Novel Aromatic Polymers with Pentafluorophenyl Pendent Groups

Abstract

A novel series of linear, high-molecular-weight polymers was synthesized by one-pot, superacid-catalyzed reaction of pentafluorobenzaldehyde (PFBA) (1) with nonactivated aromatic hydrocarbons: biphenyl, diphenyl ether, p-terphenyl, 4,4′-diphenoxybenzophenone, and 1,3-bis- and 1,4-bis(4′-phenoxybenzoyl)benzenes. The reactions were performed at room temperature in the Bronsted superacid trifluoromethanesulfonic acid (CF3SO3H, TFSA) and in a mixture of TFSA with methylene chloride. The polymer-forming reaction was highly dependent upon the acidity of the reaction medium, as judged from the molecular weights of the polymers obtained. A possible reaction mechanism is suggested. The polymers obtained were soluble in the common organic solvents, and flexible transparent films could be cast from the solutions. 1H and 13C NMR analyses of the polymers synthesized revealed their linear structure. The pendent pentafluorophenyl groups react regioselectively with nucleophiles under basic conditions in polar, aprotic so...