Development of Novel Inorganic Metal Complexes for Catalytic Applications in Green Oxidation Reactions

Abstract

Background: Growing need for nonpolluting chemical processes has led to the synthesis of new inorganic metal complexes for their application in catalysis in the green oxidation process. Transition metal complexes, in particular, with Schiff base ligands have demonstrated encouraging activity owing to their modifiable structures and redox behaviour. Aim: The objective of the present work is to prepare and characterize some metal complexes derived from Schiff bases and to test their efficiency in the green oxidative of alcohols and olefins with H₂O₂ as an oxidant. Method: Four new complexes of Fe(III), Mn(II), Cu(II), and Co(II) were prepared with some bidentate Schiff base ligands and were characterized by FTIR, UV-Vis spectra, elemental analysis, and conductance measurements. They were used as catalysts for the oxidation of benzyl alcohol to benzaldehyde as well as cyclohexene to cyclo-hexe-none. Results: Of the prepared complexes, the Fe(III) complex (FeL2) was found to be the most active, affording 91% conversion with 97.5% selectivity for benzaldehyde and 84.1% conversion with 95% selectivity for cyclo-hexe-none. The recyclability of FeL2 was proved up to 5 runs without any significant loss of catalytic activity. Conclusion: The results demonstrate the efficiency, selectivity and recyclability of FeL2 in "green" oxidation processes, underscoring the potential of this cationic Fe complex as an environmentally benign catalyst for sustainable chemical processes. These findings promote the green chemistry by providing efficient options for the traditional oxidative systems.

Keywords: Green chemistry, Schiff base, metal complexes, oxidation catalysis, hydrogen peroxide, Fe(III) catalyst, sustainable reactions.