Cooperativity and the Chelate, Macrocyclic and Cryptate Effects

Abstract The interrelationships between cooperativity and the chelate, macrocyclic, and cryptate effects are described in this chapter. The chapter begins by defining and providing a brief historical background of these four closely related effects as they pertain to both transition metal coordination chemistry and supramolecular chemistry. The second section provides an overview of bonding for supramolecular chemistry with a comparison illustrating similarities with and differences from transition metal coordination. Sections 3 and 4 describe the chemistry of the chelate, macrocyclic, and cryptate effects and the important role that cooperativity plays in each for transition metals coordination and supramolecular chemistry, respectively. Thermodynamic aspects and structural foundations for the increasing stability of complexes as they evolve from chelates through cryptates are also described. Section 4 on supramolecular chemistry is further divided into sections on the chemistry of cations, followed by anions. A short conclusion is provided at the end of the chapter. Throughout the chapter, examples are provided that illustrate the manner in which these important chemical effects are manifested.