Syntheses of new chelate‐polymers and its catalytic activities

Some new polymeric ligands of β‐diketone type were synthesized and the catalytic effects of their copper chelates on the decomposition reaction of hydrogen peroxide and the oxidation reaction of ascorbic acid were measured in comparing with that of monomeric chelates of the same structure. The two polymeric ligands described as the following formulae (I) and (II) with thousands of molecular weight were prepared by the reaction of dimethyl‐terephthalate, bisacetyl derivatives and sodium dispersion. magnified image In the chelation reactions between the polymeric ligands and cupric ion, two reaction methods, i.e. homogeneous and interfacial, were compared in regard to the extent of the chelation. In the homogeneous reaction by using tetrahydrofuran as a reaction medium the extent of the chelation could not be over 50% of the theoretical value. On the other hand, the chelate formation was carried out quantitatively at the interface between benzyl alcohol solution of the ligands and aqueous solution of cupric salt. In the measurements of the catalytic activity of the copper chelates for the decomposition reaction of hydrogen peroxide, it was found that the catalytic activity is in the decreasing order of: The same results were observed for the oxidation reaction of ascorbic acid. On the basis of structural analyses, the catalytic activity of the chelates was assumed to depend on the bond strength between the ligand and cupric ion.