Tetrahydro[5]helicene-based dye with remarkable and reversible acid/base stimulated fluorescence switching properties in solution and solid state

A new organic imide dye based on tetrahydro[5]helicene skeleton was synthesized, and its helical structural feature was confirmed by the crystal structure. It was found that the dye exhibited remarkable and reversible acid/base stimulated fluorescence switching properties in both solution and solid state, in which the dye was changed from D-A type to A-A type in the presence of TFA, and returned to its original form upon the addition of TEA. This switchable behavior was also evidenced by the H-1 NMR experiments and theoretical calculations. (C) 2015 Elsevier Ltd. All rights reserved.