Reversible, controllable white-light emission of dye systems by dynamic covalent furan moiety exchange

Abstract

New exo-Diels–Alder adduct dyes were synthesized. Pure exo and endo dye isomers were isolated and prepared. Two high-quality, blue-light emitting crystals were obtained. X-ray single crystal diffraction reveals the precise structure of the exo isomer, and longer Diels–Alder bonds (1.59 Å) than common C–C bonds (1.54 Å). The adduct dye displays high intramolecular energy transfer efficiency from the pyrene donor to the dansyl acceptor, where blue-violet donor emission is prohibited. By dynamic furan moiety exchange, the donor fluorescence restores, which combines with complementary green-yellow acceptor fluorescence to give white-light emission of the dye systems. White and green-light emitting dye systems could be reversibly, controllably, and mutually transformed.