title: Helical structures of N-alkylated poly(p-benzamide)s.
abstract: Poly(p-benzamide)s 1 bearing a chiral side chain on the nitrogen atom were synthesized by chain-growth polycondensation methodology. The polyamides exhibited well-defined molecular weights with narrow polydispersities. Solutions of the polyamides in several organic solvents (CH(3)CN, CHCl(3), and CH(3)OH) showed dispersion type CD signals characteristic of coupled-oscillator and much larger as compared with the corresponding monomer. The CD signals were dependent on the temperature and molecular weight of the polyamides but independent of the solvent, as far as examined. An exciton model analysis of the absorption and CD spectra provided a clear-cut picture for the secondary structure of these polyamides in solution that the N-alkylated poly(p-benzamide)s possess a right-handed helical conformation ((P)-helix). In the solid states, the results of X-ray crystallographic analysis of 4-(methylamino)benzoic acid oligomers substantiated that they have a helical conformation with three monomer units per turn.
authors.affiliation: Synthesis and Control, PRESTO, Japan Science and Technology Agency (JST), Department of Applied Chemistry, Kanagawa University, Rokkakubashi, Kanagawa-ku, Yokohama 221-8686, Japan.
authors.forename: Aya
authors.initials: A
authors.lastname: Tanatani
authors.forename: Akihiro
authors.initials: A
authors.lastname: Yokoyama
authors.forename: Isao
authors.initials: I
authors.lastname: Azumaya
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Takakura
authors.forename: Chikashi
authors.initials: C
authors.lastname: Mitsui
authors.forename: Motoo
authors.initials: M
authors.lastname: Shiro
authors.forename: Masanobu
authors.initials: M
authors.lastname: Uchiyama
authors.forename: Atsuya
authors.initials: A
authors.lastname: Muranaka
authors.forename: Nagao
authors.initials: N
authors.lastname: Kobayashi
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Yokozawa