Poly(3-arylthiophenes):  Syntheses of Monomers and Spectroscopic and Electrochemical Characterization of the Corresponding Polymers

Abstract

Several arylthiophene derivatives were synthesized using the Kumada cross-coupling reaction and electropolymerized at a platinum electrode with the aim of investigating the effect of the number of thiophene unit and substitution pattern of the monomers on the spectroscopic and charge storage properties of the resulting polymers. The electrochemical oxidation of these monomers showed a decrease of the anodic peak potential as the number of thiophene units is increased: 1.2−1.4, 1.0, and 0.75 V for the mono-, bi-, and terthiophene, respectively. The polymers having one phenyl ring per thiophene unit displayed a larger band gap with the exception of poly-3-phenyl-thiophene, which showed a much smaller band gap. The lower band gap for the later can be explained by the higher reactivity of the cation radical (as evidenced by a high oxidation potential) which led to a highly conjugated polymer. The cyclic voltammograms of the same polythiophene derivatives is characterized by a significant charge unbalance between the doping and undoping charge and most showed a limited cycle lifetime. On the other hand, poly-3-phenyl thiophene, poly-3‘-(1-naphthyl)-2,2‘:5‘,2‘ ‘-terthiophene are the more stable and also show a relatively good balance between doping and undoping charge for both the p- and n-doping redox processes. The highest voltammetric charge density evaluated by considering the weight of monomer unit was recorded for poly-3-phenyl thiophene despite the fact that some poly terthiophene derivatives have a lower phenyl ring/thiophene unit ratio.

A review of electrode materials for electrochemical supercapacitors

“…151 For polythiophenes, the relatively poor stability of the n-doped state could lead to a continuous decrease of its ES performance upon cycling. 152,153 As shown by P. Sivaraman et al, the specific capacitance of the poly(3-methyl thiophene)(PMeT) ES could be decreased by 16.2% during the first 200 cycles. 138 Another report showed that the PMeT polymer, which was synthesized with a template by electrochemical polymerization of 3-methyl thiophene, decreased by B16% the specific capacitance of the PMeT/PVDF|PC/EC/1 M LiClO 4 |PMeT/PVDF ES (type III) within 150 cycles.…”

Rapid-scan time-resolved FT-IR spectroelectrochemistry – Study on the electron transfer of ferrocene-substituted thiophenes

“…In the literature [8,12], CV and Osteryoung square waver voltammetry (OSWV) were used to evaluate the redox properties, the degree of interaction and the possibility of ''electronic communication" among the ferrocene centers. Recently, there is a growing interest in the spectroelectrochemistry studies on these complexes [10,[13][14][15], UV-Visible and in situ FT-IR spectroscopy were most widely used to investigate the mechanism of electron transfer. Although a good amount of experimental and theoretical work has been done on such complexes, a lot more remains to be performed.…”

ortho-Tetraaryls as helical building blocks: a study of structure, theory, electrochemistry, and optical properties

“…7 Specifically, the previous study emphasized spectroscopic and charge storage properties of poly(2) and related monomers. However, the focus of this prior report did not provide a detailed property analysis of monomer 2, nor was the electrical conductivity profile of poly (2) reported.…”

“…7 Interestingly, the stability of the 2 1þ can be gleaned from the fact that FAB-MS reveals an M þ molecular ion (as opposed to MH þ ). For comparative purposes, the linear analog, 5,5 0 -biphenyl-2,2 0 -bithiophene (compound 4) was also prepared using a similar Kumada 8 coupling strategy.…”