Functional metal‐porphyrazine derivatives and their polymers. VIII. Catalase‐like activity of Fe(III)‐ and Co(II)‐2,9,16,23‐tetracarboxyphthalocyanine supported on poly(2‐vinylpyridine‐CO‐styrene)

Abstract

Abstract The decomposition reaction of hydrogen peroxide by Fe(III)‐ and Co(III)‐2,9,16,23‐tetracarboxyphthalocyanine supported on poly(2‐vinylpyridine‐CO‐styrene) and the quaternized one, was studied at pH 7.0 in aqueous media. The kinetics of this reaction was also investigated at pH 7.0 by measuring the initial velocity V 0 of the increasing concentration of O 2 with a Warburg respirometer. The reaction proceeded according to the catalaselike mechanism. Fe(III)‐2,9,16,23‐tetracarboxyphthalocyanine supported on poly(2‐vinylpyridine‐CO‐styrene) was a remarkably effective catalyst for a H 2 O 2 decomposition reaction. The coordination sphere around the Fe(III)‐phthalocyanine ring was characterized by electronic and ESR spectroscopy. Fe(III)‐phthalocyanine supported on the copolymer dispersed in water was the five‐coordinated, high‐spin type. A typical competitive inhibition in respect of H 2 O 2 by CN‐ was observed. ESR spectrum of this system showed the low spin iron(III) in the octahedral ligand field. The polymer coils hindered undesirable dimerization of metal‐phthalocyanine molecules by the shielding effect.