Crystal engineering : a textbook

## Crystal Engineering Crystal engineering is the understanding of intermolecular interactions in the context of crystal packing and the utilization of such understanding in the design of new solids with desired physical and chemical properties. It is a subject of great scope and application that has developed by a coming together of thought streams from many other subjects. During the last 30 years, it has attracted the attention and interest of a varied group of scientists, notably crystallographers and chemists. The purpose of this text book is to provide a brief, basic introduction to this fascinating and important subject that has moved from the fringes into the mainstream of chemistry. Crystal engineering is concerned primarily with molecular solids. We need to distinguish these substances from extended solids such as rocksalt, diamond and metal oxides. The molecular concept is fundamental to chemistry. Our awareness of the molecule as an entity in itself originates from the time when organic chemistry became a separate subject. In 1828, Friedrich Wöhler synthesized urea from ammonium cyanate (Chapter 3) in an experiment that was counter intuitive for that time. Gradually, there arose the idea of the molecule, and during much of the 19th century this molecular paradigm became reinforced through the efforts of the legendary German chemists of that time. The molecule is a group of atoms held together with interactions that are so strong that it remains relatively stable under many variations in temperature and pressure. Molecules do not normally revert spontaneously to atoms. A molecule of, say phenol is the form of that chemical substance that exists in the gas, liquid and solid phases of the compound. The thermal energy that is needed to convert solid phenol to a liquid and eventually to a gas is much smaller than the energy that is required to break the strong interactions between the C, H and O atoms that make up the The molecule is paramount in chemistry. But rather than talk about molecules in themselves, we discuss in this book assemblies of molecules and why molecules associate in specific ways. A crystal is a very precise and specific type of molecular assembly. Crystal engineering teaches us how to bring molecules together exactly as we want. Contents 6 Preface 10 Acknowledgements 12 Copyright Permissions 14 1 Crystal Engineering 16 1.1 X-ray Crystallography 18 1.2 Organic Solid State Chemistry 20 1.3 The Crystal as a Supramolecular Entity 22 1.4 Modern Crystal Engineering 25 1.4.1 Horizontal and Vertical Divisions of Chemistry 25 1.4.2 Organic Crystal Engineering 26 1.4.3 Metal-Organic Crystal Engineering 30 1.4.4 Properties of Crystals 31 1.5 Summary 32 1.6 Further Reading 36 1.7 Problems 37 2 Intermolecular Interactions 40 2.1 General Properties 41 2.2 van der Waals Interactions 43 2.2.1 Close Packing 44 2.3 Hydrogen Bonds 47 2.3.1 Weak Hydrogen Bonds 51 2.3.2 Hierarchies of Hydrogen Bonds 52 2.4 Halogen Bonds 53 2.5 Other Interactions 55 2.6 Methods of Study of Interactions 56 2.6.1 Crystallography 56 2.6.2 Crystallographic Databases 58 2.6.2.1 Graph Sets 61 2.6.3 Spectroscopy 61 2.6.4 Computational Methods 62 2.6.4.1 Crystal Structure Prediction 63 2.7 Analysis of Typical Crystal Structures 64 2.8 Summary 66 2.9 Further Reading 67 2.10 Problems 68 3 Crystal Design Strategies 70 3.1 Synthesis in Chemistry 70 3.2 Supramolecular Chemistry 72 3.3 The Synthon in Crystal Engineering 74 3.3.1 Some Representative Synthons 75 3.3.2 The Carboxyl Dimer Synthon 77 3.3.3 Structural Insulation in Crystal Engineering 80 3.3.4 Discovery of New Synthons 82 3.3.5 Two-dimensional Patterns 84 3.3.6 Higher Dimensional Control 85 3.3.7 Coordination Polymers as Networks 86 3.3.8 Useful Synthons 87 3.4 Summary 89 3.5 Further Reading 89 3.6 Problems 90 4 Crystallization and Crystal Growth 92 4.1 Crystallization of Organic Solids 93 4.1.1 Solution Crystallization 93 4.1.1.1 Antisolvent