A Practical Guide to Supramolecular Chemistry

Preface ix

Introduction 1

1 Linear components for supramolecular networks 9

1.1 Flexible components 9

1.2 Rigid components from Schiff bases 17

1.3 Flexible tripods 19

1.4 Simple anion hosts 23

1.5 Rigid platforms 30

2 Cyclic synthons 35

2.1 Planar macrocycles from nature 35

2.2 Artificial planar macrocycles – phthalocyanines and other cyclic systems 37

2.3 Serendipitous macrocycles 43

2.4 Adding functionality to the crowns 46

2.5 Azacrowns with sidearms 51

2.6 Water-soluble macrocycles 55

2.7 Catenanes and rotaxanes 60

3 Molecular baskets, chalices and cages 69

3.1 One for beginners 69

3.2 Calixarenes – essential supramolecular synthons 71

3.3 Adding lower rim functionality to the calixarenes 77

3.4 Adding upper rim functionality to the calixarenes 80

3.5 Oxacalix[3]arenes 84

3.6 Oxacalixarene derivatives 91

3.7 Azacalix[3]arenes 99

3.8 Calixarene variations 102

3.9 Molecular cages for cations and anions 107

4 Supramolecular assembly 115

4.1 Detection, measurement, prediction and visualization 115

4.2 X-ray crystallography 115

4.3 Spectroscopic and spectrometric techniques 120

4.4 Binding constant determination 122

4.5 Solid state vs. solution behaviour 127

4.6 Supramolecular chemistry in silico: molecular modelling and associated techniques 127

4.7 Computational approaches 129

4.8 A protocol for supramolecular computational chemistry 141

4.9 Examples of in silico supramolecular chemistry 142

5 Supramolecular phenomena 161

5.1 Clathrates 161

5.2 Stabilization of cation–anion pairs by crown ethers: liquid clathrates 162

5.3 Receptors for the ammonium ion 168

5.4 Purification of fullerenes 170

5.5 Making molecular boxes and capsules 172

5.6 Self-complementary species and self-replication 176

Appendix 1 Integrated undergraduate projects 185

Appendix 2 Reagents and solvents 189

Index 197