Influence of Carbazolyl Groups on Properties of Piezofluorochromic Aggregation-Enhanced Emission Compounds Containing Distyrylanthracene

Distyrylanthracene derivatives (AnPCz and AnPCz(3)) with monocarbazolyl and tricarbazolyl groups were synthesized and characterized via nuclear magnetic resonance, mass spectrometry, elemental analysis, photoluminescence, ultraviolet absorption, wide-angle X-ray diffraction, and other techniques. Another compound, distyrylanthracene (AnP), without any carbazolyl group was synthesized for comparison. The results show that the piezofluorochromic properties of the three aggregation-enhanced emission (AEE) compounds were significantly influenced by the variety of carbazolyl groups in the molecular structures. Compounds AnPCz and AnPCz(3) exhibited distinct piezofluorochromic properties and switched reversibly upon grinding-annealing or grinding-fuming. The piezofluorochromic activity can be greatly enhanced by the introduction of carbazole groups in the distyrylanthracene AEE structure. The general structure-property relationships established in this study will help researchers to identify and synthesize more piezofluorochromic materials.