Modification of conventional electrodes by coating the surface with polymer films containing redox sites is of interest in electrocatalysis, 1 and many transition metal complexes have been electropolymerized for such purposes. [2][3][4][5][6][7][8][9] Another strategy to prepare modified electrodes with redox polymer films is to deposit polymer films having the ability to fix the redox species from solution via electrostatic attraction or complexation. [10][11][12][13][14][15][16] Polymeric films of Cu(II), Co(II) complexes of Schiff bases were prepared by Abdel-Azzem et al. 17,18 and tested for electrocatalytic reduction of some imino compounds. In searching for new monomer candidates for preparation of modified electrodes, Schiff bases containing free aromatic amine moiety for polymerization seem to be promising for electrodeposition of electroactive polymer films with the ability to fix metal cations via complexation in the present study. The Schiff base obtained by the condensation reaction between 1,8-diaminonaphthalene and dehydroacetic acid, namely, 8-(3-acetylimino-6-methyl-2,4-dioxopyran)-1-aminonaphthalene (AMDAN), according to Scheme 1, was anodically polymerized. The resulting electroactive polymer films were characterized by elemental analysis, thin-layer chromatography, IR, proton nuclear magnetic resonance ( 1 H NMR), and 13 C NMR. ExperimentalThe chemicals lithium perchlorate, 1,8-diaminonaphthalene, dehydroacetic acid, acetonitrile, perchloric and sulfuric acids, and pyridine were analytical grade chemicals (Aldrich) and used without further purification. Aqueous solutions were prepared from bidistilled water. Electrochemical measurements were performed using the EG&G PAR computer measuring system (model 250) and a Hewlett-Packard X-Y recorder (model 7440). A three-electrode electrolytic cell (Bioanalytical system, model C-1A) with a platinum disk electrode (3.0 mm diam) was used as working electrode, a plat-inum sheet (area 2 cm 2 ) as counter electrode, and a Ag/AgCl reference electrode.Schiff base AMDAN (80% yield) was prepared according to the recommended method 19 by the condensation reaction between 1 mol 1,8-diaminonaphthalene and 1 mol dehydroacetic acid. The dehydroacetic acid in ethanol was added dropwise with stirring to hot 1,8-diaminonaphthalene in ethanol. The resulting Schiff base 20 was recrystallized twice from ethanol as faint brown granules, melting point 218ЊC. The structure of Schiff base AMDAN was confirmed by IR, 1 H NMR, 13 C NMR, and elemental analyses. IR spectra were recorded on a Gemini 2000 MHz spectrophotometer in deuterated dimethyl sulfoxide (DMSO), and 13 C NMR spectra were recorded on a Bruker AC-200 E spectrometer. Chemical shifts are reported as ␦ in ppm referenced to external tetramethylsilane (TMS).IR absorption spectra of Schiff base AMDAN give peaks at 3400 cm Ϫ1 corresponding to NH 2 group, 1680, 1690 cm Ϫ1 corresponds to keto and ester groups, respectively, 1640-1600 cm Ϫ1 corresponds to CϭC, 1650 cm Ϫ1 due to CϭN. 1 H NMR (DMSO-d 6 ):
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