Robert Garreau

Poly mono-, bi- and trithiophene: Effect of oligomer chain length on the polymer properties

Abstract Thiophene, 2-2′ bithiophene and 2-2′-2″ trithiophene have been electropolymerized under the same experimental conditions. Comparison of the electrical, electrochemical and spectroscopic properties of the resulting polymers reveals a steady decrease of their conjugation length as the chain length of the starting oligomer increases. These results are interpreted by the decreasing reactivity of the radical cations derived from these three substrates.

A molecular approach of poly(thiophene) functionalization

Abstract The effects of the monomer molecular structure on the properties of the resulting substituted conducting poly(thiophenes) have been analyzed with as main objective the definition of the basic structural conditions for introducing a given functionalized group while preserving the electronic and electrochemical properties of the conducting backbone. Various substitutions of the thiophene ring by linear and branched alkyl chains, ethers and aromatic groups are discussed in regard to their consequences on the electropolymerization reaction and on the electrochemical, spectroscopic and electrical properties of the resulting polymer. The conclusions of these analyses are applied to the design of highly conducting chiral poly(thiophenes). When prepared in pure enantiomeric form, these polymers present high specific rotation and are capable to recognize the two enantiomeric forms of chiral anions used as dopant during redox cycles.

Enhancement of the mean conjugation length in conducting polythiophenes

Abstract The effect of initial monomer concentration on the electrical and electrochemical properties of poly 3methyl thiophene has been analysed. This parameter allows the control of the electrical conductivity which can be varied over two orders of magnitude. These results are interpreted by the parallel formation of oligomers during the electropolymerization, which have deleterious effects on the stereoregularity of the polymer. This interpretation is confirmed by a comparative study of the electropolymerization of thiophene (T), bithiophene (BT) and trithiophene (TT). The electropolymerization of these three compounds in the same conditions leads to very different polymers. The electrochemical and spectroscopic analysis of these polymers show that the mean conjugation length decreases from PT to PTT which is in agreement with the parallel decrease of the DC conductivity.

Electrosynthesis of conducting poly-pseudo-crown ethers from substituted thiophenes

La polymerisation electrolytique du 1,14-bis (3-thienyl)-3,6,9,12-tetraoxatetradecane donne le polythiophene correspondant. Ses proprietes electrochimiques, spectroscopiques et electriques (Ω≃10 −2 S/cm) sont inferieures a celles des polythiophenes substitues en 3 par des chaines polyether

Poly(fhiorinated 3-alkyl thiophene)

Etude des proprietes electrochimiques et de la conductivite des polymeres obtenus par polymerisation electrolytique des thiophenes substitues en 3 par les groupes CH 2 -CH 2 C 6 F 13 (1) (CH 2 ) 3 C 6 F 13 (2) et (CH 2 ) 3 C 4 F 9 (3). Le polymere (3) a les proprietes les plus interessantes, analogues ou superieures a celles des poly(3-alkylthiophene)s

Selective ring-opening reaction of styrene oxide with lithium azide in the presence of cyclodextrins in aqueous media

Abstract Regioselective ring-opening of racemic styrene oxide was achieved by lithium azide in the presence of β-cyclodextrin in aqueous media. Kinetic resolution of racemic epoxide was observed and 1-phenyl-2-azido-ethanol was obtained with 78 % ee.

Enantioselective chiral poly(thiophenes)

Chiral poly(thiophenes) have been synthesized by electropolymerization; they exhibit high specific rotation, stability, and conductivity and can stereoselectively recognize chiral anions used as doping agents during voltammetric cycles.

Modification of the structure and electrochemical properties of poly(thiophene) by ether groups

Poly[3-(3,6-dioxaheptyl)thiophene] has been synthesised by electropolymerisation; this highly conducting electroactive polymer exhibits specific interactions with lithium cations.

Synthesis of 3-(polyfluoroalkyl) thiophenes

Abstract Synthese of new thiophenes having various perfluorinated alkyl groups attached via alkyl spacers to the 3-position are described. These compounds are potential monomers for the electrosynthesis of new organic conductors.

Reduction of the steric hindrance to conjugation in 3,4-disubstituted poly(thiophenes); cyclopenta[c]thiophene and thieno[c]thiophene as precursors of electrogenerated conducting polymers

The cyclopenta[c]thiophene (1) and thieno[c]thiophene (2) have been synthesized and used as substrates for electropolymerization; steric hindrances is less in poly(1) than in poly(3,4-dialkylthiophenes), while attempts to electropolymerize (2) were unsuccessful.