Achieving aggregation-induced emission and remarkable mechanochromic luminescence based on a tetraphenylethene modified quinoline derivative

A simple tetraphenylethene (TPE) modified quinoline derivative TPE-QL was designed and prepared. It possessed donor-acceptor molecular structure and highly twisted conformation, which could be proved by spectral studies and theoretical calculatiuons. Due to the introduction of TPE unit, TPE-QL exhibited typical aggregation-induced emission (AIE) characteristic. Interestinly, TPE-QL also showed obvious fluorescence response to mechanical force by changing the emission wavelength from 440 nm to 485 nm upon grinding. Moreover, reversible mechanochromic behavior was detected after repeated grinding and fuming treatment. This work not only discovered a new AIE-active mechanochromic material, but also provided possibility for its application in the filed of ink-free rewritable papers for security decumentation purposes.