Synthesis of Highly Luminescent Chiral Nanographene.

Chiral nanographenes with both high fluorescence quantum yields (Φ ) and large dissymmetry factors (g ) are essential to the development of circularly polarized luminescence (CPL) materials. However, most studies have been focused on the improvement of g , whereas how to design highly emissive chiral nanographenes is still unclear. In this work, we propose a new design strategy to achieve chiral nanographenes with high Φ by helical π-extension of strongly luminescent chromophores while maintaining the frontier molecular orbital (FMO) distribution pattern. Chiral nanographene with perylene as the core and two dibenzo[6]helicene fragments as the wings has been synthesized, which exhibits a record high Φ of 93 % among the reported chiral nanographenes and excellent CPL brightness (B ) of 32 M  cm .