Double armed crown ethers and armed macrocycles as a new series of metal-selective reagents: A review

Abstract

Various double armed crown ethers and related macrocycles are presented as metal-selective reagents characterized by macrocyclic ligands and metal-ligating sidearms. They exhibit unique metal binding and recognition functions via macroring-sidearm cooperative action. Since they form three dimensional complexes suitable for metal-sensing and separation, we can develop a new series of metal-selective reagents via armed macrocycle strategy. Polymerization and immobilization of the armed macrocycles further enhance the usefulness in analytical science. This review focuses primarily on the molecular design, host—guest chemistry, and analytical applications of the armed macrocycles, and clearly indicates that these macrocycles provide new options in designing a metal-selective reagent.