An aggregation-induced emissive chromophore as a ratiometric fluorescent sensor for cyanide in aqueous media

A para-terphenyl derivative containing a lateral diphenylamino group and two terminal dicyanovinyl groups has been designed and synthesized. This compound displays aggregation-induced emission characteristics and thus shows intense intramolecular charge transfer fluorescence even in the condensed state, including in the aggregates formed in an aqueous solvent system consisting of greater than 99% water and in the solid state. The addition of cyanide to its aggregates in aqueous media induces a large blue shift in fluorescence, enabling ratiometric fluorescence sensing of cyanide anions. In addition, its prompt fluorescence responses to cyanide anions were also observed even in the solid state.