Advances in Physical Organic Chemistry

Since the discovery of crown ethers by Pedersen in 1967, several thousands of crown ethers and analogous compounds have been synthesized. Their specific characteristics have been investigated and a variety of applications developed. These developments have led to new fields of chemistry called host-guest chemistry and supramolecular chemistry. This book presents the state-of-the-art of the chemistry of crown ethers and analogous compounds. The first chapter provides an orientation in the new fields of chemistry. Chapter 2 reviews advances in synthetic procedures for crown ethers and analogous compounds including azacrown ethers, thiacrown ethers, functionalized crown ethers, cryptands and others. The focus of chapter 3 is on the concept and synthetic strategies for the molecular design of new crown compounds. Chapters 4-7 are concerned with noteworthy topics in the applications of crown compounds. Chapter 4 deals with the application to ion-selective electrodes and liquid chromatography, both of which are the most important targets in the analytical application of crown compounds. One major application of crown ethers is the design and syntheses of artificial molecules which can catalyze a useful synthetic reaction in an enzyme-mimetic reaction manner, through novel non-covalent complexes. The strategies for enzymatic modelling with crown ethers are covered in chapter 5, while chapter 6 presents the principle of amine-selective colour complexation and its application. In chapter 7 switched-on crown ethers that can respond to environmental stimuli are reviewed. The final chapter is devoted to a wide-ranging discussion of developments in macrocyclic polyamine chemistry. Unlike crown ethers, macrocyclic polyamines, bearing nitrogen donor atoms which belong to a soft base, form complexes with ions of transition metals and heavy metals which are classified as soft acids. Therefore, macrocyclic polyamines are expected to have very versatile applications. Scientists in chemistry, biochemistry, physical organic chemistry, pharmaceutical chemistry and industrial chemistry will find this book a helpful summary and a stimulating contribution to research in this specialized field of crown compounds.

Derived from the "Chemistry of Functional Groups" series, this volume includes key chapters from an earlier volume on crown ethers. Material has been updated and new material included. Topics discussed include the synthesis of crown ethers and analogs and various complexes and selectivity.

Crown Ethers and Cryptands introduces the broad and basic principles of crown ether and cryptand chemistry at the advanced undergraduate, graduate and working professional level. The book provides a brief introduction, outlining the history of the field and goes on to cover syntheses, complexation of cations and molecules, complex structures, applications and recent developments. It aims to acquaint readers with the scope and principles of the field, providing a bibliography of reviews and books as reference to further reading and citations of the original literature.

This reference details the theory and application of cation complexation, including the design and synthesis of various cyclic systems, these materials' use as transport systems, in complexation and selectivity studies by macrocyclic systems, and methodologies for understanding these phenomena. In a

The scientific and practical interest in coronands (crown ethers), cryptands, podands as complexing agents for cations as well as for anions and neutral low molecular species is undeniable 1,2). The chemistry of crown compounds is steadily increasing. About 250 original papers dealing with crown chemistry appeared only in 1980. New molecules· with crown ether properties are constantly synthesized and new applications discov,?red. Owing to lack of space, only a small number of the original publications is men tioned here. Thus, in the literature compilation only some, but relevant works are selected for each chapter. Whenever possible, reference is made to reviews or review-like articles alone by means of which origin,al works can be consulted. The reviews given under ref. 1) are considered to be the most relevant. The formulae presented in the figures should be understood as representative structures outlining a specific field. 2 Classification of Oligo-/Multidentate Neutral Ligands and of their Complexes Today, a distinction is made between the classical ring oligoethers (crown ethers) and monocyclic coronands, oligocyclic spherical cryptands and the acyclic podands with respect to topological aspects 3). This classification and the topology are illustrated in Fig. 1, each figure representing the minimum number of donor atoms and chain segments characteristic of each class of compounds. Multidentate mono cyclic ligands with any type of donor atoms are called coronands ("crown compounds"), while the term crown ether should be reserved for cyclic oligoethers exclusively containing oxygen as donor atom.