Two novel CN[sbnd] turn on fluorescent imaging materials with twin binding groups

Abstract

In this work two novel fluorescent imaging materials for CN with twin binding groups (1 and 2) have been synthesized and fully characterized by standard analytical tools and spectroscopic techniques. The selectivity of 1 and 2 has been explored in aqueous solution, and the resulting turn-on fluorescence response toward CN among different anions was studied. The cyanide ion adduct was characterized using NMR and mass spectroscopy and detection mechanism was further confirmed to be the nucleophilic attack of the indolium group of probe by CN, which induces a turn-on fluorescence change. NMR and mass spectra indicate nucleophilic addition of CN to indolium group is reversible in ionization process. For the practical application of the sensors, 1 could be used for fluorescence-microscopic imaging of CN in biological applications.