Multinuclear Cu(II) Schiff Base Complex as Efficient Catalyst for the Chemical Coupling of CO2 and Epoxides: Synthesis, X-ray Structural Characterization and Catalytic Activity

Abstract

The synthesis, X-ray structure, spectroscopic and catalytic properties of sterically hindered Schiff-base ligands (L 1 H = N-[allylamine]-3,5-di-tert-butyl salicylaldimine, L 2 H=N-[2-amino-5-methyl pyridine]-3,5-di-tert-butyl salicylaldimine and L 3 H=N-[2-amino-6-methyl pyridine]-3,5-di-tert-butyl salicylaldimine), and their mononuclear Cu(II) complex for L 1 H with multinuclear Cu(II) complexes for L 2 H and L 3 H, were described. The copper(II) complexes of these ligands were synthesized by treating an methanolic solution of the appropriate ligand with an appropriate amount of CuCl 2 Á2H 2 O. The ligands and their copper(II) complexes were characterized by FT-IR, UV-Vis, 1 H-NMR, elemental analysis, measurement of room temperature magnetic moment, and X-ray structural determination. The reaction of the L 2 H and L 3 H ligands in a 1:1 mol ratio with CuCl 2

Brønsted Acidic Ionic Liquids Mediated Metallic Salts Catalytic System for the Chemical Fixation of Carbon Dioxide to Form Cyclic Carbonates

“…Such examples include alkali metal salts [10,11], metal oxides [12], Schiff bases [13,14], transition metal complexes [15][16][17][18][19], ion-exchange resins [20], quaternary ammonium and phosphonium salts [21][22][23][24][25][26], gold nanoparticles supported on resins [27], cross-linked polymeric nanoparticles [28] and ionic liquids [29][30][31][32][33][34][35][36][37]. Although the insertion of CO 2 into epoxides to produce five-membered carbonates has been studied extensively, there is still constant motivation for developing efficient catalysts for the chemical fixation of CO 2 .…”

Chemical fixation of CO2into cyclic carbonates by azo-containing Schiff base metal complexes

“…For this purpose, organic bases (DMAP (4-55 (dimethylamino)pyridine), CH 3 CN (acetonitrile), C 5 H 5 N (pyridine), NEt 3 (triethylamine) and PPh 3 (triphenylphosphine)) were used as co-catalyst. Interestingly, the use of CH 3 CN resulted in the yield of 1.3%, and the yield remarkably increased up to 62.1% when DMAP was used as the base in high selectivity 37 . 60 Pyridine based co-catalyst systems (C 5 H 5 N and DMAP) were found to be effective bases.…”

Homogenous Dual-Ligand Zinc Complex Catalysts for Chemical Fixation of CO2 to Propylene Carbonate

“…The homogeneous catalysts [11][12][13][14][15][16][17][18][19][20][21][22][23][24] include salen, porphyrin, phthalocyanine and other complexes of the main group and transition metals (Zn, Al, Cr, Co, Cu, Ni and Sn), as well as quaternary ammonium salts, ionic liquids and polyoxometalates. However, these usually suffer from drawbacks such as low catalytic activity/ selectivity, high temperature and pressure, water sensitivity and importantly for industrial application the corrosion of the catalyst to the reactor materials is so serious.…”