Investigation of catalytic effects of the proton and Lewis acids on oligomerization and chemical polymerization of pyrrole

Can, Muzaffer; Özaslan, Hayri; Işıldak, Ömer; Pekmez, Nuran Özçiçek; Yıldız, Attila

doi:10.1016/j.polymer.2004.08.003

Cited by 40 publications

(20 citation statements)

References 24 publications

(21 reference statements)

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“…Thus, we were unable to carry out electrochemical oxidations of 4 under acidic conditions directly analogous to those used in the case of the ironA C H T U N G T R E N N U N G (III)-mediated oxidative coupling. [45] Nevertheless, we feel that one key to the present electrochemical approach is that it allows coupling to take place under lower proton concentrations than those required for chemical coupling. [46] At present, it is not possible to formulate a detailed mechanism for the reactions involving the conversion of bipyrrole 4 to the isolated cyclo [8]…”

Section: Resultsmentioning

confidence: 99%

Electrochemical Syntheses of Cyclo[n]pyrrole

Buda

Iordache

Bucher

et al. 2010

Chemistry A European J

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Cyclo[8]pyrrole was obtained efficiently when 3,3',4,4'-tetraethylbipyrrole was subjected to bulk electrolysis, with yields spanning a range from close to 0 % with tetra-n-butylammonium fluoride as the electrolyte, to almost 70 % when tetra-n-butylammonium hydrogensulfate was used for this purpose. These observations are consistent with the conclusion that the reaction is controlled by anion-related factors such as a specific templating effect. Note that cyclo[8]pyrrole was the only detectable macrocyclic product obtained from 3,3',4,4'-tetraethylbipyrrole under the conditions of the electrochemical oxidation. When similar electrolyses were performed by using 3,4-diethylpyrrole as the starting material, two products could be isolated, which were identified as being the cyclo[7]pyrrole and cyclo[8]pyrrole, respectively. Detailed analyses of the oxidized forms of cyclo[7]pyrrole and cyclo[8]pyrrole revealed that under the conditions of the electrolysis these latter species are not stable.

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Section: Resultsmentioning

confidence: 99%

Electrochemical Syntheses of Cyclo[n]pyrrole

Buda

Iordache

Bucher

et al. 2010

Chemistry A European J

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“…Furthermore, spectroscopic studies have been performed and the mechanism has been followed theoretically. 77 Since the unmodified polypyrrole is insoluble in most organic solvents, various groups focused on the synthesis of soluble derivatives. In this context, for example, Ohno and Toshima carried out catalytic polymerisations of 3-butoxycarbonyl-4-methylpyrrole (108) to give the corresponding polymeric product as a soluble conducting polymer 109 (Scheme 25).…”

Section: Scheme 23mentioning

confidence: 99%

Iron(iii) chloride in oxidative C–C coupling reactions

2009

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In this critical review, the use of iron(III) chloride in oxidative C-C couplings of arenes and related unsaturated compounds is presented and reviewed. The approach allows highly selective dimerisations of phenol derivatives, naphthols, and heterocyclic compounds. Sequential couplings give access to structurally well-defined oligo- and polymers. Iron(III) chloride is commercially available and inexpensive. Being a mild oxidising agent it has been applied in numerous reactions leading to new carbon-carbon-bonds in complex molecular arrays (107 references).

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“…The excess dopant addition to the polypyrrole may lead to a lower degree of conjugation along the polymer backbone resulting in a decrease in conductivity. [9,13] The conductivity of polypyrrole decreased steeply from 2.0 to 0.2 S Á cm À1 as oxidant concentration increased (0.012 to 0.018 M). This may be due to the over-oxidation process or it may be that the kinetic effects were favored in the oxidation of pyrrole.…”

Section: Influence Of the Polymerization Conditionsmentioning

confidence: 99%

Synthesis of Polypyrrole Using Benzoyl Peroxide as a Novel Oxidizing Agent

Saravanan

Shekhar

Palaniappan

2006

Macro Chemistry & Physics

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Summary: Benzoyl peroxide is used as an oxidizing agent for the first time in the synthesis of conducting polypyrrole. Synthesis of polypyrrole is commonly performed by chemical oxidative polymerization using water‐soluble oxidizing agents. In this work, polypyrrole was prepared using organic solvent‐soluble benzoyl peroxide as an oxidizing agent in the presence of p‐toluenesulfonic acid (p‐TSA) and sodium lauryl sulfate (SLS) surfactant via the inverted‐emulsion‐polymerization technique. During polymerization, SLS is converted to dodecyl hydrogensulfate (DHS) and incorporated on to polypyrrole along with p‐TSA dopant, indicating SLS is acting as emulsifier as well as dopant. The influence of synthesis conditions such as the duration of the reaction, the temperature, the concentration of the reactants, etc., on the properties of polypyrrole was investigated to determine the optimum conditions for the synthesis of polypyrrole salt. Polypyrrole was obtained in a reaction time of 1 h with high yield (154 wt.‐% with respect to pyrrole used) and good conductivity (2 S · cm−1). The conductivity of polypyrrole‐salt was found to be nearly the same even after seven months of storage at ambient temperature (1.7 S · cm−1). magnified image

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Investigation of catalytic effects of the proton and Lewis acids on oligomerization and chemical polymerization of pyrrole

Cited by 40 publications

References 24 publications

Electrochemical Syntheses of Cyclo[n]pyrrole

Electrochemical Syntheses of Cyclo[n]pyrrole

Iron(iii) chloride in oxidative C–C coupling reactions

Synthesis of Polypyrrole Using Benzoyl Peroxide as a Novel Oxidizing Agent

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