The supramolecular effects on crown ether modified photochromic fulgides based on the authors` work are reviewed from two aspects: (1) supramolecular regulation of photophysical properties; (2) supramolecular effects on chemical reactivity. It is found that the binding of the metal ions through the crown ether moieties could regulate the ground state properties of both fulgides and their colored forms. The absorption spectra are hypsochromically shifted through selective cation binding. The fluorescence spectra are also hypsochromically shifted. Meanwhile, the photochromic reaction of fulgides could also be regulated by the supramolecular effects. The rate of total photoreaction decreases accompanied by the decreasing of the rate of photocyclization through metal ions binding. The decoloring reaction of the colored forms of fulgides (DHNs) is apparently decreased when metal ions were bound, which means the colored form can be stabilized by the selective cation binding. Mechanistic issues concerning the supramolecular effects of crowned fulgides are also discussed.
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