An Edge-Boron-Doped Nanographene with a C54B2 Core: Narrowband Red Fluorescence and Amplified Spontaneous Emission

A boron-doped nanographene (NG) featuring a C54B2 π skeleton with an edge-boron-doping mode was designed and synthesized. Detailed comparative studies on the edge- and internal-boron-doped NG molecules reveal that their distinct electronic structures and physical properties are remarkably contributed by the boron-doping modes. Notably, this edge-boron-doped NG displays the blue-shifted absorption, narrowband red fluorescence, and amplified spontaneous emission characteristic, together with weakened electron-accepting ability and disturbed aromaticity. This study thus gains insight into the boron-doping electronic effects and verifies the efficacy of the carbon-radical-directed boron-doping design, which will be useful for construction of other heterocyclic π-electron systems.