behaviour of small organic compounds." Thesis, University of Bradford, 2010. http://hdl.handle.net/10454/4441.

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The knowledge of the packing behaviour of small organic compounds in crystal lattices is of great importance for industries dealing with solid state materials. The properties of materials depend on how the molecules arrange themselves in a crystalline environment. Crystal structure prediction provides a theoretical approach through the application of computational strategies to seek possible crystal packing arrangements (or polymorphs) a compound may adopt. Based on the chemical diagrams, this thesis investigates polymorphism of several small organic compounds. Plausible crystal packings of th

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7

Zelaya, Carlos A. "6,6’-Dimethoxygossypol: Molecular Structure, Crystal Polymorphism, and Solvate Formation." ScholarWorks@UNO, 2011. http://scholarworks.uno.edu/td/136.

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6,6’-Dimethoxygossypol (DMG) is a natural product of the cotton variety Gossypium barbadense and a derivative of gossypol. Gossypol has been shown to form an abundant number of clathrates with a large variety of compounds. One of the primary reasons why gossypol can form clathrates has been because of its ability to from extensive hydrogen bonding networks due to its hydroxyl and aldehyde functional groups. Prior to this work, the only known solvate that DMG formed was with acetic acid. DMG has methoxy groups substituted at two hydroxyl positions, and consequently there is a decrease in its ab

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8

Dichiarante, Elena <1983&gt. "Polymorphs solvates and co-crystals of molecular materials." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amsdottorato.unibo.it/3590/1/Dichiarante_Elena_Tesi.pdf.

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The scope of my research project is to produce and characterize new crystalline forms of organic compounds, focusing the attention on co-crystals and then transferring these notions on APIs to produce co-crystals of potential interest in the pharmaceutical field. In the first part of this work co-crystallization experiments were performed using as building blocks the family of aliphatic dicarboxylic acids HOOC-(CH2)n-COOH, with n= 2-8. This class of compounds has always been an object of study because it is characterized by an interesting phenomenon of alternation of melting points: the acids

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9

Dichiarante, Elena <1983&gt. "Polymorphs solvates and co-crystals of molecular materials." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amsdottorato.unibo.it/3590/.

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The scope of my research project is to produce and characterize new crystalline forms of organic compounds, focusing the attention on co-crystals and then transferring these notions on APIs to produce co-crystals of potential interest in the pharmaceutical field. In the first part of this work co-crystallization experiments were performed using as building blocks the family of aliphatic dicarboxylic acids HOOC-(CH2)n-COOH, with n= 2-8. This class of compounds has always been an object of study because it is characterized by an interesting phenomenon of alternation of melting points: the acids

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10

Svärd, Michael. "Crystal Polymorphism of Substituted Monocyclic Aromatics." Licentiate thesis, KTH, Chemical Engineering and Technology, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-10501.

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11

Sheridan, Andrew Keith. "Kinetics and temperature- and pressure-induced polymorphic phase transformations in molecular crystals." Thesis, King's College London (University of London), 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322597.

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12

BERGANTIN, STEFANO. "Organic semiconductor rubrene: crystal chemistry of derivatives and high-pressure polymorphism." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2014. http://hdl.handle.net/10281/50223.

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Electronic devices based on organic molecules, displaying interesting semiconducting properties, have recently become commercially available after being widely studied for more than twenty years. The focus of the present thesis is the organic semiconductor rubrene, a very promising material in the field of organic electronics, due to its outstanding charge transport properties. The crystal structure of the rubrene derivatives synthesized up to now, to improve the poor solubility of the pristine molecule and its low stability towards oxidation, were analyzed; this was done in order to identify

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13

Sullivan, Rachel. "Molecules, clusters and crystals : the crystallisation of p-aminobenzoic acid from solution." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/molecules-clusters-and-crystals-the-crystallisation-of-paminobenzoic-acid-from-solution(ec826e71-782f-4bb0-9dc2-48cf94a7c941).html.

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Nucleation is a key step in the crystallisation process, where a new crystalline solid phase is created from a supersaturated solution. The applications of crystallisation as a purification and separation technique span many industries, yet still no definitive molecular mechanism for nucleation exists. This PhD is part of a critical mass research project involving researchers from both the Universities of Manchester and Leeds. The aim is to reveal the relationship between structural components of the nucleation transition state, solution phase molecular self-assembly and nano cluster formation

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14

Tuble, Sigrid Chuatoco. "Simulation of polymorphic phase transitions in molecular crystals of resorcinol and D,L-norleucine." Thesis, King's College London (University of London), 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.405835.

