title: Regioregulated Syntheses of Poly(aminopyridine)s by Pd-catalyzed Amination Reaction.
abstract: Regioregulated poly(aminopyridine)s were synthesized by a Pd-catalyzed CN coupling reaction. The polymerization using Pd(0) and a bulky monodentate phosphine ligand distinctively produced the para-linked and meta-linked poly(aminopyridine)s, without the need for a protection process. The regioregularity of the polymer was confirmed by (1) H NMR spectroscopy. Model reactions were studied to evaluate the possibility of crosslinkage in the polymer. A large difference in reactivity was observed between 5-amino-2-bromopyridine and 2-amino-5-bromopyridine, which should have afforded same product. Density functional theory (DFT) calculations indicated that electron densities of the Br-bound carbon atom and the pyridine-nitrogen atom determine the reactivity of the monomers.
authors.affiliation: Tsukuba Research Center for Interdisciplinary Materials Science (TIMS), Graduate School of Pure and Applied Science, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba 305-8573, Japan.
authors.forename: Junpei
authors.initials: J
authors.lastname: Kuwabara
authors.forename: Hironori
authors.initials: H
authors.lastname: Mori
authors.forename: Takuya
authors.initials: T
authors.lastname: Teratani
authors.forename: Munetaka
authors.initials: M
authors.lastname: Akita
authors.forename: Takaki
authors.initials: T
authors.lastname: Kanbara