Synthesis of novel Schiff base metal complexes with reactive groups and their catalytic property for hydrogen peroxide decomposition

Abstract

A novel water soluble azo Schiff base ligand containing crosslinking reactive groups (A), 3,5-bis [(2-hydroxy-4′-sodiumsulphatoethylsulphonyl) azobenzene- methyneimino]-benzoic acid (BHSABA), and its complexes with Mn²⁺, Cu²⁺, Co²⁺, were synthesized and characterized by elemental analysis, Fourier transform infrared (FT-IR) and proton nuclear magnetic resonance (¹HNMR) spectroscopy. The Schiff base ligand and its complexes had excellent water solubility. Two reactive groups, p-[(2′-sulphatoethyl) sulphonyl groups, were able to form covalent bonds with biomass, such as cellulose, chitosan and so on, to obtain functional material. Ultraviolet–visible (UV-vis) electronic absorbance and fluorescence spectra of the ligand having azo conjugated system and of the metal complexes were measured. The catalytic activity of the ligand and the complexes for H₂O₂ decomposition were also investigated. The results show that the fluorescence spectra of the complexes, Co₂A and Mn₂A, had increased fluorescence phenomena. They had strong catalytic activity for H₂O₂ decomposition. When the concentration of manganese complex, Mn₂A, was 5 mg/l, H₂O₂ decomposition nearly finished in 40 min at 40℃. The order of catalytic activity of three complexes for H₂O₂ decomposition was Mn₂A > Co₂A > Cu₂A. The ligand itself had no noticeable catalytic activity for H₂O₂ decomposition. These novel water soluble Schiff base metal complexes with reactive groups have potential application in the H₂O₂ decomposition of water treatment fields.