Copper (II) Complexes: Synthesis, Characterization and Catalytic Performance in the Reduction of 4-nitrophenol

Abstract

The unique characteristic of the copper (II) complexes renders many of their complexes suited for various catalysis reactions. In this study, four copper (II) complexes namely copper (II) sulphate pentahydrate (Cu-L1), tetraamminecopper (II) sulphate (Cu-L2), bis-ethylenediaminecopper (II) sulphate (Cu-L3) and copper (II) acetylacetonate (Cu-L4) were successfully synthesized and characterized by using Fourier Transform Infrared Spectroscopy and UV-Vis Spectroscopy. All complexes were synthesized by direct chemical reaction of starting material with corresponding ligand solution (sulphuric acid, ammonia solution, ethylenediamine solution and acetylacetone). These ligand solutions have been chosen in order to study the chelate effect between monodentate and bidentate ligands. Ligand solution was added in excess to obtained a more complete reaction and prevent localize supersaturation from occur. Cu-L1 acts as one of the catalyst in the reduction reaction of 4-nitrophenol (4-NP) and also being used as precursor to synthesis Cu-L2 and Cu-L3 and copper oxide nanoparticles (CuO-NPs). CuO-NPs were synthesized in a simple, efficient, and cheap method via solid state thermal decomposition. The synthesized complexes were used as catalyst in the reduction of 4-nitrophenol to 4-aminophenol in aqueous phase in the presence of sodium borohydride (NaBH4). In this work, all the complexes show great performance on catalytic activity with (90.-97.3) % of percentage conversion. The reaction time for the reduction of 4-nitrophenol was between 18-34 min for each different complex.