Armed crown ether complexes in supramolecular assembly

Recent advances in macrocyclic chemistry and its applications to supramolecular chemistry are described. We first present concept and examples of ''armed crown ethers'', which are characterised by a parent crown ether ring and a functionalised sidearm, Their structural variations extend molecular recognition and add new reactivity to the parent crown ether. As a new synthetic approach, the computer-aided design of Li+ ion-specific armed crown ethers is discussed, The rational design and refined synthesis can offer specific molecular recognition and integrated functions. We also address two interesting approaches developed in the border regions between macrocyclic chemistry and supramolecular chemistry. Armed crown ethers form unique supramolecular assemblies with membranes and biopolymers, These modify the original functionalities of both the armed crown ether and the membrane-biopolymer and further exhibit supramolecular functions, Combinations of armed crown ether chemistry with computer chemistry, membrane chemistry and biopolymer chemistry provide interesting possibilities in creating new functional supramolecular assemblies.