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15

Martin, Craig Robert Leslie. "Crystal engineering approaches to controlling the formation of molecular complexes and their polymorphs." Thesis, University of Glasgow, 2012. http://theses.gla.ac.uk/3154/.

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This work aimed to investigate and exploit the hydrogen bonds generated between heterocyclic aromatic compounds, namely benzimidazole and imidazole, and the carboxylic acid group. The flexible but robust hydrogen bonds generated have been used to create molecular complexes, using practical and relevant co-molecules. A systematic approach has been used in the selection of co-molecules on the basis of crystal engineering principles. A library of robust hydrogen bonds and primary structural motifs has been generated, which has been used to explain the solid-state assembly of the collection of mol

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16

Gaines, Etienne. "The nucleation and growth of meta-aminobenzoic acid : a density functional theory and molecular dynamics study." Thesis, Queen Mary, University of London, 2018. http://qmro.qmul.ac.uk/xmlui/handle/123456789/54056.

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Controlling crystal polymorphism, the ability of a molecule to crystallise in different solid forms, is one of the grand, ongoing challenges in materials science. In the pharmaceutical industry particularly, where up to half of the active pharmaceutical active ingredients exhibit polymorphic behaviour, it is of paramount importance to rationalise the impact of experimental conditions, such as the nature of the solvent, on the obtainment of a specific c crystal form. As strategies for the selection of polymorphs is still, by and large, based on a trial-and-error approach, it is necessary to acq

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17

Neumann, M. A., Frank J. J. Leusen, and John Kendrick. "A major advance in crystal structure prediction." Wiley, 2008. http://hdl.handle.net/10454/4740.

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no<br>A crystal ball? A new method for crystal structure prediction combines a tailor-made force field with a density functional theory method incorporating a van der Waals correction for dispersive interactions. In a blind test, the method predicts the correct crystal structure for all four compounds, one of which is a cocrystal. The picture shows the predicted structure of one of the compounds in green and the experimental structure in blue.

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18

Pauchet, Morgan. "Application of the derived crystal packing model to molecular crstals grown in solutions or in gels." Rouen, 2007. http://www.theses.fr/2007ROUES056.

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The Derived Crystal Packing (DCP) model has been partly automated. The docking step can be handled by two computer program. They are tested on two couples of enantiomer / racemic compound to underline their structural similarities. The limits of the model are also discussed. A second part of the study is devoted to the experimentation of the crystallization in gel. This technique is tested with the gel precursor Tetramethoxysilane on several organic compounds. Different methods for the crystallization are described. In addition, a theoretical as well as experimental study is carried out on (±)

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19

Horiguchi, Masahiro. "Development of structurally selective preparation methods of organic crystals by controlling the polymorphism or the arrangement of guest molecules." Kyoto University, 2008. http://hdl.handle.net/2433/136482.

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Kyoto University (京都大学)<br>0048<br>新制・課程博士<br>博士(人間・環境学)<br>甲第13946号<br>人博第419号<br>新制||人||102(附属図書館)<br>19||人博||419(吉田南総合図書館)<br>UT51-2008-C862<br>京都大学大学院人間・環境学・環境学研究科相関環境学専攻<br>(主査)教授田村類, 教授山本行男, 准教授津江広人, 准教授伊藤義勝<br>学位規則第4条第1項該当

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20

Day, G. M., T. G. Cooper, A. Cruz-Cabeza, et al. "Significant progress in predicting the crystal structures of small organic molecules ¿ a report on the fourth blind test." International Union of Crystallography, 2009. http://hdl.handle.net/10454/4748.

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no<br>We report on the organization and outcome of the fourth blind test of crystal structure prediction, an international collaborative project organized to evaluate the present state in computational methods of predicting the crystal structures of small organic molecules. There were 14 research groups which took part, using a variety of methods to generate and rank the most likely crystal structures for four target systems: three single-component crystal structures and a 1:1 cocrystal. Participants were challenged to predict the crystal structures of the four systems, given only their molecu

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21

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.

