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Studies of Unusual Packing and of Polymorphism in Two Crystal Systems

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Studies of Unusual Packing and of Polymorphism in Two Crystal Systems University of Kentucky UKnowledge University of Kentucky Doctoral Dissertations Graduate School 2005 STUDIES OF UNUSUAL PACKING AND OF POLYMORPHISM IN TWO CRYSTAL SYSTEMS Xiang Hao University of Kentucky Right click to open a feedback form in a new tab to let us know how this document benefits ou.y Recommended Citation Hao, Xiang, "STUDIES OF UNUSUAL PACKING AND OF POLYMORPHISM IN TWO CRYSTAL SYSTEMS" (2005). University of Kentucky Doctoral Dissertations. 285. https://uknowledge.uky.edu/gradschool_diss/285 This Dissertation is brought to you for free and open access by the Graduate School at UKnowledge. It has been accepted for inclusion in University of Kentucky Doctoral Dissertations by an authorized administrator of UKnowledge. For more information, please contact [email protected]. ABSTRACT OF DISSERTATION Xiang Hao The Graduate School University of Kentucky 2005 STUDIES OF UNUSUAL PACKING AND OF POLYMORPHISM IN TWO CRYSTAL SYSTEMS ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯ ABSTRACT OF DISSERTATION ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯ A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the College of Arts and Sciences at the University of Kentucky By Xiang Hao Lexington, Kentucky Director: Dr. Carolyn P. Brock, Professor of Chemistry Lexington, Kentucky 2005 Copyright © Xiang Hao 2005 ABSTRACT OF DISSERTATION STUDIES OF UNUSUAL PACKING AND OF POLYMORPHISM IN TWO CRYSTAL SYSTEMS Crystal structures of anhydrous pinacol, the hexagonal pinacol, pinacol monohydrate, and pinacol hexahydrate were studied. In all the structures crystal packing is unusual and complicated. The origin of the complexity may be the difficulty in filling space densely and while also satisfying the H-bonding requirements when the molecule has few internal degrees of freedom. Five 15-crown-5 complexes of M(NO3)2 (M = Cu, Zn, Mg, Co, Mn) were synthesized and characterized using X-ray diffraction and differential scanning calorimetry. The system is rich in polymorphs. Nine definite solid-state phases were identified. More phases probably exist in the solid state at temperatures slightly above the room temperature. Most phase transformations in this system take place in single crystals without the loss of crystallinity. The nine phases crystallize in five crystal structures. The crown ether ligands have very similar conformation in all the structures. The asymmetric units in all the structures are complicated and pseudosymmetric, which is the consequence of the presence of the packing problem. The origin of the packing problem that leads to the complicated phase behavior is the odd number of -CH2-O-CH2- units in the crown ether ligand. KEYWORDS: Pinacol, 15-Crown-5, Crystal Packing, H-Bonding, Polymorphism Xiang Hao February 11, 2005 STUDIES OF UNUSUAL PACKING AND OF POLYMORPHISM IN TWO CRYSTAL SYSTEMS By Xiang Hao Dr. Carolyn P. Brock ___________________________________ Director of Dissertation Dr. Mark S. Meier ___________________________________ Director of Graduate Studies March 24, 2005 __________________________________ RULES FOR THE USE OF DISSERTATIONS Unpublished dissertations submitted for the Doctor’s degree and deposited in the University of Kentucky Library are as a rule open for inspection, but are to be used only with due regard to the rights of the authors. Bibliographical references may be noted, but quotations or summaries of parts may be published only with the permission of the author, and with the usual scholarly acknowledgments. Extensive copying or publication of the dissertation in whole or in part also requires the consent of the Dean of the Graduate School of the University of Kentucky. DISSERTATION Xiang Hao The Graduate School University of Kentucky 2005 STUDIES OF UNUSUAL PACKING AND OF POLYMORPHISM IN TWO CRYSTAL SYSTEMS ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯ DISSERTATION ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯ A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the College of Arts and Sciences at the University of Kentucky By Xiang Hao Lexington, Kentucky Director: Dr. Carolyn P. Brock, Professor of Chemistry Lexington, Kentucky 2005 Copyright © Xiang Hao 2005 ACKNOWLEDGMENTS I want to thank my advisor and committee chair, Dr. Carolyn Pratt Brock, who gave me several interesting projects. During my graduate studies at the University of Kentucky, I received many great helps from her. Most importantly, She helped me to understand the projects thoroughly and profoundly. The director of the X-Ray Lab at Department of Chemistry, Dr. Sean Parkin, taught me many knowledge and techniques in crystallography, and helped me to complete my projects in many ways. I also want to thank the other members of my advisory committee, Drs. John P. Selegue, Dong-Sheng Yang, and Marcos A. Oliveira for their expertise, criticism, and comments. I should also thank Dr. Gang Cao, who is willing to be the outside examiner of my final oral examination. I want to thank the former and current Directors of Graduate Studies at Department of Chemistry, Drs. Robert A. Guthrie and Mark S. Meier, who offered me the Teaching Assistant position during my ten-semester residence at the University of Kentucky. iii TABLE OF CONTENTS Acknowledgments.....................................................................................................................iii List of Tables.............................................................................................................................vi List of Figures..........................................................................................................................vii List of Files.............................................................................................................................xiii Chapter One: Introduction Overview........................................................................................................................1 Structures with Z' > 1.....................................................................................................6 Pseudosymmetry............................................................................................................7 Reconstructed Precession Planes...................................................................................8 Separate Wilson Plots...................................................................................................12 Superstructures.............................................................................................................16 Twinning......................................................................................................................23 Polymorphism..............................................................................................................27 Chapter Two: The Unusual Packing of Anhydrous and Hydrated Pinacol Introduction..................................................................................................................31 Experimental................................................................................................................39 Crystal Growth.................................................................................................39 X-Ray Diffraction............................................................................................47 Anhydrous Pinacol.......................................................................................................49 Hexagonal Pinacol........................................................................................................56 Pinacol Monohydrate...................................................................................................64 Pinacol Hexahydrate.....................................................................................................76 Summary and Discussion.............................................................................................86 Anhydrous Phase..............................................................................................88 Hexagonal Phase..............................................................................................88 Monohydrate....................................................................................................89 Hexahydrate.....................................................................................................89 Conclusion....................................................................................................................90 Chapter Three: Polymorphism of 15-Crown-5 Complexes of M(NO3)2, M = Cu, Zn, Mg, Co, Mn Introduction.................................................................................................................91 Experimental..............................................................................................................102 Crystal Growth...............................................................................................102 X-Ray Diffraction..........................................................................................104 Differential Scanning Calorimetry Measurements.........................................106 Structure Determination.............................................................................................106 The Structures of the Cu Compound at 88 K and 294 K...............................106 The Structure of the Cu Compound at 320 K.................................................116 The Structures of the Zn Compound at 90 K and 294 K................................118 The Structure
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