π‐Extended Heli(aminoborane)s with Highly Bright Circularly Polarized Luminescence and Narrowband Emission

Abstract Helical molecular carbons (HMCs) possess high absorption/luminescence dissymmetry factors ( g abs / g lum ) and significant luminescence quantum yield ( Φ lum ), resulting in a high circularly polarized luminescence (CPL) brightness ( B CPL ), which is essential for the development of CPL materials for practical applications. Herein, we designed and synthesized a series of boron‐nitrogen (BN)‐doped HMCs, named π‐extended heli(aminoborane)s ( E[10]HAB‐A , E[10]HAB‐B and E[10]HAB‐C ), consisting of laterally π‐extended [10]helicene skeleton with alternating N and B atoms at the inner rim. The aromaticity, electronic structures, and photophysical properties of E[10]HAB‐A/B/C were systematically investigated through experiments and theoretical calculations. E[10]HAB‐A/B/C displayed remarkable photophysical properties, including high molar extinction coefficient and bright narrowband emission. The isolated enantiomers of E[10]HAB‐A/B/C exhibited intense circular dichroism (CD) and CPL, in which E[10]HAB‐A shows g abs and g lum values up to 0.024 and 0.017, simultaneously with high Φ lum of 82 % and a narrow full width at half maximum of 16 nm. Accordingly, E[10]HAB‐A exhibits a B CPL as high as 583 M −1 cm −1 , which is the largest value among the reported BN‐doped HMCs. Our study indicates that inner rim BN‐doping and π‐extension are effective strategies to achieve high Φ lum and balanced g lum values in HMCs.