title: Redox-Dependent Transformation of a Hydrazinobuckybowl between Curved and Planar Geometries.
abstract: A red-fluorescent heterobuckybowl with an embedded hydrazine structure was synthesized from a cyclobiphenothiazine derivative via a strained cyclobicarbazole. The hydrazinobuckybowl was found to possess bowl and twist structures in the neutral state, a shallow bowl structure in the monocation state, and a planar structure in the dication state by means of X-ray crystallographic analysis, DFT calculations, and a comparison of experimental and calculated (13) C NMR chemical shifts. The hydrazinobuckybowl is the first buckybowl that changes its geometry between curved bowl/twist structures and a planar structure depending on the oxidation state. The drastic geometrical change was possible as a result of the presence of two heteroatoms in the bowl skeleton and the multiple reversible redox reactions of the compound. Owing to the two kinds of bowl and twist conformations, the bowl-inversion dynamics of the hydrazinobuckybowl were found to follow a triple-well potential model.
authors.affiliation: Institute for Molecular Science, Myodaiji, Okazaki, 444-8787, Japan. higashi@ims.ac.jp.
authors.forename: Shuhei
authors.initials: S
authors.lastname: Higashibayashi
authors.affiliation: Institute for Molecular Science, Myodaiji, Okazaki, 444-8787, Japan.
authors.forename: Palash
authors.initials: P
authors.lastname: Pandit
authors.affiliation: Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tsukuba, 305-0801, Japan.
authors.forename: Rie
authors.initials: R
authors.lastname: Haruki
authors.affiliation: Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tsukuba, 305-0801, Japan.
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Adachi
authors.affiliation: Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tsukuba, 305-0801, Japan.
authors.forename: Reiji
authors.initials: R
authors.lastname: Kumai
keywords: cations; conformation analysis; heterobuckybowls; heterocycles; redox chemistry