title: Nature of zinc(II)-induced ionochromic effect of bipyridine-containing conjugated polymers: an electrostatic interaction mechanism.
abstract: To reveal the nature of the zinc(II)-ion-induced ionochromic effect of bipyridine (bpy)-containing pi-conjugated polymers, we proposed an electrostatic interaction mechanism to illustrate our recent experimental findings [Tian, L., et al. J. Phys. Chem. B 2005 109 (15), 6944]. Our theoretical analysis was based on the semiempirical (INDO/2) calculation of spectral properties and electronic structures of difluorene-substituted bpy model compounds. Our calculations show that the zinc(II)-induced ionochromic effect can be attributed to the electrostatic interaction between the zinc(II) ion and the polymer. Zinc(II) ion acts as a positive point charge with varied charge quantities, which is responsible for the red-shifted absorption spectra compared with those of the metal-free compound. The counterion ionochromic effect of the zinc(II) ion is also discussed. The proposed mechanism is possibly applied to the ionochromic effect induced by other metal ions such as Cd(II) and Hg(II).
authors.affiliation: Key Laboratory for Supramolecular Structure and Materials, Jilin University, Changchun 130012, PRC.
authors.forename: Bing
authors.initials: B
authors.lastname: Yang
authors.forename: Leilei
authors.initials: L
authors.lastname: Tian
authors.forename: Houyu
authors.initials: H
authors.lastname: Zhang
authors.forename: Wu
authors.initials: W
authors.lastname: Zhang
authors.forename: Hai
authors.initials: H
authors.lastname: Xu
authors.forename: Zengqi
authors.initials: Z
authors.lastname: Xie
authors.forename: Ping
authors.initials: P
authors.lastname: Lu
authors.forename: Ming
authors.initials: M
authors.lastname: Zhang
authors.forename: Jingsheng
authors.initials: J
authors.lastname: Yu
authors.forename: Dan
authors.initials: D
authors.lastname: Lu
authors.forename: Yuguang
authors.initials: Y
authors.lastname: Ma
authors.forename: Jiacong
authors.initials: J
authors.lastname: Shen
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Liu