Electrolyte salts tetrabutylammonium tetrafluoroborate

Tetrabutylammonium tetrafluoroborate (TBATFB, Bu4NBF4) is another excellent electrolyte for general use. Like other tetrafluoroborate salts, it is somewhat more soluble in both organic compounds and water than TBAHFP, and is more stable than TBAHFP in methylene chloride. House and coworkers have described procedures for the synthesis of TBATFB and other tetraalkyl-ammonium tetrafluoroborates [9]. Thus, a solution of 8.4 g (0.025 mol) of... 

The first study of PTh and PPy wettability was reported in 1984 [27]. Derivatives of thiophene and pyrrole were polymerized in a classical electrolytic medium, i.e. acetonitrile and tetrabutylammonium tetrafluoroborate as the electrolytic salt. The thickness of the film was approximatively 0.5 pm and the water contact angles reported (86° for PTh and 62° for PPy) indicate their hydrophilicity. These electropolymerized films have the advantage to show exceptional stability for several months. In the oxidized form, the films are ionic composites. Electrochemically... 

Eaves et al. [122] synthesized a redox-active thin film of ferrocene that was covalently attached to polypyrrole (Fig. 3). The inclusion of redox centers in the film was readily achieved by functionalizing the pyrrole nitrogen with the molecular electroactive species. The conductivities were typically 10 to 10 S cm . Golden yellow films were grown in acetonitrile with either O.l M tetrabutylam-monium perchlorate or tetrabutylammonium tetrafluoroborate added as the electrolytic salt. The films exhibited some rectifying behavior, which eventually decayed. The films could also be copolymerized with N-methylpyrrole. 

Polyselenophene (Fig. 16c) has been prepared. However, due to the difficulty in obtaining the monomer, the polymer has not been extensively investigated. Polymers of selenophene prepared electrochemically under appropriate conditions yield films with maximum conductivities of 10"- S cm [330,331]. Samples of p-doped selenophene produced chemically have conductivities on the same order of magnitude [332]. Applying 3-10 V between two electrodes in an electrolyte of 0.1 to 1 M lithium tetrafluoroborate or lithium perchlorate dissolved in benzonitrile or propylene carbonate gives polyselenophene films, as does the combination of tetrabutylammonium tetrafluoroborate in benzonitrile. However, other salts such as lithium hexafluoroarsenate, lithium hexafluorophosphate, tetrabutylammonium perchlorate, or silver perchlorate in combination with solvents such as acetonitrile or nitrobenzene were reported to produce either powders or no products at all [330,331,333]. 

The electrolyte, added to enhance conductivity and to minimize double-layer and migration current effects, is chosen on the basis of solubility in a given solvent as well as inertness toward the electroactive substance and its electrolysis products. There are of course many choices of electrolyte for use in aqueous solution. The tetraalkylammonium salts are the most commonly used non-aqueous electrolytes. Tetrabutylammonium tetrafluoroborate (TBATFB) and tetrabutylammonium hexafluorophosphate (TBAHFP) are recommended by Fry and Britton, who note that TBAHFP in acetonitrile has a particularly large useful potential range of +3.4 to —2.9 V (vs. SCE). 

A systematic study of the ion-size dependence of the electrolyte-induced spectral shifts of the p-ANTP triplet absorption band was performed. The work focused on anions because it is possible to select a relatively large set of rigid, approximately spherical negative ions. In addition, unhke the cations, they do not form specific coordination spheres in ethereal solvents. THF solutions of the fluoride, chloride, bromide, tetrafluoroborate, perchlorate, and hexafluoro-phosphate salts of the tetrabutylammonium (TBA ) cation were investigated. 

In choosing the electrolyte for electropolymerization, an important requirement is that both the anion and cation are inert to electrochemical reactions at the potentials used for polymerization. Typical electrolytes used in nonaqueous solutions are tetraalkylammonium salts such as tetrabutylammonium hexafluorophosphate, tetrafluoroborate, perchlorate, and corresponding lithium salts. 

Created electrolyte comprised of solvent and ionic species. Possible ionic species include lithium tetrafluoroborate, tetrabutylammonium perchlorate, and tetraethylammonium tetrafluoroborate. Salt most preferred is ethyltriethylammonium tetrafluoroborate preferred solvent is non-aqueous. Examples include ethylene carbonate, propylene carbonate, N-methypyrrolidione, 1,2-dimethoxyethane, methyl formate, sulfuryl chloride, and tributyl phosphate. The most preferable solvent is a nitrile, specifically propionitrile. AIM solution of MTEATFB in propionitrile yielded conductivity of 48 mS/cm at 95°C and 28 mS/cm at 23°C. 

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