Design of fluorescence turn-on sensors with novel response mechanism based on C[dbnd]N isomerization

Abstract

A series of new type naphthalimide-based fluorescent molecules linking aniline-like groups via a coupling chain with –CN– structure were developed as novel fluorescence chemosensors with high sensitivity and selectivity toward H+ in solution and acidic atmosphere as well as Al3+ in the presence of other cations. The fluorescence turn-on mechanism was studied and proved to be based on the CN isomerization. For these fluorescent molecules with donor-acceptor structure, their luminescent wavelength and photophysical properties can be dominated by adjusting the structure of aniline-like groups and the chain length connecting with naphthalimide. All of these fluorescent molecules emitted strong solid-state fluorescence due to their inherent twisted geometries, and exhibited excellent thermal stability, which is beneficial for their application at high temperature.