A Triskelion-Shaped Saddle-Helix Hybrid Nanographene

Abstract

A unique rippled nanographene consisting of 52 fused rings is presented in which six out-of-plane motifs are fully fused into a triangular aromatic surface with a size of approximately 2.5 nm. Three units of an unprecedented fully lateral π-extended octabenzo[5]helicene together with three units of saddle-shaped heptagonal rings are combined in a single structure, leading to a well-soluble warped nanographene. The two diastereomeric pairs of possible enantiomers were isolated, and their linear, non-linear, and chiroptical properties were evaluated, revealing outstanding quantum yield and brightness values at low energy, together with good chiroptical responses in both absorption and emission.

Keywords: circularly polarized luminescence; helicenes; nanographenes; nanostructures; nonlinear optics.