Mechanofluorochromism and photopatterning properties of triphenylamine based acylhydrazone derivatives with aggregation-induced emission

Two types of novel symmetric acylhydrazone derivatives (TPAPT and 1,4-BDH) with triphenylamine substituted terminal groups containing one acylhydrazone and two acylhydrazone groups, respectively, were designed and synthesized. TPAPT didn't show aggregation induced emission (AIE) behaviors, whereas 1,4-BDH exhibited uncommon AIE behaviors. TPAPT exhibited obviously reversible MFC behavior, the emission wavelength changed from 452 nm to 486 nm upon grinding, accompanied by fluorescence color change. However, MFC behavior was not observed for 1,4-BDH. The reason for such different MFC behavior was that the different hydrogen bonding patterns induced the different self-assembly crystalline structures. In addition, both TPAPT and 1,4-BDH exhibited significant photo-responsive behaviors.