Photoinduced control of cation binding ability of non-conjugated bichromophoric receptors

Several receptors based on nonconjugated bichromophores displaying phototun able cation binding properties have been designed and studied. Some of thes e systems undergo a reversible photocyclisation to produce a crown ether or a cryptand; the photoswitching induces significant changes on a long time scale (hours to months after illumination) of the complexing ability of the material. Other bitopic receptors display a sudden ann transitory change o f cation concentration only during the singlet excited state lifetime. (C) 1999 Elsevier Science S.A. All rights reserved.