Tetraphenyl-1,4-dioxin and Tetraphenyl-pyrane-4-one: Old Molecules, New Insights.

Aggregation-induced emission (AIE) is a phenomenon where certain molecules or materials become highly luminescent when they aggregate or come together in a condensed state, such as a solid or a solution. Moreover, new molecules which show AIE properties are designed and synthesized for various applications like imaging, sensing, and optoelectronics. 2,3,5,6-Tetraphenylpyrazine (TPP) is one of the well-established examples of AIE. Herein, 2,3,5,6-tetraphenyl-1,4-dioxin (TPD) and 2,3,4,5-tetraphenyl-4 H -pyran-4-one (TPPO), which are old molecules with TPP similarity, were studied, and new insights in terms of structure and aggregation-caused quenching (ACQ)/AIE properties were gained by means of theoretical calculations. Those calculations performed on TPD and TPPO aimed to provide a better understanding of their molecular structures and how they affect their luminescence properties. This information could be used to design new materials with improved AIE properties or to modify existing materials to overcome ACQ.