Asymmetric Saddle-Shaped Nanographenes Integrating Helicene and Heptagon Motifs: Synthesis and Chiroptical Properties

Three curved heptagon-embedded nanographenes bearing a [5]/[6]helicene motif (<b>5</b>, <b>7</b>, and <b>11</b>) have been successfully synthesized through a Scholl-type oxidative cyclodehydrogenation. Single-crystal X-ray diffraction indicated that the introduction of helicene significantly induces pronounced distortion. The enantiomers of <b>11</b> with a high isomerization barrier of 38.54 kcal/mol based on DFT calculation were successfully resolved and displayed mirror-image circular dichroism and circularly polarized luminescence spectra.