An Intrinsic Hydroquinone-Functionalized AIE Core with Dual Sensitivity via Integrated Molecular Design

A new aggregation-induced emission (AIE) luminescence core, 1-hydroquinol-1,2,2-triphenylethene (HQTPE), has been designed and synthesized for the first time. This AIE core is amazingly simple but is fundamentally important to chemistry because of its intrinsic redox and pH activities. The incorporation of hydroquinone (HQ) moiety into a common AIE core tetraphenylethene (TPE) yields HQTPE with unique fluorescent properties over most other AIEgens so far reported. There are tremendous differences of photochemcical properties between HQTPE, 1-benzoquinol-1,2,2-triphenylethene (QTPE, the oxidized counterpart) and its anions. Interestingly, as the solution concentration is increased, AIEgen HQTPE shows stronger fluorescence but QTPE exhibits rapid quenching of fluorescence in a nonlinear fashion, which are in agreement with theoretical studies. The fluorescence of HQTPE is also highly dependent of pH value of media. We have further explored HQTPE as an ultrasensitive redox probe and efficient deoxidizer, which could lead to many potential applications in health care, food security, environmental monitoring, optic and electronic devices.