No abstract

To suppress the fluorescence quenching of pyrene in the aggregation state, this article presents a facile strategy for the construction of pyrene-based aggregation-induced emission luminogens (AIEgens) via decorating the pyrene core with benzophenone units at the 1-, 2-or 2,7-positions. This set of pyrene-based compounds 1-3 displayed a weak deep blue fluorescence in solution, but an enhanced excimer emission with λ em max of 426-436 nm in the aggregation state. Interestingly, unlike reported benzophenone derivatives, this series of compounds did not exhibit thermally activated delayed fluorescence/ phosphorescent properties.

Pyrene derivatives with substituents at 2-or 2,7-positions have an exceptional electronic structure due to the nodal plane at these two positions. Herein, a series of linear-shaped pyrene derivatives 1-3 were designed and synthesized via combining (4-tert-butylphenyl)ethynyl & (4-tert-butylphenyl) substituents at 2-and 7-position by using the Pd-catalysis coupling reaction with high yield. The molecular structures are completely confirmed by 1 H/ 13 CNMR, high-resolution mass spectrometry, Xray single crystal diffraction technology, etc. Indeed, compared to reported arylethynyl substituents pyrenes, the 2,7-substituted molecules 2 and 3 exhibited a deep blue emission (CIE y < 0.04) with considerable quantum yield both in solution and in the solid-state. X-ray crystallographic results indicated that the molecular pattern has a considerable impact on the emission behavior of the synthesized derivatives. In addition, theoretical studies of compounds 1-3 were also preformed to understand the relationship between molecular structure and photophysical features.