Medel, Miguel ACruz, Carlos MMiguel, DeliaBlanco, VictorMorcillo, Sara PCampaña, Araceli G2025-01-072025-01-072021-08-25https://hdl.handle.net/10668/27668A new family of chiral saddle-helix hybrid nanographenes is reported. The first hexa-peri-hexabenzocoronene (HBC) analogues bearing a nine-membered carbocycle are presented. Furthermore, for the first time, π-extended carbo[n]helicenes containing a nine-membered ring as part of the helical moiety have been synthesized. The combination of a [5]helicene moiety and a nonagon ring in a single chiral motif induces a tremendous distortion from planarity into the nanographenic structures compared to other saddle-helix hybrids such as heptagon- and octagon-containing π-extended carbo[5]helicenes. In fact, the interplanar angle of the two terminal rings reaches the largest angle (134.8°) of a carbohelicene reported to date, thus being by far the most twisted helicene yet prepared. Photophysical properties evaluation showed improved absorption dissymmetry factors (|gabs |=4.2×10-3 ) in the new family of nonagon-containing π-extended carbo[5]helicenes.enAttribution-NonCommercial 4.0 Internationalhttp://creativecommons.org/licenses/by-nc/4.0/chiralityhelicenesnanographenesnonagonal carbocyclepolycyclic aromatic hydrocarbonsresearch article34329498open access10.1002/anie.2021093101521-3773PMC8518755https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/anie.202109310https://pmc.ncbi.nlm.nih.gov/articles/PMC8518755/pdf