The Electrochemical Polymerization Of 1,2-subtituded Benzene

o-dihydroxybenzene, o-dimethoxybenzene and 1-hydroxy-2-methoxybenzene and other 1,2-subtituded benzenes were electrochemically polymerized in boron trifuoride diethyl etherate (BFEE). The corresponding polymers were characterized, respectively.1. A novel conducting polymer poly(o-dihydroxybenzene) (PoDHB) film was synthesized electrochemically by the direct anodic oxidation of o-dihydroxybenzene (oDHB) in boron trifuoride diethyl etherate. The oxidation potential onset of PoDHB 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). PoDHB films obtained from this medium showed good electrochemical behavior and good thermal stability. IR, NMR, and theoretical studies showed that the polymerization of oDHB occurred at the 4,5-position. Fluorescent spectral studies indicated that PoDHB was a good blue-light emitter, with an excitation wavelength maximum of 350 nm. In comparison with oDHB, the electrochemical polymerization of its isomers m-dihydroxybenzene, p-dihydroxybenzene, and hydroxybenzene failed under the same conditions.2. A novel conducting polymer poly (o-dimethoxybenzene) (PoDMOB), as a derivative of polyacetylene, was electrosynthesized successfully by direct anodic oxidation Of o-dimethoxybenzene (oDMOB) in boron trifuoride diethyl etherate (BFEE). The oxidation onset of oDMOB was initiated at 0.92 V versus a saturated calomel electrode (SCE), which was much lower than that determined in acetonitrile (ACN) containing 0.1 mol·L^-1 tetrabutylammonium tetrafluoroborate (TBATFB) (1.56 V vs. SCE). PoDMOB films obtained from BFEE showed good electrochemical behavior and good thermal stability with a conductivity of 0.06 S·cm^-1. IR, NMR and theoretical studies showed that the polymerization of oDMOB occurred at 4,5-position. Fluorescent spectral studies indicated that both doped and dedoped PoDMOB were blue-light emitters, with excitation wavelength maximum of 346 nm and 347 nm, respectively.3. The electrochemical polymerization of 1-hydroxy-2-methoxybenzene (HMOB) was performed in boron trifuoride diethyl etherate (BFEE) and a novel conducting polymer poly (1-hydroxy-2-methoxybenzene) (PHMOB), as a derivative of polyacetylene, were easily electrodeposited. The oxidation onset of HMOB was initiated at 0.97 V versus a saturated calomel electrode (SCE), which was much lower than that determined in acetonitrile (ACN) containing 0.1 mol·L^-1 tetrabutylammonium tetrafluoroborate (TBATFB) (1.39 V vs. SCE). PHMOB films obtained from BFEE showed good electrochemical behavior and good thermal stability with a conductivity of 0.06 S·cm^-1. IR, NMR and theoretical studies showed that the polymerization of HMOB occurred at C₄ and C₅ position. Fluorescent spectral studies indicated that doped and dedoped PHMOB were good blue-light emitters, with the same excitation wavelength maximum of 348 nm.4. 2,2-dimethyl-1,3-benzodioxole (DMMDOB) has been electropolymerized in boron trifuoride diethyl etherate and a novel conducting polymer poly(2,2-dimethyl-1,3-benzodioxole) (PDMMDOB) was electrodeposited. The oxidation onset of DMMDOB was initiated at 0.7 V versus a saturated calomel electrode (SCE), which was much lower than that determined in acetonitrile (ACN) containing 0.1 M tetrabutylammonium tetrafluoroborate (TBATFB) (1.57 V vs. SEE). PDMMDOB films obtained from BFEE showed an electrical conductivity of 0.23 S·cm^-1. IR, NMR and theoretical studies showed that the polymerization of DMMDOB occurred at C₄ and C₅ position.5. Other 1,2-subtituded benzenes with either electron donating groups (2-methyl-phenol, o-xylene, 9,10-dihydrophenanthrene, 1,2,4,5-tetramethylbenzene, o-dithiol-benzene, o-diaminobenzene) or electron-withdrawing groups (o-difluoro benzene, o-dichlorobenzene, o-dibromobenzene, o-diiodobenzene, o-dicyanobenzene, o-dinitrobenzene) are very difficalt to be electropolymerized in pure BFEE.