Formation of Aniline-Bonded Catechols in Aqueous Solution and Their Electrochemical Behavior at a Carbon Felt Electrode

Abstract

The oxidized form of catechol (1,2-benzoquinone) reacts with aniline at neutral pH range and the electroactive 1:1 and 1:2 compounds of catechol and aniline which exhibit separative reversible redox waves are produced and their formal electrode potentials are ¹0.05 V and ¹0.23 V, respectively. The 1:1 compound is considered to be an adduct with pink color and the 1:2 compound is considered to be two anilines substituted catechol from the MS data of molecular weight (290) and 1 H and 13 C NMR data. The 1:2 compound accumulates on the carbon electrode surface due to its affinity to the carbon felt electrode and a detection limit of this compound was found to be 5 × 10 ¹9 M.

Unprecedented Enzymatic Synthesis of Perfectly Structured Alternating Copolymers via “Green” Reaction Cocatalyzed by Laccase and Lipase Compartmentalized within Supramolecular Complexes

“…The strong presence of both signals indicate near complete oxidation of the initial mixed dimer (quinone-diamine Michael addition product) to the final repeating unit as shown in Scheme . These findings are consistent with similar reports in the literature. , …”

Electrochemical Introduction of Amino Group to a Glassy Carbon Surface by the Electrolysis of Carbamic Acid

“…Moreover, in this case, new small redox waves ͑IIa and IIc͒ appeared during a potential scan, and these redox waves remained even after the electrode was washed. As described earlier, 9 the oxidized form of catechol ͑1.2-benzoquinone͒ reacts with aniline, and anilinebonded catechol compounds show reversible or quasi-reversible redox waves. The redox waves of the adduct of amino group and 1,2-benzoquinone are observed at about −0.1 V vs Ag/AgCl, and the amino group-substituted catechol exhibits redox waves at about +0.05 V vs Ag/AgCl.…”

“…It has been reported that the oxidized form of catechol ͑1,2-benzoquinone͒ reacts with amine compounds such as aniline and dialkylamines, 8 and the redox waves of the adduct of 1,2-benzoquinone and aniline and those of the aniline-substituted catechol were reported in our previous paper. 9 If an amino group is introduced to a graphite carbon surface, an aniline-like structure may be formed. Then, similar redox waves of aniline-bonded catechol can be expected to appear when the cyclic voltammetry using a pre-electrolyzed electrode is carried out in an ammonium carbamate solution.…”