@article{oai:nagoya.repo.nii.ac.jp:02002099,
 author = {Hanida, Kensuke and Kim, Jinseok and Fukui, Norihito and Tsutsui, Yusuke and Seki, Shu and Kim, Dongho and Shinokubo, Hiroshi},
 issue = {38},
 journal = {Angewandte Chemie International Edition},
 month = {Sep},
 note = {s-Indacene is a classical non-alternant hydrocarbon that contains 12 π-electrons in a cyclic π-conjugation system. Herein, we report its nitrogen-doped analogue, 1,5-diaza-s-indacene. 1,5-Diaza-s-indacenes were readily prepared from commercially available 2,5-dichlorobenzene-1,4-diamine through a two-step transformation consisting of a palladium-catalyzed Larock cyclization with diaryl acetylenes followed by hydrogen abstraction. The thus obtained 1,5-diaza-s-indacenes exhibited distinct antiaromaticity, as manifested in clear bond-length alternation, a forbidden HOMO–LUMO transition, and a paratropic ring current. As compared to the parent s-indacene, the 1,5-diaza-s-indacenes showed higher electron-accepting ability owing to the presence of imine-type nitrogen atoms. The 1,5-diaza-s-indacene core is effectively conjugated with the peripheral aryl groups, which enables fine-tuning of the absorption spectra and redox properties. The two possible localized forms of 1,5-diaza-s-indacene were compared in terms of their energetic aspects.},
 pages = {20765--20770},
 title = {Antiaromatic 1,5-Diaza-s-indacenes},
 volume = {60},
 year = {2021}
}