International audienceA new copper(II) complex Cu(II)-L containing N2O2 donor atoms has been prepared from 6-[3′-(N-pyrrol)propoxy]-2-hydroxyacetophenone and diaminoethane in the presence of copper acetate monohydrate. It was characterized by spectroscopic methods such as FT-IR, UV-vis, mass spectra, elemental analysis and cyclic voltammetry. The molecular structure of Cu(II)-L has also been confirmed by X-ray diffraction analysis. The electrochemical behavior of copper(II)-Schiff base complex containing pyrrol groups has been investigated in DMF and acetonitrile solutions using cyclic voltammetry. Thus, conducting polymeric films of polypyrrole were obtained on the surfaces of glassy carbon and ITO electrodes using copper(II) complex as monomer. The modified electrodes were electrochemically and morphologically characterized and their electrocatalytic properties in heterogeneous phase have also been investigated. The AFM studies show that the morphology of polypyrrole (PPy) films on ITO-electrodes depends on the number of cyclical scans. The electrocatalytic performances of this complex seem to be more efficient towards the electro-oxidation of isopropylic alcohol than any other kinds of alcohols such as methanol, ethanol and benzyl alcohol. The electro-reduction of carbon dioxide was also examined

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In this work, a bidentate Schiff base ligand (HL) based on N and O donor heteroatoms has been used to synthesize a series of new stable metal complexes of general composition of M(L)2 with M = Mn, Ni and VO. The ligand was obtained from the condensation of 2-methoxybenzylamine with 2,3dihydroxybenzaldehyde in methanolic medium. The complexes were formed by mixing the metal acetate salts and the ligand in 1:2 molar ratio. The resulting three complexes have been characterized by different analytical techniques, including FT-IR, UV-Vis, mass spectroscopies, thermogravimetry and cyclic voltammetry, to study their molecular structure and redox/electrochemical properties. Moreover, the effect of the metal on the complexes electronic properties, and their predicted reactivity, has been studied by Density Functional Theory (DFT). The spectroscopic results suggest that the metal is bonded to the ligand through the phenolic-like oxygen and the imine-type nitrogen atoms. Electronic and vibrational absorption spectra of the nickel complex suggest a square-planar geometry around the central metal ion Ni(II), while square-pyramidal and octahedral geometry have been proposed for VO(IV) and Mn(II) complexes. The thermogravimetric analyses of the complexes confirmed the presence of water molecules in their structures and thermal decomposition led to the formation of metal oxides as residues. The voltammogram of the Ni(II) complex suggests the existence of quasi-reversible redox system in DMSO solution.

A new colorimetric receptor HL, acting as a bidentate Schiff base ligand, has been synthesized by condensation of 2-methoxybenzylamine on 2,3-dihydroxybenzaldehyde in a methanolic solution. Interestingly, this chelating agent can selectively detect Cu, Co, Fe and Fe ions with a simple and an easy-to-make, well defined naked-eye visible color changes in two different solvents like acetonitrile and methanol. This bidentate ligand coordinates three metal ions of Co(II), Cu(II) and Fe(II) via nitrogen and oxygen atoms. The molecular structures of the synthesized compounds were elucidated by various physicochemical properties such as the elemental analysis, FT-IR, HNMR, UV-Vis and the Mass spectrometry. The resulting general formulae [M(L)·HO] (M(II)=Cu, Fe, Co) are proposed as mononuclear complexes. The solvatochromism properties of these compounds were studied with their absorption spectra using different solvents as methanol (MeOH), acetonitrile (AN), tetrahydrofuran (THF), dimethylformamid (DMF), dimethylsulfoxid (DMSO) and dichloromethane (DC). The Electrochemical behavior of copper complex was explored in DMF solutions by cyclic voltammetry (CV) with two working electrodes: glassy carbon (GC) and platinum electrode (Pt). This study reveals that copper complex shows successively two redox systems as Cu and Cu. The Fe and Co redox systems have also been studied in DMF and DMSO media.

This work describes the synthesis of a new unsymmetrical tetradentate copper(ii) Schiff base complex Cu(L)(Py)(ClO4) containing N3O donor atoms.