Synthese et caracterisation de complexes bases de schiff contenant un residu moleculaire electropolymerisable electrodes modifiees et application a l’electrolyse en phase supportee

Abstract

Three dihydroxylatedacetophenone derivatives 2,6-(1a), 2,5-(2a), and 2,4-dihydroxyacetophenone (3a)) were O-monoalkylated using 3-bromopropyl-N-pyrrole. Thus, these monomers 6-[3’-N pyrrolpropoxy]-2-hydroxyacetophenone (1b), 5-(3’-N-pyrrolpropoxy)-2-hydroxyacetophenone (2b) and 4-(3’-N-pyrrolpropoxy)-2-hydroxyacetophenone (3b) were characterized with UV–Vis, FT-IR, NMR1H, 13C, Dept135 and elemental analysis. These monomers were electrodeposited on glassy carbon (GC) and Indium tin oxide (ITO) conductive electrodes by anodic oxidation to yield their poly(pyrrole) films. So, these new materials of electrode were characterized by cyclic voltammetry while the morphology of these films was studied by FT-IR spectroscopy, scanning electron microscopy (SEM), dispersive energy X-ray spectroscopy (EDX) and atomic force microscopy (AFM). These pyrrolic compounds were chosen as electropolymerizable units to elaborate poly(pyrrole) films containing metallic centres. In this case, a new pyrrole-Ni(II)- and Cu(II)-Schiff base complexes, derived from 2,6- (1b) and 1,2-diaminoethane, were synthesized and electropolymerized onto GC and ITO electrode surfaces. The efficiency of the electrochemical polymerization was investigated as a function of several parameters such as the nature of the electrode surface, the number of voltammetric scans, electrochemical processes produced on the electrode surfaces and the scan rate applied. The polymers, which were electrodeposited onto ITO substrates, were characterized by X-ray diffraction (XRD) and by AFM. Interesting catalytic properties towards oxidation of alcohols, reduction of iodobenzene and CO2 have been also investigated.