Copper complexes as biomimetic models of catechol oxidase: mechanistic studies

The research described in this thesis deals with the synthesis of copper(II) complexes with phenol-based or macrocyclic ligands, which can be regarded as model compounds of the active site of catechol oxidase, and with the mechanism of the catalytic oxidation of catechol mediated by these compounds. Catechol oxidase is a type-3 copper enzyme usually encountered in plants and in some crustaceans, which catalyzes a conversion of a wide range of o-diphenols (catechols) to the respective o-benzoquinones. These highly reactive compounds subsequently auto-polymerize, resulting in the formation of a dark pigment melanin, which is thought to protect a damaged tissue from pathogens. In the thesis, the structural and physicochemical properties of the obtained copper complexes are discussed. The kinetic studies on the catalytic oxidation of model substrates, e.g. 3,5-ditert-butylcatechol and tetrachlorocatechol, by these complexes and the catalytic oxidation mechanism are further reported.