title: Chirality responsive helical poly(phenylacetylene) bearing L-proline pendants.
abstract: A novel, optically active, cis-transoidal poly(phenylacetylene) bearing an L-proline residue as the pendant group (poly-1) was prepared by the polymerization of the corresponding monomer using a rhodium catalyst in water, and its chiroptical property was investigated using circular dichroism spectroscopy. Poly-1 showed intense Cotton effects in the UV-visible region of the polymer backbone in water, resulting from the prevailing one-handed helical conformation induced by the covalent-bonded chiral L-proline pendants and exhibited a unique helix-sense inversion in response to external, achiral, and chiral stimuli, such as the solvent and interactions with chiral small molecules. We found that poly-1 could enantioselectively trap 1,1'-2-binaphthol within its hydrophobic helical cavity inside the polymer in aqueous media and underwent an inversion of its helical sense in the presence of one of the enantiomers. The effect of the optical purity of 1,1'-2-binaphthol on the chiroptical properties of poly-1 was also investigated.
authors.affiliation: Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Chikusa-ku, Nagoya 464-8603, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kawamura
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Takeyama
authors.forename: Miho
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kurihara
authors.forename: Kazuhide
authors.initials: K
authors.lastname: Morino
authors.forename: Eiji
authors.initials: E
authors.lastname: Yashima
mesh_terms: D000114:Acetylene / Q000031:analogs & derivatives* / Q000737:chemistry; D002384:Catalysis; D002942:Circular Dichroism / Q000379:methods; D005663:Furans / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D008968:Molecular Conformation; D011108:Polymers / Q000737:chemistry; D011392:Proline / Q000737:chemistry*; D012238:Rhodium / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D013237:Stereoisomerism; D014050:Toluene / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D005663:Furans; D011108:Polymers; D012997:Solvents; D014867:Water; C044736:phenylacetylene; D014050:Toluene; C018674:tetrahydrofuran; D011392:Proline; D012238:Rhodium; D000114:Acetylene