TY - JOUR
T1 - A new organic redox species-indole tetraone trapped MWCNT modified electrode prepared by in-situ electrochemical oxidation of indole for a bifunctional electrocatalysis and simultaneous flow injection electroanalysis of hydrazine and hydrogen peroxide
AU - Mayuri, Pinapeddavari
AU - Huang, Sheng Tung
AU - Mani, Veerappan
AU - Kumar, Annamalai Senthil
N1 - Generated from Scopus record by KAUST IRTS on 2023-09-21
PY - 2018/4/1
Y1 - 2018/4/1
N2 - Indole and its derivatives are important core constituents of several natural, biological and pharmaceutical relevant compounds. In general, electrochemical oxidation of indole on solid electrodes in acid and non-aqueous conditions results in the formation of polyindole like compounds as an end product. Selective and controlled electrochemical oxidation of indole and its derivatives to redox active intermediate compound/s without over-oxidation to the polymeric product is a challenging research task. Herein, we report an electrochemical oxidation of electro-inactive indole to a multi-redox active Indole Tetraone (1H-Indole-2,3,4,7-Tetraone)-a new organic redox species (Ind-Tetraone) and entrapment as a surface-confined redox active species on multiwalled carbon nanotube modified glassy carbon electrode (GCE/MWCNT@Ind-Tetraone) in physiological pH solution. GCE/MWCNT@Ind-Tetraone showed a well-defined surface-confined redox peaks at E1/2, −0.270 V (A1/C1) and +0.270 V (A2/C2) vs Ag/AgCl. From the physicochemical characterizations by Raman and IR spectroscopy, XPS, LC-MS (an ethanolic extract) and control electrochemical experiments with various substituted indole derivatives, it is confirmed the formation of Ind-Tetraone species without any polyindole formation upon the electrochemical oxidation of indole on MWCNT surface. Electrochemical oxidation of nitrogen atom as a radical species and subsequent electron-transfer/water addition reaction is proposed as a possible mechanism for the Ind-Tetraone product formation. A simultaneous electrocatalytic oxidation of hydrazine and reduction reaction of hydrogen peroxide at two discreet potentials has been demonstrated as a bifunctional application of the GCE/MWCNT@Ind-Tetraone system. In further, the GCE/MWCNT@Ind-Tetraone as a electrochemical detector, simultaneous flow injection analysis of hydrazine and hydrogen peroxide was also demonstrated as a proof of concept for the bifunctional application.
AB - Indole and its derivatives are important core constituents of several natural, biological and pharmaceutical relevant compounds. In general, electrochemical oxidation of indole on solid electrodes in acid and non-aqueous conditions results in the formation of polyindole like compounds as an end product. Selective and controlled electrochemical oxidation of indole and its derivatives to redox active intermediate compound/s without over-oxidation to the polymeric product is a challenging research task. Herein, we report an electrochemical oxidation of electro-inactive indole to a multi-redox active Indole Tetraone (1H-Indole-2,3,4,7-Tetraone)-a new organic redox species (Ind-Tetraone) and entrapment as a surface-confined redox active species on multiwalled carbon nanotube modified glassy carbon electrode (GCE/MWCNT@Ind-Tetraone) in physiological pH solution. GCE/MWCNT@Ind-Tetraone showed a well-defined surface-confined redox peaks at E1/2, −0.270 V (A1/C1) and +0.270 V (A2/C2) vs Ag/AgCl. From the physicochemical characterizations by Raman and IR spectroscopy, XPS, LC-MS (an ethanolic extract) and control electrochemical experiments with various substituted indole derivatives, it is confirmed the formation of Ind-Tetraone species without any polyindole formation upon the electrochemical oxidation of indole on MWCNT surface. Electrochemical oxidation of nitrogen atom as a radical species and subsequent electron-transfer/water addition reaction is proposed as a possible mechanism for the Ind-Tetraone product formation. A simultaneous electrocatalytic oxidation of hydrazine and reduction reaction of hydrogen peroxide at two discreet potentials has been demonstrated as a bifunctional application of the GCE/MWCNT@Ind-Tetraone system. In further, the GCE/MWCNT@Ind-Tetraone as a electrochemical detector, simultaneous flow injection analysis of hydrazine and hydrogen peroxide was also demonstrated as a proof of concept for the bifunctional application.
UR - https://linkinghub.elsevier.com/retrieve/pii/S0013468618304110
UR - http://www.scopus.com/inward/record.url?scp=85042505503&partnerID=8YFLogxK
U2 - 10.1016/j.electacta.2018.02.107
DO - 10.1016/j.electacta.2018.02.107
M3 - Article
SN - 0013-4686
VL - 268
SP - 150
EP - 162
JO - Electrochimica Acta
JF - Electrochimica Acta
ER -