Crystallization 93 4.1.2 Melt Crystallization 94 4.1.3 Sublimation 94 4.1.4 Hydrothermal and Solvothermal Crystallization 95 4.1.5 Crystallization from a Solid Phase 96 4.1.5.1 Single Crystal to Single Crystal (SCSC) Transformations 96 4.1.5.2 Mechanochemistry 97 4.1.6 Crystallization of Chiral Solids 98 4.2 Nucleation 99 4.2.1 Nucleation as Distinct from Crystal Growth 99 4.3 Thermodynamics and Kinetics of Crystallization 101 4.4 Crystal Growth 102 4.4.1 The Terrace-Ledge-Kink Model of Crystal Growth 103 4.4.2 Two-dimensional Nucleation versus Growth at Dislocations 104 4.4.3 Ostwald Ripening 105 4.5 Crystal Morphology and Habit 105 4.5.1 Crystal Morphology and Crystal Symmetry 106 4.6 Crystal Morphology Engineering 106 4.6.1 Tailor-made Inhibitors 107 4.7 Why is it that all Compounds don’t seem to Crystallize Equally Well or Equally Quickly? 108 4.8 Summary 109 4.9 Further Reading 110 4.10 Problems 111 5 Polymorphism 114 5.1 What is Polymorphism? 114 5.1.1 Polymorphism and the Pharmaceutical Industry 115 5.1.2 Some Simple Definitions 117 5.2 Occurrence of Polymorphism 120 5.2.1 Polymorphism and Intermolecular Interactions 121 5.3 Thermodynamics of Polymorphism 123 5.3.1 Free Energy Diagrams and Stability of Polymorphs 124 5.3.2 Monotropes and Enantiotropes 125 5.3.2.1 Burger-Ramberger Rules 126 5.3.2.2 Distinguishing between Enantiotropes and Monotropes 127 5.4 Thermodynamics versus Kinetics and the Formation of Polymorphs 128 5.5 Methods of Polymorph Characterization 129 5.5.1 Hot Stage Microscopy 129 5.5.2 X-ray Diffraction 129 5.5.3 Thermal Analysis 130 5.6 Properties of Polymorphs 131 5.6.1 Color 131 5.6.2 Mechanical Properties 132 5.6.3 Chemical Reactivity 133 5.6.3.1 Polymorphism in Energetic Materials 134 5.6.3.2 Polymorphism and Reactivity of Drugs 134 5.7 Case Studies from the Pharmaceutical Industry 135 5.7.1 Ranitidine 135 5.7.2 Ritonavir 136 5.7.3 Aspirin 138 5.7.4 Omeprazole 140 5.8 Polymorphism Today 141 5.9 Summary 142 5.10 Further Reading 143 5.11 Problems 144 6 Multi-component Crystals 146 6.1 General Classification and Nomenclature 146 6.2 Solid Solutions 148 6.3 Host-Guest Compounds 149 6.3.1 Design of Hosts 150 6.4 Solvates and Hydrates 155 6.5 Donor-Acceptor Complexes 156 6.6 Co-crystals 158 6.6.1 Hydrogen Bonded Co-crystals 159 6.6.2 Pharmaceutical Co-crystals 162 6.6.2.1 Design of Pharmaceutical Co-crystals 162 6.6.2.2 Properties of Pharmaceutical Co-crystals 163 6.6.2.3 Co-crystals and Salts 164 6.7 Summary 165 6.8 Further Reading 165 6.9 Problems 166 7 Coordination Polymers 170 7.1 What are Coordination Polymers? 170 7.2 Classification Schemes 173 7.3 Crystal Design Strategies 174 7.4 Network Topologies 174 7.4.1 Net Symbols and Nomenclature 175 7.4.2 Topologies of Three-dimensional Structures 176 7.4.2.1 Diamond Topology 176 7.4.2.2 NaCl Topology 177 7.4.2.3 NbO and CdSO4 Topologies 178 7.4.2.4 PtS and Related Topologies 179 7.5 Supramolecular Isomerism 180 7.6 Interpenetration 183 7.7 Porous Coordination Polymers 185 7.7.1 Pore Size 186 7.7.2 Gas Sorption and Storage 186 7.8 Properties and Applications 189 7.8.1 Magnetism, Magnetic Ordering and Spin Crossover 189 7.8.2 Luminescence and Sensing 192 7.8.3 Nonlinear Optical Properties 193 7.8.4 Proton Conductivity 194 7.8.5 Ferroelectricity 194 7.8.6 Birefringence 195 7.8.7 Negative Thermal Expansion 196 7.8.8 Processability 196 7.8.9 Chemical Reactivity 198 7.8.9.1 Structural Transformations on Heating 198 7.8.9.2 [2+2] Cycloaddition Reactions 199 7.8.9.3 Structural Transformations due to Loss of Solvents 199 7.8.9.4 Reactivity of Supramolecular Isomers 200 7.9 Building Approach: Influence of Experimental Conditions 201 7.10 Summary 202 7.11 Further Reading 203 7.12 Problems 204 Glossary 208 Some Data on Crystallographic Space Groups 220 List of Useful Web Sites 222 Some Useful Educational References in Crystal Engineering 226 Index 228 Content: Intro Contents Preface Acknowledgements Copyright Permissions 1 Crystal Engineering 1.1 X-ray Crystallography 1.2 Organic Solid State Chemistry 1.3 The Crystal as a Supramolecular Entity 1.4 Modern Crystal Engineering 1.4.1 Horizontal and Vertical Divisions of Chemistry 1.4.2 Organic Crystal Engineering 1.4.3 Metal-Organic Crystal Engineering 1.4.4 Properties of Crystals 1.5 Summary 1.6 Further Reading 1.7 Problems 2 Intermolecular Interactions 2.1 General Properties 2.2 van der Waals Interactions 2.2.1 Close Packing 2.3 Hydrogen Bonds 2.3.1 Weak Hydrogen Bonds. 