Electrosyntheses of freestanding polyindole films in boron trifluoride diethyl etherate

Abstract

High-quality freestanding polyindole (PIn) films were synthesized electrochemically through the direct oxidation of indole in pure boron trifluoride diethyl etherate (BFEE). The oxidation potential of indole in this medium was measured to be only 0.86 V versus a saturated calomel electrode, which was lower than that determined in acetonitrile/0.1 mol L Ϫ1 Bu 4 NBF 4 . PIn films obtained from this medium showed better electrochemical behavior and better thermal stability with a conductivity of 10 Ϫ1 S cm Ϫ1 , and this indicated that BFEE was a better medium than acetonitrile for the electrosyntheses of PIn films. Structural studies showed that the polymerization of indole ring occurred at the 2,3-position. As-formed PIn films could be partly dissolved in acetone, acetonitrile, tetrahydrofuran, and so forth. Fluorescent spectral studies indicated that PIn was a good blue-light emitter. To the best of our knowledge, this is the first report on the fluorescence of PIn.

Electrochemical Polymerization of Carbazole in Acetic Acid Containing Boron Trifluoride Diethyl Etherate

“…Successive cyclic voltammograms of 0.02 mol•L -1 carbazole in acetic acid containing 26% BTDE and 5% PEG400 (by volume) on the Pt electrode are shown in Figure 2. Similar to the results during the electrosyntheses of other conducting polymers such as polyindoles, 23 polyfluorenes, 24 etc., the CV of carbazole in this mixed electrolyte shows good redox peaks. PCz was reduced and oxidized between 0.53 and 0.7 V and the oligomer was oxidized at 0.75 V. The increase of the redox wave currents implied that the amount of the polymer on the electrode increased successively.…”

Electrodeposition of High-quality Polycarbazole Films in Composite Electrolytes of Boron Trifluoride Diethyl Etherate and Ethyl Ether

“…Under these circumstances, BFEE serves not only as the solvent but also as the supporting electrolyte and no other supporting electrolyte is needed. On the other hand, investigations on the electrochemical polymerization of fused ring compounds, such as thianaphthene [42], naphthalene [43], benzofuran [44] and indole [45], have been carried out in BFEE. However, as far as we know there have been no reports on the electrochemical polymerization of carbazole in BFEE.…”

Electrochemical copolymerization of indole and 3‐methylthiophene

“…12,16 P3MeT film changed its color from pale-blue in the doped state to red in the dedoped form. For the copolymer, its color changed from yellow green in the doped state to darkish redbrown color in the dedoped state.…”

“…12,13 Therefore, PIn may be a good candidate for applications in various domains like electronics, electrocatalysis, and anticorrosion coatings. However, PIn has relatively low electrical conductivity, close to 10 À1 S cm À1 in the doped state, [14][15][16] which may inhibit its applications. On the other hand, P3MeT, as an important derivative of polythiophene, has led to numerous applications in the areas of microelectronics, 17 optoelectronics, and sensors 18 owing to its high conductivity and high tensile strength and flexibility.…”

“…On the other hand, electroactive copolymers with improved physical and chemical properties obtained from In with different monomers have also been electrochemically synthesized. 13,28,29 It is well known that high quality free-standing films of P3MeT 30 and PIn 16 can be produced by direct anodic oxidation of corresponding monomers in boron trifluoride diethyl etherate (BFEE). The interactions between the middle strong Lewis acid, BFEE, and the aromatic monomers lower their oxidation potentials and the catalytic effect of BFEE facilitates the formation of high quality freestanding P3MeT and PIn films.…”