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This work concerns the interrelationship between thermodynamic, kinetic and structural aspects of crystal polymorphism. It is both experimental and theoretical, and limited with respect to compounds to substituted monocyclic aromatics. Two polymorphs of the compound m-aminobenzoic acid have been experimentally isolated and characterized by ATR-FTIR spectroscopy, X-ray powder diffraction and optical microscopy. In addition, two polymorphs of the compound m-hydroxybenzoic acid have been isolated and characterized by ATR-FTIR spectroscopy, high-temperature XRPD, confocal Raman, hot-stage and scan

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22

Nanna, Saverio <1985&gt. "Optimization of molecular and crystalline forms of drugs, agrochemicals, pesticides in relation to activity, bioavailability, patentability and to the fabrication of polymorphs, solvates, co-crystals with green chemistry methods." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amsdottorato.unibo.it/7050/1/Nanna_Saverio_Tesi.pdf.

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This doctorate was funded by the Regione Emilia Romagna, within a Spinner PhD project coordinated by the University of Parma, and involving the universities of Bologna, Ferrara and Modena. The aim of the project was: - Production of polymorphs, solvates, hydrates and co-crystals of active pharmaceutical ingredients (APIs) and agrochemicals with green chemistry methods; - Optimization of molecular and crystalline forms of APIs and pesticides in relation to activity, bioavailability and patentability. In the last decades, a growing interest in the solid-state properties of drugs in addition

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23

Nanna, Saverio <1985&gt. "Optimization of molecular and crystalline forms of drugs, agrochemicals, pesticides in relation to activity, bioavailability, patentability and to the fabrication of polymorphs, solvates, co-crystals with green chemistry methods." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amsdottorato.unibo.it/7050/.

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This doctorate was funded by the Regione Emilia Romagna, within a Spinner PhD project coordinated by the University of Parma, and involving the universities of Bologna, Ferrara and Modena. The aim of the project was: - Production of polymorphs, solvates, hydrates and co-crystals of active pharmaceutical ingredients (APIs) and agrochemicals with green chemistry methods; - Optimization of molecular and crystalline forms of APIs and pesticides in relation to activity, bioavailability and patentability. In the last decades, a growing interest in the solid-state properties of drugs in addition

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24

Giunchi, Andrea <1993&gt. "Computing the structural and vibrational properties of polymorphic organic molecular crystals through van der Waals corrected density functional theory and the electronic properties of organic thin films through microelectrostatic calculations." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amsdottorato.unibo.it/9829/1/tesi_Andrea_Giunchi_21.pdf.

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The present Thesis reports on the various research projects to which I have contributed during my PhD period, working with several research groups, and whose results have been communicated in a number of scientific publications. The main focus of my research activity was to learn, test, exploit and extend the recently developed vdW-DFT (van der Waals corrected Density Functional Theory) methods for computing the structural, vibrational and electronic properties of ordered molecular crystals from first principles. A secondary, and more recent, research activity has been the analysis with micro

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25

Chen, Chun-Hsing. "Structure, polymorphism, and solid-state reactions of molecular crystals /." 2010.

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26

Ranjan, S., R. Devarapalli, S. Kundu, et al. "Isomorphism: 'Molecular similarity to crystal structure similarity' in multicomponent forms of analgesic drugs tolfenamic and mefenamic acid." 2019. http://hdl.handle.net/10454/17774.

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Yes<br>The non-steroidal anti-inflammatory drugs mefenamic acid (MFA) and tolfenamic acid (TFA) have a close resemblance in their molecular scaffold, whereby a methyl group in MFA is substituted by a chloro group in TFA. The present study demonstrates the isomorphous nature of these compounds in a series of their multicomponent solids. Furthermore, the unique nature of MFA and TFA has been demonstrated while excavating their alternate solid forms in that, by varying the drug (MFA or TFA) to coformer [4-dimethylaminopyridine (DMAP)] stoichiometric ratio, both drugs have produced three di

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27

Nayak, 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. https://etd.iisc.ac.in/handle/2005/1431.

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Three distinct aspects, disorder, polymorphism and co-crystal formation have been addressed in molecular crystals in terms of intra- and intermolecular interactions involving halogens, weak hydrogen bonds and van der Waals interactions. A basic introductory chapter highlights the importance of these three aspects followed by a foreword to the contents. Chapter 1 employs in situ cryo-crystallization techniques to study the crystal and molecular structures of compounds which are liquids at room temperature. Section 1.1 deals with the crystal structure analyses of low melting chloro- and bromo-su

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28

Nayak, 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.

