A new low band gap dithienylene-fluorovinylene electrochromic polymer: an intriguing effect of silyl substitution on the polymerisation reaction

Abstract

Trimethylsilyl substitution at the a position has been claimed to favour both the chemical and electrochemical polymerisation processes of polythiophenes. When comparing the electro-polymerisation of three related monomers we found that the above is not a general rule: the trimethylsilyl substitution does not always produce the expected results because electronic effects play an intriguing role in directing the reaction. One of the three monomers, 1,2-difluoro-1,2-bis(4-methoxy-2-thienyl)ethene, easily underwent electropolymerisation giving a new low band gap polymer with good electrochromic properties

Copy number gains in EGFR and copy number losses in PTEN are common events in osteosarcoma tumors

“…For the 4F‐PTV film, two intense irreversible electrochemical signals at about 1.62 V and −1.26 V are recorded. In particular, moving toward negative potentials, the reduction of 4F‐PTV shows a reduction peak at −1.10 V, that could be attributed to the irreversible loss of fluoride ions,37 and a more intense reduction peak at −1.26 V due to the irreversible reduction of the π‐conjugated system. These potential values are in good agreement with those reported for a thienylene‐vinylene polymer fluorinated on the vinylene units and prepared via electrochemical polymerization 37.…”

“…In particular, moving toward negative potentials, the reduction of 4F‐PTV shows a reduction peak at −1.10 V, that could be attributed to the irreversible loss of fluoride ions,37 and a more intense reduction peak at −1.26 V due to the irreversible reduction of the π‐conjugated system. These potential values are in good agreement with those reported for a thienylene‐vinylene polymer fluorinated on the vinylene units and prepared via electrochemical polymerization 37. The HOMO and LUMO energy levels of the two polymers were estimated using the equations E HOMO = − e ( E ox + 4.54) (eV) and E LUMO = − e ( E red + 4.54) (eV),38 where E ox and E red are the onset potentials for oxidation and reduction, and the electrochemical band gap E g ,EC was calculated as the difference between the HOMO and LUMO levels.…”

Synthesis and characterisation of 1,2-difluoro-1,2-bis(5-trimethylsilyl-2-thienyl)ethenes. A new family of conjugated monomers for oxidative polymerisation

“…Synthesis, characterisation and potential applications of polymers based on the building blocks described herein, have been discussed elsewhere. 34…”

Development of a novel isotype organic heterojunction diode consisting of poly{7-spiro(9-fluorenyl)cyclopentadithiophene} and poly(3-octylthiophene)

“…In recent years research impetus has been devoted in search of novel electroactive polymers with appropriate band gaps suitable for various applications like light emitting diodes, [1][2][3][4][5] electrochromic devices, [6][7][8] rechargeable batteries [9][10][11] and others. More recently much attention has been drawn towards polymeric semiconductor devices in view of their potential applications requiring low cost processing over large areas.…”