A highly specific ca²⁺-ion sensor: signaling by exciton interaction in a rigid-flexible-rigid bichromophoric "H" foldamer

Abstract

A bichromophoric "H"-foldamer (rigid-flexible-rigid) demonstrates a cation-steered exciton interaction (see figure; the interaction is denoted by the double-headed arrow) and thereby allows the selective signaling of Ca²⁺-ion binding among Na⁺, K⁺, and Mg²⁺ ions. The binding can be observed with the naked eye, as well as by absorption, emission, and ¹H NMR spectral changes. An analogous monochromophore (flexible-rigid-flexible) failed to signal any of the binding events.