title: Chromatographic enantioseparation by poly(biphenylylacetylene) derivatives with memory of both axial chirality and macromolecular helicity.
abstract: Novel poly(biphenylylacetylene) derivatives bearing two acetyloxy groups at the 2- and 2'-positions and an alkoxycarbonyl group at the 4'-position of the biphenyl pendants (poly-Ac's) were synthesized by the polymerization of the corresponding biphenylylacetylenes using a rhodium catalyst. The obtained stereoregular (cis-transoidal) poly-Ac's folded into a predominantly one-handed helical conformation accompanied by a preferred-handed axially twisted conformation of the biphenyl pendants through noncovalent interactions with a chiral alcohol and both the induced main-chain helicity and the pendant axial chirality were maintained, that is, memorized, after complete removal of the chiral alcohol. The stability of the helicity memory of the poly-Ac's in a solution was lower than that of the analogous poly(biphenylylacetylene)s bearing two methoxymethoxy groups at the 2- and 2'-positions of the biphenyl pendants (poly-MOM's). In the solid state, however, the helicity memory of the poly-Ac's was much more stable and showed a better chiral recognition ability toward several racemates than that of the previously reported poly-MOM when used as a chiral stationary phase for high-performance liquid chromatography. In particular, the poly-Ac-based CSP with a helicity memory efficiently separated racemic benzoin derivatives into enantiomers.
authors.affiliation: Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Japan.|Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Nagoya, Japan.
authors.forename: Ryoma
authors.initials: R
authors.lastname: Ishidate
authors.affiliation: Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Ikai
authors.affiliation: Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Japan.
authors.forename: Shigeyoshi
authors.initials: S
authors.lastname: Kanoh
authors.affiliation: Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Nagoya, Japan.
authors.forename: Eiji
authors.initials: E
authors.lastname: Yashima
authors.affiliation: Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Japan.
authors.forename: Katsuhiro
authors.identifier: http://orcid.org/0000-0002-5341-8799
authors.initials: K
authors.lastname: Maeda
keywords: biphenyl; chiral stationary phase; enantioseparation; helicity induction; high-performance liquid chromatography; memory; polyacetylene