AIEE active stilbene based fluorescent sensor with red-shifted emission for vapor phase detection of nitrobenzene and moisture sensing

A unique pi-electron rich stilbene-based sensor with significantly enhanced red-shifted fluorescence emission has been synthesized via a Mizoroki-Heck cross-coupling reaction. The strong fluorescence properties of stilbene derivative as a potential fluorescent sensor have been investigated for sensitive and selective detection of haz-ardous and threatening nitrobenzene (NB) in both solution and vapor phase. The fluorescence emission intensity of stilbene sensor 1 at 474 nm was quenched upon interaction with NB. The fluorescence quenching was attributed to the combined effect of dominant smaller and adjustable size of NB and photo-induced electron transfer (PET) process. Stilbene sensor 1 is the first active bathochromic shifted fluorescent sensor with AIEE property was developed for both solution and vapor phase detection of NB. Possible interactions of stilbene sensor 1 with NB was evaluated by UV-vis., fluorescence, density functional theory (DFT) calculations, and 1H NMR titration experiment. Additionally, non-covalent interaction (NCI), Frontier molecular orbitals (FMOs) and interaction energy were studied by using Gaussian 09 software. Moreover, test strips were fabricated to accomplish contact mode detection of NB. Further, stilbene sensor 1 was successfully applied for trace detection of NB in real water samples.

Automated summary

A novel stilbene-based sensor with enhanced red-shifted fluorescence emission was synthesized for sensitive and selective detection of nitrobenzene. The fluorescence intensity of the sensor was quenched upon interaction with nitrobenzene, which was attributed to the combined effect of the smaller size of nitrobenzene and photo-induced electron transfer process. This study provides a new approach for the detection of nitrobenzene in solution and vapor phase using an active bathochromic shifted fluorescent sensor with AIEE property.