Komplexchemie von Molekülen mit hydrophilen und lipophilen Hohlräumen und Pseudohohlräumen

Abstract

Molecules forming cavities suited for inclusion of ions or of neutral molecules are described: Open chain oligoethylene glycol ethers with and without rigid donor end groups are shown to complex alkali/alkaline earth metal ions and neutral molecules such as urea and thiourea. The formation of helical ligand conformations in the alkali metal ion complexes has been proven in solution and in the crystal. Novel donor geometries are also found in complexes of the decadentate open chain neutral ligands 9 and 54a. Many armed open chain oligoethylene glycol ethers are able to embrace the cation by formation of a pseudocyclic endo-polarophilic cavity. The properties of synthetic carrier molecules, of drug as well as dye crown ethers are discussed. Complexes between neutral molecules are described: six-armed octopus molecules form crystalline complexes with crown ethers and other organic molecules. The embedding of crown ethers, cryptands, coronates and cryptates into the γ-cyclodextrin cavity allows the formation of cascade complexes. Completely enclosed large rigid and flexible cavities with endopolarophilic and endohydrophobic areas for reception of neutral molecules have been synthesized. Finally, some general uses and possible applications of crown ethers and of other cavity-forming molecules are mentioned.