Preparation, Characterization, and Oxidation Catalysis of Polymer-Supported Ruthenium and Cobalt Complexes

The polymer-anchored Schiff base ligand was prepared by reacting chloromethylated poly(styrene-divinyl-benzene) with 5% crosslinking with 4-hydroxybenzaldehyde, followed by condensing with 2-aminopyridine, then loading of ruthenium(III) and cobalt(II) ions in methanol. The loading of metal is 0.7%−0.8%. The polymer-supported Ru and Co complexes were characterized by different techniques, such as Fourier transform infrared (FTIR) and reflectance ultraviolet−visible light (UV−vis) spectroscopy. Thermogravimetric analysis (TGA) revealed the thermal stability of the catalysts. The catalytic activity of the polymer-supported metal catalysts was tested for oxidation of alcohols (1-phenylethanol, cyclohexanol, and benzyl alcohol) and ethylbenzene. The use of tert-butyl hydroperoxide (t-BuOOH) as an oxidant resulted in higher product yield, in comparison to using H2O2 and iodosylbenzene under the same reaction conditions. The solvent, reaction time, and amount of catalyst influenced the catalyst activity and selectivity. The oxidations performed without solvent at 70 °C show high activity. The catalytic activity of the Ru catalyst is greater than that of the Co catalyst.