Experimental data have been obtained to evaluate the catalytic activity of copper chelate Cu(NOaEuro cent)(2) with the paramagnetic ligand in the degradation reactions of hydroperoxide and diacyl peroxide in the aprotic solvent chlorobenzene or in ethyl alcohol, which is capable of forming intermolecular hydrogen bonds. The presence of paramagnetic centers in the ligand have an insignificant effect on the catalytic activity of the copper chelate in the reaction with tetralyl hydroperoxide and benzoyl peroxide in chlorobenzene as compared to another compound CuL2, which have no paramagnetic centers in the ligand. The catalytic activity of Cu(NOaEuro cent)(2) has been found to increase during the reaction with benzoyl peroxide in chlorobenzene, in contrast to CuL2, which is completely deactivated in this reaction. The EPR spectra of the chelate Cu(NOaEuro cent)(2) exhibit a signal due to the nitroxide radical alone. The signal of the central Cu atom is not observed; i.e., there is the case of EPR-undetectable copper in this coordination compound.