@article{oai:oist.repo.nii.ac.jp:00001881,
 author = {Qiu, Zijie and Asako, Sobi and Hu, Yunbin and Ju, Cheng-Wei and Liu, Thomas and Rondin, Loïc and Schollmeyer, Dieter and Lauret, Jean-Sébastien and Müllen, Klaus and Narita, Akimitsu},
 issue = {35},
 journal = {Journal of the American Chemical Society},
 month = {Aug},
 note = {Negatively curved nanographene (NG) 4, having two heptagons and a [5]helicene, was unexpectedly obtained by aryl rearrangement and stepwise cyclodehydrogenations. X-ray crystallography confirmed the saddle-shaped structures of intermediate 3 and NG 4. The favorability of rearrangement over helicene formation following radical cation or arenium cation mechanisms is supported by theoretical calculations. NG 4 demonstrates a reversible mechanochromic color change and solid-state emission, presumably benefiting from its loose crystal packing. After resolution by chiral high-performance liquid chromatography, the circular dichroism spectra of enantiomers 4-(P) and 4-(M) were measured and showed moderate Cotton effects at 350 nm  [Formula: see text].},
 pages = {14814--14819},
 title = {Negatively Curved Nanographene with Heptagonal and [5]Helicene Units},
 volume = {142},
 year = {2020}
}