[4]Triangulenes with Three Oxygen-Boron-Oxygen (OBO) Units and Anti-Kasha Emissions

Abstract

Triangulenes have attracted enormous interest due to the intriguing properties. However, the limited synthetic approach and intrinsic instability make the investigation of their properties inaccessible. The synthesis of heteroatom-doped triangulenes becomes an alternative strategy of studying triangulenes. Herein, we report the synthesis of three [4]triangulenes, which are edge-modified by three oxygen-boron-oxygen (OBO) units. The structure of OBO-doped [4]triangulene is confirmed by the single-crystal X-ray diffraction analysis, revealing an off-plane core with three edge-modified OBO units. These OBO-doped [4]triangulenes exhibit high stability towards air and moisture. Both theoretical calculations and photophysical investigation of OBO-doped [4]triangulenes indicate that this kind of molecules display anti-Kasha fluorescence and phosphorescence emissions. The binding behaviors of (OBO)3-[4]triangulenes toward pyridine were also studied.