Supported Copper(II) Arylhydrazone Complex on Synthesized Fe3O4 Nanoparticles Boosted with TiO2 for the Catalytic Oxidation of Alcohols

For the modified progression of organo-oxidative reactions of alcohols, a monometallic copper(II) diarylhydrazone complex (CuONLCl) was constructed through the coordination of an arylhydrazone ligand (HONL) with a copper(II) ion. Its chemical structure was validated by alternative spectroscopic approaches. The heterogeneity of CuONLCl was constructed through successful surface covering of highly paramagnetic Fe3O4/TiO2 nanoparticles (as CuONLCl@Fe3O4/TiO2). The morphological and internal structure of the CuONLCl@Fe3O4/TiO2 nanocomposite were analyzed with alternating microscopic and spectroscopic tools. The catalytic redox activity of CuONLCl (homogeneous) and CuONLCl@Fe3O4/TiO2 (heterogeneous) was examined in the selective oxidative system of alcohols, e.g., benzyl alcohol (BZA), converting it to the corresponding carbonyl derivative (benzaldehyde, BZD) using H2O2. For optimization, the temperature, time, and solvent were adjusted to establish the highest redox activity of CuONLCl and CuONLCl@Fe3O4/TiO2. The mono-oxidative product (benzaldehyde) was contaminated with the overoxidative product, benzoic acid (BZC), and other side products. The homogeneous CuONLCl catalyst adjusted its catalytic oxidative action with lower reaction time for the optimized features compared to the heterogenized CuONLCl@Fe3O4/TiO2 catalyst; however, CuONLCl@Fe3O4/TiO2 displayed more selective progress in yielding the mono-oxidative product. Both Cu-catalysts showed an amazing reusability with 3 and 7 attempts for CuONLCl and CuONLCl@Fe3O4/TiO2, respectively. The Fe3O4/TiO2 nanoparticles exhibited enhanced reusability for CuONLCl@Fe3O4/TiO2 compared to CuONCl.