Highly Emissive Double π‐Helical Molecular Carbons via Nitrogen Integration

ABSTRACT

Improving the emission efficiency of chiral π‐systems is of significance for their practical applications in materials science. Herein, we report a family of highly emissive double π‐helical molecular carbons featuring a cyclooctatetraphenylene (COTt) or cyclooctahexaphenylene (COTh) core. In contrast to previously reported non‐emissive tetrabenzo‐COTt derivatives, the introduction of nitrogen via diarylamine/carbazole fusion leads to fluorescence quantum yields as high as 98%. The high configurational stability of these double π‐helices enabled successful chiral resolution of their enantiomers using high‐performance liquid chromatography. Notably, structural evolution from the COTt to the COTh core results in an approximately three‐fold increase in the luminescence dissymmetry factor ( g _lum ), while the circularly polarized luminescence (CPL) brightness reached 110 M ⁻¹  cm ⁻¹ , among the highest values reported for cyclooctatetraene (COT)‐based chiral molecular carbons. Theoretical calculations further support these results, revealing large electric transition dipole moments ( | μ | ) and perfect parallel/antiparallel alignment between the μ and magnetic transition dipole moments ( m ). Our work provides valuable insight into the molecular design of high luminescent chiral emitters.