Xps studies of some chemically synthesized polypyrrole organic acceptor complexes

Abstract

Photoexcitation of N-ethylcarbazole (donor) in the presence of a polymer having terephthalate chromophores (acceptor) in solution produces a terephthalate anion radical in the polymer. The stability of the terephthalate anion radical (TP−) in the polymer chain was investigated by the anion radical transfer method using nanosecond laser photolysis. The samples were poly(vinyl methyl terephthalate) (PVMTP), copolymers of vinyl methyl terephthalate (VMTP) with vinyl acetate (VAc), and the monomer model compound, dimethyl terephthalate (DMTP). The anion radical TP− formed in the homopolymer, PVMTP does not transfer an electron to 1, 4-dicyanobenzene (DCNB), but the monomer model compound, DMTP does, although the two systems have the same transient absorption spectrum. As for the anion radical TP− in the copolymer, the anion radical transfer to DCNB has two components, a fast and a slow component: The fast component has a rate constant of 7.7×108 M−1 s−1 and the slow component is extremely slow. The fraction of the slow component increases with the VMTP fraction. The results show that the neighboring interactions of TP residues in the polymer chain stabilize the anion radical of the TP residue. The anion radical TP− formed in the polymer is stabilized partly due to neighboring interactions and partly due to the steric hindrance of the polymer chain to an approaching DCNB. © 1988 The Society of Polymer Science, Japan.