Synthesis of disulfide-containing aniline and copolymerization with aniline

A novel disulfide-containing aniline, 1,4-dihydrobenzo[d][1,2] dithiin-5-ylamin (1), was synthesized by the alkylbromination of 1,2-dimethyl-3-nitrobenzene, followed by the formation of a disulfide bond via thioesterification and then the reduction of the nitro group. The monomer showed a reductive and oxidative potential of the disulfide bond at -0.63 and 1.25 V (vs Ag/Ag⁺), respectively. Although the monomer showed the oxidative potential of aniline at 0.85 V (vs SCE), the electro- or chemical-oxidative polymerization of the monomer resulted in the formation of only the oligomer, suggesting that the disulfidecontaining condensed ring would prevent further propagation of the polymerization due to steric hindrance. However, the nearly ideal copolymerization of 1 with aniline (An) was carried out by chemical oxidative polymerization. The resulting copolymers (1/An = 1/1 and 2/1, by mole) had weight-averaged molecular weights (M̄_w) of 10 000 and 6600, respectively, and good redox activities coupled with those of the polyaniline and disulfide group. The copolymer showed conductivities of 5.1 × 10^-2 S/cm for 1/1 and 1.3 × 10^-2 S/cm for 2/1 after being redoped with camphorsulfonic acid. It is suggested that these copolymers might be good candidates for the cathode materials of secondary polymer batteries.