Helical Trilayer Nanographenes with Tunable Interlayer Overlaps

The synthesis of well-defined nanocarbon multi-layers, beyond the bilayer structure, is still a challenging goal. Herein, two trilayer nanographenes were synthesized by covalently linking nanographene layers through helicene bridges. The structural characterization of the trilayer nanographenes revealed a compact trilayer-stacked architecture. The introduction of a furan ring into the helicene linker modulates the interlayer overlap and pi-conjugation of the trilayer nanographenes, enabling the tuning of the interlayer coupling, as demonstrated by optical, electro-chemical, and theoretical analyses. Both synthesized trilayer nanographenes are rigid chiral nanocarbons and show a chirality transfer from the helicene moiety to the stacked nanographene layers. These helical trilayer nanographenes reported here represent the covalently linked multilayer nanographenes rather than bilayer ones, showing the tunable multilayer stacking structure.

Automated summary

In this study, two trilayer nanographenes were synthesized by covalently linking nanographene layers through helicene bridges, and their compact trilayer-stacked architecture was characterized. By introducing a furan ring into the helicene linker, the interlayer overlap and pi-conjugation of the trilayer nanographenes can be modulated, enabling tunable interlayer coupling. The synthesized trilayer nanographenes exhibit rigid chirality transfer from the helicene moiety to the stacked nanographene layers, representing covalently linked multilayer nanographenes with a tunable multilayer stacking structure.