AIE‐Active Difluoroboron Complexes with N,O‐Bidentate Ligands: Rapid Construction by Copper‐Catalyzed C−H Activation

Abstract

Abstract The development of organic materials with high solid‐state luminescence efficiency is highly desirable because of their fundamental importance and applicability in optoelectronics. Herein, a rapid construction of novel BF2 complexes with N,O‐bidentate ligands by using Cu(BF4)2•6H2O as a catalyst and BF2 source is disclosed, which avoids the need for pre‐composing the N,O‐bidentate ligands and features a broad substrate scope and a high tolerance level for sensitive functional groups. Moreover, molecular oxygen is employed as the terminal oxidant in this transformation. A library of 36 compounds as a new class of BF2 complexes with remarkable photophysical properties is delivered in good to excellent yields, showing a substituent‐dependency on the photophysical properties, derived from the π–π* character of the photoexcited state. In addition, aggregation‐induced emission (AIE) is observed and quantified for the brightest exemplars. The excited state properties are fully investigated in solids and in THF/H2O mixtures. Hence, a new series of photofunctional materials with variable photophysical properties is reported, with potential applications for sensing, bioimaging, and optoelectronics.

Keywords

• aggregation‐induced emission
• BF2 complexes with N,O‐bidentate ligands
• CH activation
• copper catalysis
• solid‐state fluorescence