Synthesis, characterization, electrochemical properties and conversions of carbon dioxide to cyclic carbonates mononuclear and multinuclear oxime complexes using as catalyst

Abstract

Unsymmetrical dioxime ligand and its mono- and multinuclear metal complexes were synthesized and characterized by H-1 and C-13 NMR spectra, FT-IR, UV-Vis, elemental analysis, melting point measurements, LC-MS spectroscopy, molar conductivity measurements and magnetic susceptibility and cyclic voltammetry techniques. We firstly prepared new unsymmetrical dioxime ligand (1) and its mononuclear [Ni(dioxime)(2)] complex (2). Then, the intramolecular O-H center dot center dot center dot O bridges are replaced with Cu(II)(N-N) complex to synthesize multinuclear [Ni(dioxime)(2)Cu-2(N-N)(2)](ClO4)(2) oxime complexes (3-7) where N-N = 2,2'-bipyridine (bpy), 1,10-phenanthroline (phen), 3,3'-dicarboxy-2,2'-bipyridine (dcbpy), 4,5-diazafluoren-9-one (dafo) and 1,10-phenanthroline-5,6-dione (dione). The mononuclear complex [Ni(dioxime)(2)] (2) was used as a precursor for building multinuclear oxime complexes (3-7). In this paper, our goal is to study spectroscopic, electrochemical and catalytic properties of this new ligand and its metal complexes. (C) 2012 Elsevier B. V. All rights reserved.