Electrooxidative polymerization

Synthesis of Poly(phenylene Oxides) by Electrooxidative Polymerization of Phenols... 

While dicarboxylic acid-functional pyrroles have received only cursory attention in condensation polymerizations, other derivatives have been studied extensively. Pyrrole itself has been electrooxidatively polymerized (81CS145) to give a flexible conductive film, presumably containing poly(2,5-pyrrolediyl) units (23) as the main structural feature. The blue-black polymer obviously contains other functionality, as evidenced by elemental analysis and by the fact that it carries a partial positive charge, and it exhibits p-type conductivities approaching the metallic range (e.g. 100 fi-1 cm-1). The main utility of poly(pyrrole) (23) has been for the modification of electrode surfaces, although numerous other applications can be envisioned. 

Yamamoto K., Kimihisa A., Asada T., Nishide H., Tsuchida E. (1988) Preparation of Poly(/ -phcnylcne) by Electrooxidative Polymerization in Acid Media. Bull Chem Soc Jap. 61, 5,1731-1734. 

Poly(oxy-1,4-phenylene) is obtained by electrooxidative polymerization of / -bromo-phenol in aqueous NaOH solution. The yield increases when aqueous NaOH is replaced by aqueous KOH or when the reaction is conducted at higher temperature. In contrast, p-chlorophenol electrooxidatively dimerizes to give the biologically and pharmacologically important dioxin, 2,7-dichlorodibenzo[, ][l,4]dioxine254. In an effort to find protective chemical coatings, electrooxidative polymerization of ra-chlorophenol and ra-bromophenol was observed255. 

Nevertheless, Mattes s group and Fuchigami s group achieved independently electrooxidative polymerization of pyrrole, thiophene, and aniline in different moisture stable imidazolium ionic liquids [38 0]. Mattes s group used 1-butyl-... 

Fuchigami and his coworkers employed [EMIM][OTf] for the electropolymeri-zation. They found that the polymerization of pyrrole in the ionic liquid proceeds much faster than that in conventional media like aqueous and acetonitrile solutions containing 0.1 M [EMIM][OTf] as a supporting electrolyte, as shown in Figure 8.7. It is known that in the radical-radical coupling, further oxidation of oligomers and polymer deposition in the electrooxidative polymerization are favorably affected because the reaction products are accumulated in the vicinity of the electrode surface under slow diffusion conditions, and consequently the polymerization rate is increased. It is reasonable to assume that the polymerization rate in [EMIM][OTf] is higher than that in the conventional media, since neat [EMIM][OTf] (viscosity ... 

Finally in this section it is worth noting that the oxidative coupling of phenols may be extended to form interesting polymers. Thus electrooxidative polymerization of phenol using basal-plane pyrolytic graphite electrodes gives thin black polymer films which are electrically conducting. ... 

Another approach uses a cobalt tetrakis(o-aminophenyl)porphyrin polymer film, prepared by electrooxidative polymerization of the monomer on top of the electrode as conductive film-mediator-couple [19]. 

Sekiguchi, K., Atobe, M., and Fuchigami, T. (2003). Electrooxidative polymerization of aromatic compounds in l-ethyl-3-methylimidazolium trifluoromethanesulfonate room-temperature ionic liquid./. Electroanal. Chem., 557, pp. 1-7. 

Atobe, M., S. Hitose, and T. Nonaka. 1999. Chemistry in centrifugal fields Part I. Electrooxidative polymerization of aniline. Electrochem Commun 1 278. 

By the same manner, the electropolymerization of the copper complex of 80 (half-unit = 2,6-diacetylpyridine-mono(ethylene(liamine)) was performed, which led to an electroactive polymeric Him whose electrocatalytic properties towards biodegradable agrochemicals were evaluatedOne can cite the example of the electrooxidative polymerization of 81, a 3-[l-(2-amino-phenylimino)-ethyl]-6-methylpyran-2,4-dione Schiff base. The corresponding films are insoluble in most solvents, electroactive in water but electro-inactive in acetonitrile and they display electrocatalytic properties towards the oxidation of hydroquinone . ... 

Lelj, F., G. Morelli, G. Ricciardi, and A. Rosa (1990). The electrochemical behaviour and electrooxidative polymerization of tetraazannulenic alkyl- and aryl-cobalt complexes. Inorg. Chim. Acta 176, 189-194. 

Yousef, U.S. Electrooxidative polymerization of 3-[l-(2-amino-[henylimino)-ethyl]-6-methylpyran-2,4-dione Schiff base in acetonitrile and redox properties of the resulting platinum-film modified electrodes. Eur. Polym. J. 35, 133-143. 

Synthesis PVTPA was produced by free-radical polymerization of 4-vinyl-triphenylamine the electrode was then coated with this polymer using an evaporation technique, and finally the electrooxidation results in the dimer form shown above [711]. PTPA was synthesized by the electrooxidative polymerization of triph-enylamine in acetonitrile/TBAPFe [711]. 

Monomers 1, 2, and 4 are very insoluUe in almost all organic solvent. Thus we had to explore non-traditional solvent systems to effect our electropolymerization. 1, 2, and 4 were found to be soluble in CH2CI2 and 1,2 dichloroethane with small amounts (<5% v v) of TFA. Trifluoroacetic acid and TEA in CH2CI2 have been shown to stabilize radical cations formed during oxidation (34). Since die conductivity of this solution was low, we added 0.1 M TBAPF6, and subsequent excursions to oxidative potentials showed no clear oxidation peaks nor any products precipitating onto the electrodes. We reasoned that PFe maybe acid labile, so we synthesized triethylammonium trifluoroacetate as a supporting electrolyte and added TFA to solubilize the monomer. This solvent electrolyte system provided an excellent media for die electrooxidative polymerization of 1,2, and 4. 

Electrooxidative polymerization of pyrrole, thiophene, and aniline was achieved in various imidazolium ionic liquids [26-28]. l-Butyl-3-methylimidazolium tetrafluoroborate and hexafluorophosphate ([BMIM])[BF4] and [BMIM] [PFe]) for electropolymerization and notably 7i-conjugated polymers thus obtained are highly stable, and they can undergo electrochemical doping and dedoping in the ionic liquids up to million cycles. In addition, the polymers have cycleswitching speeds as fast as 100 m. 

Atobe M, Kaburagi T, Nonaka T (1999) Ultrasonic effects on electroorganic processes. XIII. Role of ultrasonic cavitation in electrooxidative polymerization of aniline. Electrochem 67 1114—1116... 

Electrooxidative polymerization of pyrrole was performed on the FDH-adsorbed electrode in a solution containing 0.1 M pyrrole and 0.1 M KC1 under anaerobic conditions at a potential of 0.7 V. The thickness of polypyrrole membrane was controlled by coulometry. After washing with distilled water the PP/FDH/Pt electrode was kept in Mcllvaine buffer of pH 4.5 at 4 C for several hours until further experiments commenced. 

---