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 H 2 O 2 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.