Dinuclear site structure reactivity

The goal of diiron model chemistry is to develop small molecule systems that accurately reproduce spectroscopic, structural, and more ambitiously, reactivity aspects of driron metaUoproteins. Despite being structurally similar, diiron enzymes carry out a variety of catalytic processes see Iron Proteins with Dinuclear Active Sites)Advancements in the synthesis and characterization of small molecule mimics for nonheme diiron enzymes have been tremendous in the last decade. Biomimetic studies have been carried out in efforts to reproduce the structural and functional aspects of these biocatalysts. Although this has been a challenging endeavor, much information regarding the structural and mechanistic aspects of catalytic intermediates has been obtained. 

In this chapter, the dioxygen activation mechanism at the dinuclear copper-active sites of tyrosinase and catechol oxidase has been surveyed. In both enzymes, a (ji-rfirf -peToxo) dicopper(II) complex has been detected and characterized as a common reactive intermediate by several spectroscopic methods. In spite of longstanding efforts in the enzymological studies, mechanistic details of the enzymatic reactions (phenolase and catecholase activities) still remain ambiguous. On the other hand, recent developments in the model chemistry have provided a great deal of information about the structure and physicochemical properties as well as the reactivity of the peroxo intermediate and have advanced our understanding of the enzymatic reactions. 

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