Functional metallomacrocycles and their polymers. Part 31. Autoxidation of thiol by temperature-sensitive polymer catalyst containing cobalt(II) phthalocyanine complex

Abstract

Copolymers (I-IV) of 2-acryloylamino-9,16,23-tri(t-butyl)phthalocyanine (APc(t-Bu)₃) and acrylamide derivatives were prepared and their catalytic activity for oxidation of 2-mercaptoethanol was examined. Copolymers (II and IV) of APc(t-Bu)₃ and N-isopropylacrylamide revealed a lower critical solution temperature phenomenon at 29°C in carbonate buffer, that is to say, the copolymers dissolving in buffer solution below 29°C separated out as precipitate above 29°C. The catalytic activity of polymer IV, which was prepared by metalation of copolymer II, markedly changed around 29°C. Copolymer IV served as a homogeneous catalyst of autoxidation of 2-mercaptoethanol below 29°C. In contrast, the catalytic activity drastically decreased above 29°C because of separation as precipitate.