title: Hierarchical amplification of macromolecular helicity of dynamic helical poly(phenylacetylene)s composed of chiral and achiral phenylacetylenes in dilute solution, liquid crystal, and two-dimensional crystal.
abstract: Optically active poly(phenylacetylene) copolymers consisting of optically active and achiral phenylacetylenes bearing L-alanine decyl esters (1L) and 2-aminoisobutylic acid decyl esters (Aib) as the pendant groups (poly(1L(m)-co-Aib(n))) with various compositions were synthesized by the copolymerization of the optically active 1L with achiral Aib using a rhodium catalyst, and their chiral amplification of the macromolecular helicity in a dilute solution, a lyotropic liquid crystalline (LC) state, and a two-dimensional (2D) crystal on the substrate was investigated by measuring the circular dichroism of the copolymers, mesoscopic cholesteric twist in the LC state (cholesteric helical pitch), and high-resolution atomic force microscopy (AFM) images of the self-assembled 2D helix-bundles of the copolymer chains. We found that the macromolecular helicity of poly(1L(m)-co-Aib(n))s could be hierarchically amplified in the order of the dilute solution, LC state, and 2D crystal. In sharp contrast, almost no chiral amplification of the macromolecular helicity was observed for the homopolymer mixtures of 1L and Aib in the LC state and 2D crystal on graphite.
authors.affiliation: Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Chikusa-ku, Nagoya 464-8603, Japan.
authors.forename: Sousuke
authors.initials: S
authors.lastname: Ohsawa
authors.forename: Shin-ichiro
authors.initials: S
authors.lastname: Sakurai
authors.forename: Kanji
authors.initials: K
authors.lastname: Nagai
authors.forename: Motonori
authors.initials: M
authors.lastname: Banno
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Maeda
authors.forename: Jiro
authors.initials: J
authors.lastname: Kumaki
authors.forename: Eiji
authors.initials: E
authors.lastname: Yashima
mesh_terms: D000114:Acetylene / Q000031:analogs & derivatives* / Q000737:chemistry; D002942:Circular Dichroism; D050866:Liquid Crystals / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D008958:Models, Molecular; D008968:Molecular Conformation; D055620:Optical Phenomena; D012996:Solutions; D013237:Stereoisomerism
chemical_list: D012996:Solutions; C519145:poly(phenylacetylene); C044736:phenylacetylene; D000114:Acetylene