Anthracene-based derivatives: Synthesis, photophysical properties and electrochemical properties

Abstract

A series of anthracene-based derivatives, namely, 9-(4-phenyl)anthracene(1), 9-(4-phenylethynyl)-anthracene(2) and 9, 10-bis(phenylethynyl)anthracene(3), was synthesized by the Suzuki/Sonogashira cross-coupling reactions in good yields. These compounds were fully characterized by X-ray crystallography, thermogravimetric analysis(TGA), differential scanning calorimetry(DSC), UV-Vis absorption and fluorescence(FL) spectroscopy, as well as density functional theory(DFT) calculations. Single-crystal X-ray analysis revealed that the packing structures were influenced by the terminal substitutions. All the compounds exhibited high thermal stability(T d=221—484 °C) and blue emission with a high quantum yield(Φ f =0.20—0.75). As the number of substituents increased, the decomposition temperatures(T d) of these compounds increased in the following order: 1<2<3. Experiments on the photophysical properties revealed that different substituents strongly affected the optical properties. In particular, compound 1b with the electron-withdrawing group(—CHO) exhibited a larger Stokes shift(113 nm) than the other compounds. Investigation of the electrochemical properties of these compounds showed that the HOMO-LUMO energy gaps(E gap) decreased obviously as the degree of conjugation increased.