2.3.2 Hierarchies of Hydrogen Bonds2.4 Halogen Bonds 2.5 Other Interactions 2.6 Methods of Study of Interactions 2.6.1 Crystallography 2.6.2 Crystallographic Databases 2.6.2.1 Graph Sets 2.6.3 Spectroscopy 2.6.4 Computational Methods 2.6.4.1 Crystal Structure Prediction 2.7 Analysis of Typical Crystal Structures 2.8 Summary 2.9 Further Reading 2.10 Problems 3 Crystal Design Strategies 3.1 Synthesis in Chemistry 3.2 Supramolecular Chemistry 3.3 The Synthon in Crystal Engineering 3.3.1 Some Representative Synthons 3.3.2 The Carboxyl Dimer Synthon. 3.3.3 Structural Insulation in Crystal Engineering3.3.4 Discovery of New Synthons 3.3.5 Two-dimensional Patterns 3.3.6 Higher Dimensional Control 3.3.7 Coordination Polymers as Networks 3.3.8 Useful Synthons 3.4 Summary 3.5 Further Reading 3.6 Problems 4 Crystallization and Crystal Growth 4.1 Crystallization of Organic Solids 4.1.1 Solution Crystallization 4.1.1.1 Antisolvent Crystallization 4.1.2 Melt Crystallization 4.1.3 Sublimation 4.1.4 Hydrothermal and Solvothermal Crystallization 4.1.5 Crystallization from a Solid Phase. 4.1.5.1 Single Crystal to Single Crystal (SCSC) Transformations4.1.5.2 Mechanochemistry 4.1.6 Crystallization of Chiral Solids 4.2 Nucleation 4.2.1 Nucleation as Distinct from Crystal Growth 4.3 Thermodynamics and Kinetics of Crystallization 4.4 Crystal Growth 4.4.1 The Terrace-Ledge-Kink Model of Crystal Growth 4.4.2 Two-dimensional Nucleation versus Growth at Dislocations 4.4.3 Ostwald Ripening 4.5 Crystal Morphology and Habit 4.5.1 Crystal Morphology and Crystal Symmetry 4.6 Crystal Morphology Engineering 4.6.1 Tailor-made Inhibitors. 4.7 Why is it that all Compounds donâ#x80 #x99 t seem to Crystallize Equally Well or Equally Quickly?4.8 Summary 4.9 Further Reading 4.10 Problems 5 Polymorphism 5.1 What is Polymorphism? 5.1.1 Polymorphism and the Pharmaceutical Industry 5.1.2 Some Simple Definitions 5.2 Occurrence of Polymorphism 5.2.1 Polymorphism and Intermolecular Interactions 5.3 Thermodynamics of Polymorphism 5.3.1 Free Energy Diagrams and Stability of Polymorphs 5.3.2 Monotropes and Enantiotropes 5.3.2.1 Burger-Ramberger Rules 5.3.2.2 Distinguishing between Enantiotropes and Monotropes 5.4 Thermodynamics versus Kinetics and the Formation of Polymorphs. This book is important because it is the first textbook in an area that has become very popular in recent times. There are around 250 research groups in crystal engineering worldwide today. The subject has been researched for around 40 years but there is still no textbook at the level of senior undergraduates and beginning PhD students. This book is expected to fill this gap.The writing style is simple, with an adequate number of exercises and problems, and the diagrams are easy to understand. This book consists major areas of the subject, including organic crystals and co-ordination polymers, and can easily form the basis of a 30 to 40 lecture course for senior undergraduates. The writing style is simple, with an adequate number of exercises and problems, and the diagrams are easy to understand. This book consists major areas of the subject, including organic crystals and co-ordination polymers, and can easily form the basis of a 30 to 40 lecture course for senior undergraduates."--Pub. desc Deals with the subject of crystal engineering. This book consists major areas of the subject, including organic crystals and co-ordination polymers. Gautam R. Desiraju, Jagadese J Vittal, Arunachalam Ramanan. Includes Bibliographical References And Index.