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Three distinct aspects, disorder, polymorphism and co-crystal formation have been addressed in molecular crystals in terms of intra- and intermolecular interactions involving halogens, weak hydrogen bonds and van der Waals interactions. A basic introductory chapter highlights the importance of these three aspects followed by a foreword to the contents. Chapter 1 employs in situ cryo-crystallization techniques to study the crystal and molecular structures of compounds which are liquids at room temperature. Section 1.1 deals with the crystal structure analyses of low melting chloro- and bromo-su

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29

Thomas, Sajesh P. "Phase Behaviour in Crystalline Solids : Exploring the Structure Guiding Factors Via Polymorphism, Phase Transitions and Charge Density Studies." Thesis, 2013. https://etd.iisc.ac.in/handle/2005/3385.

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The thesis entitled "Phase Behaviour in Crystalline Solids: Exploring the Structure Guiding Factors via Polymorphism, Phase Transitions and Charge Density Studies" consists of five chapters divided into two parts. A basic introductory section describes the topics relevant to the work and the methods and techniques utilized. Part A contains two chapters that discuss the structural aspects related to polymorphism, solvatomorphism, conformational preferences and phase transitions exhibited by active pharmaceutical ingredients (APIs). It also discusses the structure-property correlations in API

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Thomas, 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.

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The thesis entitled "Phase Behaviour in Crystalline Solids: Exploring the Structure Guiding Factors via Polymorphism, Phase Transitions and Charge Density Studies" consists of five chapters divided into two parts. A basic introductory section describes the topics relevant to the work and the methods and techniques utilized. Part A contains two chapters that discuss the structural aspects related to polymorphism, solvatomorphism, conformational preferences and phase transitions exhibited by active pharmaceutical ingredients (APIs). It also discusses the structure-property correlations in API c

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31

Dubey, Ritesh. "Crystal Engineering : From Molecule To Crystal Structure Landscape." Thesis, 2015. https://etd.iisc.ac.in/handle/2005/2654.

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Crystal engineering underlies the essence of natural affiliation between the molecule on the one side and the crystal as a supramolecular assembly on the other. Molecular recognition is the fundamental cause for this efficient transformation and if we consider the crystal as a supramolecular entity then it is not at all difficult to conceive crystallization as an outstanding example of molecular recognition. In general, organic compounds often facilitate closed packed crystal structures as described by A. I. Kitaigorodskii in the form of the close packing principle but based on chemical featur

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Dubey, Ritesh. "Crystal Engineering : From Molecule To Crystal Structure Landscape." Thesis, 2015. http://etd.iisc.ernet.in/handle/2005/2654.

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Crystal engineering underlies the essence of natural affiliation between the molecule on the one side and the crystal as a supramolecular assembly on the other. Molecular recognition is the fundamental cause for this efficient transformation and if we consider the crystal as a supramolecular entity then it is not at all difficult to conceive crystallization as an outstanding example of molecular recognition. In general, organic compounds often facilitate closed packed crystal structures as described by A. I. Kitaigorodskii in the form of the close packing principle but based on chemical featur

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Dikundwar, Amol G. "Organic Fluorine in Crystal Engineering : Consequences on Molecular and Supramolecular Organization." Thesis, 2013. https://etd.iisc.ac.in/handle/2005/3352.

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The thesis entitled “Organic fluorine in crystal engineering: Consequences on molecular and supramolecular organization” consists of six chapters. The main theme of the thesis is to address the role of substituted fluorine atoms in altering the geometrical and electronic features in organic molecules and its subsequent consequences on crystal packing. The thesis is divided into three parts. Part I deals with compounds that are liquids under ambient conditions, crystal structures of which have been determined by the technique of in situ cryocrystallography. Part II demonstrates the utilizatio

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Dikundwar, Amol G. "Organic Fluorine in Crystal Engineering : Consequences on Molecular and Supramolecular Organization." Thesis, 2013. http://etd.iisc.ernet.in/2005/3352.

