Electrostatic Control of Intramolecular Electron Transfer in Calix[4]diquinones Bearing an Appended Chromophore

Binding of K ⁺ or Ba ²⁺ ions attenuates intramolecular electron transfer between a chromophore and an electron-affinic macrocyclic receptor (see schematic representation), and simultaneously amplifies luminescence. In the complexed state, photons absorbed by the dicationic chromophore are emitted as luminescence, whereas illumination of the uncomplexed superstructure causes rapid reduction of the receptor.