Anodization in oligo(ethylene glycol) as an initial derivatization tool for preparing glassy carbon electrodes covalently modified with amino compounds: effective access to a 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO)-modified glassy carbon electrode.
Anodization in HO(CH2CH2O)nH (1a, n=2; 1b, n=3; 1c, n=4) as an initial derivatization tool for preparing glassy carbon (GC) electrodes covalently modified with amino compounds was explored. As an amino compound to be immobilized, 4-amino-2,2,6,6-tetramethylpiperidinyl-1-oxyl (4-amino-TEMPO) was selected. When GC electrodes anodized at 2.0 V vs. Ag wire coated with AgCl in 1 containing RCH2CH2SO3Na (2a, R=H; 2b, R=OH) were treated with a N,N-dimethylformamide (DMF) or CH2Cl2 solution of 4-amino-TEMPO and 1,3-dicyclohexylcarbodiimide (DCC), TEMPO-modified GC electrodes were afforded. Coverage (gammaTEMPO) of the electrode surfaces by TEMPO was estimated by cyclic voltammetry in CH3CN containing NaClO4. A TEMPO-modified GC electrode with the best gammaTEMPO (1.36 x 10(-10) mol/cm2) was obtained by anodization in 1b containing 2a at the expense of 3.0 C followed by amidization in DMF for 7 d. On cyclic voltammetry, the TEMPO-modified GC electrode showed good and stable electrocatalytic ability for oxidation of allyl alcohol in the presence of 2,6-lutidine.
Maeda
H
H
Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Japan. h-maeda@phs.osaka-u.ac.jp
Saka-iri
Y
Y
Ogasawara
T
T
Huang
C Z
CZ
Yamauchi
Y
Y
Ohmori
H
H
D002244:Carbon; D003497:Cyclic N-Oxides; D004563:Electrochemistry; D004566:Electrodes; D007202:Indicators and Reagents; D011092:Polyethylene Glycols / Q000737:chemistry*
D003497:Cyclic N-Oxides; D007202:Indicators and Reagents; D011092:Polyethylene Glycols; D002244:Carbon; C003959:TEMPO