Arylethynyl Substituents at Plane Node of Pyrene: Synthesis, Crystal Structures, and Photophysical 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 H-1/(CNMR)-C-13, high-resolution mass spectrometry, X-ray 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.