Cryptands definition

The terms crown and cryptand have been universally adopted. A number of other terms have enjoyed less widespread recognition as noted above. Recently, Vogtle and Weber have proposed use of the terms crown ether, cryptand and podand according to the following scheme. Their suggested definitions are as follows ... 

The effect of cation-complexing agents on the barium(II)-assisted basic ethanolysis of phenyl acetate has been looked at.184 Addition of various crown ethers yields ternary complexes of 1 1 1 crown-metal-ethoxide composition and a definite cation activation takes place. Cryptand 222 removes the catalytic activity. 

At this stage, it is helpful to summarise some definitions and to identify the classes of compounds which will be described in the subsequent sections. Definitions are collected in Table 4.21. As can be seen, some definitions overlap. For instance, the distinction between podands and chelating agents is rather thin so that some authors use these terms indifferently. Other differences are also subtle, e.g. between cryptands and sepulchrands. 

Cryptands, p. 334 Hydrogen Bonding, p. 658 Induced Fit, p. 717 The Lock and Key Principle, p. 809 Selectivity Thermodynamic and Kinetic, p. 1225 Self-Assembly Definition and Kinetic and Thermodynamic Considerations, p. 1248... 

Classical Descriptions of Inclusion Compounds, p. 253 Clathrate Hydrates, p. 274 Concepts in Crystal Engineering, p. 319 Crown Ethers, p. 326 Cryptands, p. 334 DNA Nanotechnology, p. 475 Enzyme Mimics, p. 546 The Lock and Key Principle, p. 809 Molecular-level Machines, p. 931 Selectivity Thermodynamic and Kinetic, p. 1225 Self-Assembly Definition and Kinetic and Thermodynamic Considerations, p. 1248 Self-Assembly Terminology, p. 1263 Soft and Smart Materials, p. 1302 Spherands, p. 1344... 

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