Peroxides metal coordinating polymers

Polymer-metal complexes often exhibit high efficiency in the catalytic decomposition of hydrogen peroxide. The following reasons for this activity have been advanced, (i) Some polymer-metal complexes contain incomplete complexes due to steric hindrance, and this contributes to their catalytic activity121, 122. (ii) In other polymer complexes, the coordinate bond between polymer ligand and metal ion is relatively weak and the substrate coordinates with high frequency124. ... 

This chapter presents various examples of enzyme catalysis by polymers including ester hydrolysis, decomposition of hydrogen peroxide, oxidation of disubstituted phenols and hydroquinone, interfacial catalysis and other types of reaction. Because metal ions (Fe, Zn, Cu. Mn, Co, etc.) are often involved as coferments during enzyme catalysis, some examples illustrating their catalytic action are also given. The catalytic activity of polymeric coordination compounds is shown to depend on the strength of the ligand-metal bond. 

The first chapter of the book deals with enzyme-like eatalysis by synthetic polymers - catalysis by polymeric acids and bases, amphoteric polyelectrolytes and nonionic polymers. Because coordination compounds of metal ions with macromolecular ligands are interesting with regard to bioinorganic chemistry, this book elucidates some problems involving the catalysis by water-soluble polymer-metal complexes. Ester hydrolysis, hydrogen peroxide decomposition, oxidation of disubstituted phenols, hydroquinones, mercaptoalcohols and other types of reaction are chosen as model processes. A section devoted to interfacial catalysis is also included. 

Two different catalysts for hydrogen peroxide decomposition, the enzyme peroxidase (isolated from the horseradish root, HRP), and polymer-supported catalyst (acid form of poly-4-vinylpyri-dine functionalized by ferric sulfate, apFe) [99,100], are examined with an aim to compare their activity. The active center in the peroxidases is the ferric ion in protoporphyrin IX. Besides the complex made of ferric ion and protoporphyrin IX, that is ferricprotoporphyrin IX, also known as ferric heme or hemin, peroxidase possesses a long chain of proteins [101,102]. On the other hand, the macroporous acid form of polyvinyl pyridine functionalized by ferricsulfate is obtained from cross-linked polyvinyl pyridine in macroporous bead form [103]. Pyridine enables it to form coordination complexes or quaternary salts with different metal ions such as iron (111) [104]. An active center on the polymeric matrix functionalized by iron, as metallic catalyst immobilized on polymer by pyridine, has similar microenvironment conditions as active center in an enzyme [105]. 

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