The multinuclear cobaloxime complexes-based catalysts for direct synthesis of cyclic carbonate from of epichlorohydrin using carbon dioxide: Synthesis and characterization

The novel examples of dicobaloxime [(dmgH)(2)ClCo-(4,40-bpy)-CoCl(dmgH)(2)] (1), organodicobaloxime [(dmgH)(2)PhCH2Co-(4,40-bpy)-CoCH2Ph(dmgH)(2)] (2), and the intramolecular hydrogen (O-H center dot center dot center dot O) bridges were replaced Cu(II) containing multinuclear cobaloxime complexes [{dmgCu(NAN)}(2)ClCo-(4,40-bpy)CoCl{ dmgCu(N-N)}(2)](ClO4)(4) (3-9) were synthesized, characterized and used in direct synthesis cyclic carbonates from carbon dioxide and various epoxides. The dicobaloxime complex (1) was used as precursors for building the intramolecular hydrogen (O-H center dot center dot center dot O) bridges replaced Cu(II) ions containing complexes (3-9). All of compounds have been characterized by H-1 and C-13 NMR spectra, FT-IR spectra, UV-Vis spectra, elemental analysis, melting point measurements, LC-MS spectra, molar conductivity measurements, and magnetic susceptibility techniques. Among the nine metal complexes, complex (2) (bearing cobalt-carbon bound) displayed the higher catalytic efficient than other complexes (1 and 3-9) under the same catalytic conditions. The intramolecular hydrogen (O-H center dot center dot center dot O) bridges were replaced Cu(II) containing complexes (3-9) that bear the dimethyl glyoximate ligands and linked ligands exhibited much lower catalytic efficiencies as compared with complexes (1) and (2). (C) 2013 Elsevier B. V. All rights reserved.