Electrochemical Polymerization ofo-Dihydroxybene and Characterization of Its Polymers as Polyacetylene Derivatives

A novel conducting polymer poly( o -dihydroxybenzene) (P o DHB) film was synthesized electrochemically by the direct anodic oxidation of o -dihydroxybenzene ( o DHB) in boron trifuoride diethyl etherate. The oxidation potential onset of P o DHB in this medium was measured to be only 0.66 V versus a saturated calomel electrode (SCE), which was much lower than that determined in acetonitrile containing 0.1 mol L -1 tetrabutylammonium tetrafluoroborate (1.1 V vs SCE). P o DHB films obtained from this medium showed good electrochemical behavior and good thermal stability. IR, NMR, and theoretical studies showed that the polymerization of o DHB occurred at the 4,5-position, which made P o DHB a derivative of polyacetylene. The P o DHB film was thoroughly soluble in the strong polar organic solvents dimethyl sulfoxide, ammonia, and tetrahydrofuran and partly soluble in pure ethanol. Fluorescent spectral studies indicated that P o DHB was a good blue-light emitter, with an excitation wavelength maximum of 350 nm. The thermoelectric properties of as-formed P o DHB were also determined. In comparison with o DHB, the electrochemical polymerization of its isomers m -dihydroxybenzene, p -dihydroxybenzene, and hydroxybenzene failed under the same conditions. To the best of our knowledge, this is the first paper reporting that high-quality conducting polymer films of P o DHB can be electrodeposited.