Octagon-Embedded Carbohelicene as a Chiral Motif for Circularly Polarized Luminescence Emission of Saddle-Helix Nanographenes Medel Miranda, Miguel Ángel Tapia Martín, Rubén Blanco Suárez, Víctor Miguel Álvarez, Delia Morcillo Martínez, Sara Patricia González Campaña, Araceli Chirality Circularly polarized luminescence Helicenes We report a new family of hexa-peri-hexabenzocoronene (HBC)-based helical nanographenes incorporating π-extended carbo[5]helicenes bearing an octagonal carbocycle. This family represents a new kind of highly distorted saddle-helix hybrid nanographenes. For the first time, the eight-membered ring becomes a constituent of both a carbo[5]helicene and a HBC and thus, the negative curvature is responsible for twisting both units. This novel chiral motif, namely, oct-[5]helicene results in the largest torsion angle recorded so far for a carbo[5]helicene (θ=79.5°), as it has been suggested by DFT-calculations and confirmed by X-ray crystallography. Consequently, the barriers of isomerization become exceptionally high for a [5]helicene unsubstituted in the fjord region since neither racemization nor decomposition were observed at 200 °C for 1 or 3 during 5 h. Therefore, racemic resolutions allowed subsequent chiroptical studies showing the ECD and CPL responses of this novel family of chiral nanographenes. 2022-11-28T11:06:17Z 2022-11-28T11:06:17Z 2020-12-18 journal article Medel, MA et al. Octagon-Embedded Carbohelicene as a Chiral Motif for Circularly Polarized Luminescence Emission of Saddle-Helix Nanographenes. Angew. Chem. Int. Ed., 2021, 60, 6094-6100 https://hdl.handle.net/10481/78152 10.1002/anie.202015368 eng http://creativecommons.org/licenses/by-nc-nd/4.0/ open access Attribution-NonCommercial-NoDerivatives 4.0 Internacional