title: Double-Stranded Helical Oligomers Covalently Bridged by Rotary Cyclic Boronate Esters.
abstract: Novel double helices covalently bridged by cyclic boronate esters were synthesized from complementary dimers with an m-terphenyl backbone joined by a chiral or achiral phenylene linker bearing diethyl boronates and diols, respectively. The X-ray crystallographic analysis and variable-temperature NMR and circular dichroism measurements, along with theoretical calculations, revealed that the double helices function as a "molecular rotor" in which the cyclic boronate ester units rotate, yielding two stable rotamers at low temperatures. Moreover, our data indicates that the covalently bonded double helices can undergo a unique helix-inversion simultaneously with a rotational motion of the boronate esters.
authors.affiliation: Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Chikusa-ku, Nagoya, 464-8603, Japan.|Department of Chemistry, Interdisciplinary Graduate School of Science and Engineering, Shimane University, 1060 Nishikawatsu, Matsue, 690-8504, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Iida
authors.affiliation: Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Chikusa-ku, Nagoya, 464-8603, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Ohmura
authors.affiliation: Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Chikusa-ku, Nagoya, 464-8603, Japan.
authors.forename: Ryuta
authors.initials: R
authors.lastname: Noda
authors.affiliation: Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Chikusa-ku, Nagoya, 464-8603, Japan.
authors.forename: Soichiro
authors.initials: S
authors.lastname: Iwahana
authors.affiliation: Graduate School of Science and Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata, 992-8510, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Katagiri
authors.affiliation: Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Chikusa-ku, Nagoya, 464-8603, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Ousaka
authors.affiliation: Institute of Transformative Bio-Molecules (WPI-ITbM) and Department of Chemistry, Graduate School of Science, Nagoya University, Nagoya, 464-8602, Japan.
authors.forename: Taku
authors.initials: T
authors.lastname: Hayashi
authors.affiliation: Institute of Transformative Bio-Molecules (WPI-ITbM) and Department of Chemistry, Graduate School of Science, Nagoya University, Nagoya, 464-8602, Japan.
authors.forename: Yuh
authors.initials: Y
authors.lastname: Hijikata
authors.affiliation: Institute of Transformative Bio-Molecules (WPI-ITbM) and Department of Chemistry, Graduate School of Science, Nagoya University, Nagoya, 464-8602, Japan.
authors.forename: Stephan
authors.initials: S
authors.lastname: Irle
authors.affiliation: Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Chikusa-ku, Nagoya, 464-8603, Japan.
authors.forename: Eiji
authors.initials: E
authors.lastname: Yashima
keywords: chirality; double helix; helical structures; helix inversion; molecular rotors