n-Alkyl Group-Substituted Poly(m-aniline)s: Syntheses and Magnetic Properties

Preparation of n-alkyl group-substituted derivatives of poly(m-aniline) that we have proposed as a possible organic ferromagnetic polymer has been attempted. We started from the syntheses of the monomers, n-alkyl-substituted m-bromoanilines (R = methyl, ethyl, hexyl, dodecyl, and hexyloxy groups). The approximate solubilities of the methyl, ethyl, and hexyloxy group-substituted polymers in N-methyl-2-pyrrolidone (NMP) were nearly equal to that of poly(m-aniline). On the other hand, hexyl- and dodecyl-substituted polymers have high solubilities in the conventional organic solvents such as acetone, dichloromethane, and so forth. The ferromagnetic spin correlation was observed in the polymer oxidized by NOBF₄ in the temperature range above 50 K The average total spin quantum number was determined to be 1.0 at 2 K. Moreover, in all polyradical samples, a weak antiferromagnetic interaction between spin clusters was observed at very low temperatures probably due to a conformational change in the present poly(m-aniline) derivatives.