Electropolymerization of indole and its 5- position-substituted derivatives in the mixed electrolytes of acetic acid and boron trifluoride diethyl etherate

Abstract

The mixed electrolyte of acetic acid and boron trifluoride ethyl ether (BFEE), containing poly(ethylene glycol) with a molar mass of 1000 (PEG1000), was employed for the electrochemical synthesis of indole and its 5-position-substituted derivatives, such as 5-cyanoindole, 5-nitroindole, indole-5- carboxylic acid, and 5-hydroxyindole. The introduction of acetic acid into BFEE increased both the solubility of PEG1000 and the ionic conductivity of the well mixed electrolyte. In this medium, highquality polyindole (PIN) and its derivatives were successfully electrodeposited via anodic oxidation of their corresponding monomers. The as-formed PINs exhibited good electrochemical behavior and good fluorescence properties.