Copper-phthalocyanine coordination polymer as a reusable catechol oxidase biomimetic catalyst

Abstract

The development of selective, efficient, and recoverable/reusable catalysts for oxidation reactions has become one of the main challenges of modern chemistry. Considering our interest in efficient catalytic systems based on porphyrin (Por) and phthalocyanine (Pc) coordination polymers, we report here the synthesis, characterization and catalytic activity of a new Pc coordination polymer (coined hereafter as Cu₄CuPcSPy). The new Pc material was obtained in excellent yield, from the reaction of H₂PcSPy with an excess amount of copper(II) acetate. The catalytic efficiency of Cu₄CuPcSPy was evaluated in the oxidation of 3,5-di-tert-butylcatechol (3,5-DTBC) in the presence of molecular oxygen from air, with or without the addition of aqueous 30% hydrogen peroxide. The comparison between the homogeneous (CuPcSPy) and the heterogeneous (Cu₄CuPcSPy) catalytic systems showed a better performance for the Cu₄CuPcSPy material, that can be recovered by filtration and reused, maintaining its activity roughly unchanged during three catalytic cycles. An increment of approximately 30% was also verified in the catalytic activity of the homogeneous and heterogeneous systems by adding aqueous hydrogen peroxide to the catalytic reactions.