Cation-binding properties of new armed macrocyclic host molecules and their applications to phase-transfer reactions and cation membrane transport

Abstract

A new series of armed macrocyclic host molecules was prepared; the macrocycles were characterized by parent macrocyclic ligands and cation-ligating donor arms. Their cation-binding properties were significantly controlled by co-ordination characteristics of their parent macro-ring and donor side-arms, and chemical modifications of their basic structures provided interesting chemical functions. For example, a furan-bearing double armed crown ether showed high catalytic activity in some phase-transfer reactions; a multi-armed cyclam containing furan-oxygen atoms discriminated NH₄⁺ion from K⁺ and other related cations effectively. Such chemical functions of these armed macrocycles were not attained with common crown ethers and cryptands. Hence, further variations of ligand structures may lead to a new series of host molecules showing unique and important chemical functions.