N. Saito, Takakazu Yamamoto
Jun 1, 1995
Citations
0
Influential Citations
20
Citations
Journal
Macromolecules
Abstract
Dehalogenation polycondensations of 2,6-dichloro-1,5-naphthyridine with isolated zerovalent nickel complex and electrochemically generated zerovalent nickel complex afford π-conjugated poly(1,5-naphthyridine-2,6-diyl) (P(2,6-N)) in high yields. The electrochemical polymerization gives the polymer as a thin film on the electrode. UV-visible data indicate that P(2,6-N) has, among poly(naphthalene)-like π-conjugated polymers, the longest effective π-conjugation system along the polymer chain due to its less sterically hindered structure to form the π-conjugation system. Electrochemical reduction of P(2,6-N) takes place at E° = -1.79 V vs Ag/Ag + , the value revealing that P(2,6-N) belongs to the most easily reducible π-conjugated conducting polymers reflecting a very strong π-electron-deficient nature of the 1,5-naphthyridine ring. As for poly(naphthalene-2,6-diyl)-type polymers, introduction of every imine nitrogen leads to a shift of the reducing potential to the positive side by 0.3-0.4 V. Chemically reduced (or n-doped) P(2,6-N) with sodium naphthalide gives a dark blue adduct, which exhibits electrical conductivity of 1.8 x 10 -2 S cm -1 . The electrochemical reduction of a cast P(2,6-N) film causes a color change with the appearance of a new broad adsorption band in a near-infrared region.