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The thesis entitled “Organic fluorine in crystal engineering: Consequences on molecular and supramolecular organization” consists of six chapters. The main theme of the thesis is to address the role of substituted fluorine atoms in altering the geometrical and electronic features in organic molecules and its subsequent consequences on crystal packing. The thesis is divided into three parts. Part I deals with compounds that are liquids under ambient conditions, crystal structures of which have been determined by the technique of in situ cryocrystallography. Part II demonstrates the utilization

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Kalyani, Suddhapalli Sita. "Study of Solvent Induced Crystal Polymorphism via Molecular Simulations of Crystal Nucleation." Thesis, 2018. https://etd.iisc.ac.in/handle/2005/4734.

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The ability of a compound to exist in different crystal structures is called crystal polymorphism and such crystals of varied spatial arrangement are called polymorphs. The polymorphic forms can differ in their properties such as dissolution rate, solubility, stability etc. Crystal polymorphism is of particular importance in the pharmaceutical industry where the differing properties of the polymorphs of an API (Active Pharmaceutical Ingredient) can affect its bioavailability and consequently the performance of the drug. Since solution crystallization is one of the crucial steps for the s

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Addula, Ravi Kumar Reddy. "Study of solvent induced polymorphism and crystal nucleation from solution." Thesis, 2021. https://etd.iisc.ac.in/handle/2005/5538.

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Crystal polymorphism is the existence of different crystal structures for the same compound. Different polymorphs will have different physical properties, such as solubility and dissolution rate. The early stage of crystallization, called nucleation, plays a vital in determining the structure of the crystal formed. Understanding the molecular mechanism of nucleation enables us to produce specific polymorphs. Unlike nucleation from the melt, nucleation from solution involves many complexities. Two critical issues with simulating nucleation from solution are the slow diffusion of solute m

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Kendrick, John, Frank J. J. Leusen, M. A. Neumann, and de Streek J. van. "Progress in crystal structure prediction." 2011. http://hdl.handle.net/10454/6048.

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The results of the application of a density functional theory method incorporating dispersive corrections in the 2010 crystal structure prediction blind test are reported. The method correctly predicted four out of the six experimental structures. Three of the four correct predictions were found to have the lowest lattice energy of any crystal structure for that molecule. The experimental crystal structures for all six compounds were found during the structure generation phase of the simulations, indicating that the tailor-made force fields used for screening structures were valid and that the

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Davey, R. J., Nicholas Blagden, S. Righini, H. Alison, M. J. Quayle, and S. Fuller. "Crystal Polymorphism as a Probe for Molecular Self-Assembly during Nucleation from solutions: The Case of 2,6 - Dihydroxybenzoic Acid." 2001. http://hdl.handle.net/10454/3944.

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No<br>The relationship between molecular self-assembly processes and nucleation during crystallization from solution is an important issue, both in terms of fundamental physical chemistry and for the control and application of crystallization processes in crystal engineering and materials chemistry. This contribution examines the extent to which the occurrence of crystal polymorphism can be used as an indicator of the nature of molecular aggregation processes in supersaturated solutions. For the specific case of 2,6-dihydroxybenzoic acid a combination of solubility, spectroscopic, crystallizat

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Asmadi, Aldi, John Kendrick, and Frank J. J. Leusen. "Crystal Structure Prediction and Isostructurality of Three Small Molecule." 2010. http://hdl.handle.net/10454/4626.

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No<br>A crystal structure prediction (CSP) study of three small, rigid and structurally related organic compounds (differing only in the position and number of methyl groups) is presented. A tailor-made force field (TMFF; a non-transferable force field specific for each molecule) was constructed with the aid of a dispersion-corrected density functional theory method (the hybrid method). Parameters for all energy terms in each TMFF were fitted to reference data generated by the hybrid method. Each force field was then employed during structure generation. The experimentally observed crystal str

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40

Asiri, A. M., H. G. Heller, D. S. Hughes, et al. "A mechanophysical phase transition provides a dramatic example of colour polymorphism: the tribochromism of a substituted tri(methylene)tetrahydrofuran-2-one." 2014. http://hdl.handle.net/10454/10420.

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Yes<br>Derivatives of fulgides have been shown to have interesting photochromic properties. We have synthesised a number of such derivatives and have found, in some cases, that crystals can be made to change colour on crushing, a phenomenon we have termed "tribochromism". We have studied a number of derivatives by X-ray crystallography, to see if the colour is linked to molecular structure or crystal packing, or both, and our structural results have been supported by calculation of molecular and lattice energies. A number of 5-dicyanomethylene-4-diphenylmethylene-3-disubstitutedmethylene-tetra

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