Suppression of aggregation-induced fluorescence quenching in pyrene derivatives: photophysical properties and crystal structures

Two new pyrene-based fluorophores, namely 1-[4-(2,2-diphenylvinyl)phenyl]pyrene (PVPP) and 1,3,6,8-tetrakis[4-(2,2-diphenylvinyl)phenyl]pyrene (TPVPP), were synthesized through Suzuki coupling reaction and well characterized. PVPP successfully suppresses the fluorescence quenching of pyrene units in the solid state, displaying aggregation-induced enhanced emission. Despite the same substituent, TPVPP shows a different fluorescent behavior. On the basis of the crystal structures, the distinct optical behavior is discussed and clarified. The intermolecular C-H?π interaction has a dramatic effect on their photophysical properties in the solid state.