These composites were obtained at DAB:Cu ratios 0.25 and 0.5, respectively. Formation of CuCl can be explained by an insufficient quantity of the organic ligand for the reduction of Cu II to metallic Cu in these two cases. In the case of Cu@SiO2-11, DAB:Cu ratio was 0.65 and reflexes of CuCl were not observed on XRD pattern, so the amount of ligand at this level was sufficient for the complete reduction of Cu II . For other composites obtained from CuCl2 no reflections of CuCl were found in the diffraction patterns. The composite Cu@SiO2-18 was prepared with DAB:Cu ratio equal to 2 and the absence of CuCl in this composite was confirmed by the XRD and EDX methods. Thus, in the case of pyrolysis of samples obtained from the reaction mixtures with ligand:Cu ratio ≥ 0.65, Cu II was completely reduced and chlorine was removed.