Synthesis and Spectroscopic and Electrochemical Characterisation of a Conducting Polythiophene Bearing a Chiralβ-Substituent: Polymerisation of (+)-4,4′-Bis[(S)-2-methylbutylsulfanyl]-2,2′-bithiophene

Abstract

A regioregular head-to-head/ tail-to-tail poly(beta,beta'-disubstituted bithiophene) P1 was synthesised by chemical and electrochemical polymerisation of 2,2'-bithiophene that bears (S)-2-methylbutylsulfanyl chains in the beta and beta'-positions. The polymer was characterised by GPC, NMR and UV/Vis spectroscopy, CD, AFM and by electrochemical and conductivity measurements. The CD spectra of P1 in solutions in which poor solvents are present show interesting features and allow the presence of different optically active species to be distinguished. Upon varying the casting conditions of P1, different relative amounts of grainy and homogeneous aggregated phases were observed in AFM micrographies of films and corresponding negative or positive first Cotton effects were found in the CD spectra. AFM, CD and UV/Vis characterisations were also performed on an electrogenerated optically active polymer PE1, in order to make a comparison with the chemically synthesised one. The interesting, small band gap of P1 allows for easy p- and n-electrochemical doping.

Polymers with Alkylsulfanyl Side Chains for Bulk Heterojunction Solar Cells: Toward a Greener Strategy

“…The more pronounced red‐shifted shoulders (at about 610 and 690 nm) in the P2 spectra indicate that, even in solution, polymeric chains are partially in a planar conformation, characterized by a conjugation band with a typical vibronic structure. This planar conformation is usually attributable to the formation of some aggregates due to strong interchain π‐stacking interactions, favored by the higher molecular weight.…”

Chiral BEDOT-based copolymers prepared by chemical and electrochemical polymerization

“…We confirmed macroscopic spiral structure of the polymers in optical microscope and scanning electron microscope [5]. Although there have been reports on production of chiral thiophene derivatives by electrochemical polymerization method in isotropic electrolyte such as water or acetonitrile, there has been no report of electrochemical polymerization of chiral PEDOT [6]. In this study we report the synthesis and characterization of chiral BED-OT-based copolymers, obtained by the chemical and electrochemical polymerization of (R), (S)-1,4-bis[2-(3,4-ethylenedioxy)thienyl]-2,5-benzoic acid octyl ester [BEDOT-B(OCT Ã )].…”

Electro- and Magneto-Responsible Chiral Polymers

“…The AFM of the 25 film showed a grainy and homogeneous aggregated phase and the corresponding negative or positive first Cotton effects were found in the CD spectra. The interesting, small band gap of 25 allows for easy p-and nelectrochemical doping [71]. The chiroptical properties of the polythiophene bearing two chiral alkyl side chains (26) in a solution, an aggregate, and a thin solid film state were investigated.…”