title: An Obtuse-angled Corner Unit for Fluctuating Carbon Nanohoops.
abstract: The invention of corner units was the key factor that allowed the synthesis of cyclo-para-phenylenes with strained curved π-systems. Despite only a few scarce instances of the development of corner units to date, a variety of structural congeners have been synthesized. These preceding corner units commonly possessed directing angles of ≤90°, which enabled the macrocyclization of multiple units, up to six. In this study, we introduce an obtuse-angled corner unit for the synthesis of cyclo-para-phenylene congeners. The corner unit with oxanorbornadiene possessed a directing angle of 126° and thus allowed for the macrocyclization of larger structures with up to seven units. Reductive aromatization was applicable to complete the cyclo-para-phenylene structures and afforded the congeners with multiple anthracenylene panels. Structural studies with experimental and theoretical methods revealed a fluctuating structure with an intrinsic non-belt shape.
authors.affiliation: JST, ERATO, Isobe Degenerate π-Integration Project, Aoba-ku, Sendai, 980-8577, Japan.|Department of Chemistry, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Sun
authors.affiliation: Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba 6-3, Aramaki, Aoba-ku, Sendai, 980-8578, Japan.
authors.forename: Naoya
authors.initials: N
authors.lastname: Miyamoto
authors.affiliation: JST, ERATO, Isobe Degenerate π-Integration Project, Aoba-ku, Sendai, 980-8577, Japan.|Advanced Institute for Materials Research, Tohoku University, Aoba-ku, Sendai, 980-8577, Japan.
authors.forename: Sota
authors.initials: S
authors.lastname: Sato
authors.affiliation: Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba 6-3, Aramaki, Aoba-ku, Sendai, 980-8578, Japan.
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Tokuyama
authors.affiliation: JST, ERATO, Isobe Degenerate π-Integration Project, Aoba-ku, Sendai, 980-8577, Japan.|Department of Chemistry, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.|Advanced Institute for Materials Research, Tohoku University, Aoba-ku, Sendai, 980-8577, Japan.
authors.forename: Hiroyuki
authors.identifier: http://orcid.org/0000-0001-8907-0694
authors.initials: H
authors.lastname: Isobe
keywords: anthracenylene; carbon nanohoop; macrocycles; oxanorbornadiene; structure elucidation