New host–guest carriers

Abstract

The design of ligands suitable as ionophores for ion-selective electrodes (i.s.e.) is discussed in terms of the carrier hypothesis, emphasising the balance needed between maximum selectivity and a fast response time. A new type of crown ether is described, which incorporates a triarylmethyl (propeller) substituent, which can be fluxional or rigid. The improved kinetic performance of crowns with rigid propellers suggests further possible exploitation in future designs of ionophore.