Synthesis Of Binuclear Copper(I) Complexes Containing Polyimidazoles And Catalytic Oxidation Of Benzoin And Exogenous Phenol With High Selectivity

The activation of molecular oxygen by metal ions is of intrinsic importance in a wide range of biological and industrial processes, relevant biological systems include tyrosinase, catechol dioxygenase, and cytochrome P-450.Studying structures and functions of metal enzymes, synthyzing their model compound, searching mimic enzyme catalysis with high efficiency and selectivity for application in organic synthesis and industrial processes are the goal people seeking. These also are important research project on bioorganic chemistry.Our works combine today's two important frontier projects in organic chemistry: high-selective organic reaction with mimic enzyme study. By effective modeling activity of Tyrosinase, the high selective ortho-oxidation would be realized a wide rang of phenols under mild conditions. This goal has not been achieved by traditional chemical method. Our study is of important research significant and application value.A large number of works indicate that imidazole is an excellent "biological ligand". The imidazole of histamine is a ubiquitous ligand, which is present in all types of copper active sites. It can serve as proton donor-acceptor, general acid-base, nucleophile and selective binding group, which play an important part whether in natural or artificial enzyme. To synthesize complexes with biologically relevant ligand still is challenging project in model approach. In very few model compoundsare imidazole or polyimdazole ligand present. Commonly, aliphatic amines and imines, or more closely related to the imidazole ring, pyridine, pyrazole and benzimidazole are used. However, it is impossible that the functions of imidazole are replaced.In view of studies in artificial enzyme, more are about dioxygen binding of model and less are about oxidation of exogenous substrate, especially high-selective ortho-oxidation in various phenols have not been realized.We here report the design, synthesis of novel polyimidazole ligands to model multihistidin. Biomimetic studies of metal complexes and catalytic behavior have been investigated. A batch of creating results has been obtained, which are of important learning significant and potential application.On the construction of biomimetic systems exhibiting tyrosinase-like activity, the traditional tyrosinase models have proven very useful. However, a major drawback of such systems is the rapid hydroxylations of the C-H bond of ligand and models hence lose catalyze activity. They are not suitable for catalytic oxidation of exogenous substrates. As a result, there has been a considerable effort to synthesize and improve model.Therefore, several speculative model compounds have been designed and possible structures of metal complexes proposed in order to fulfill specific aims. These cavities, formed by four nitrogen donor sites, should promote the binding of two copper ions, as well as mediating magnetic and electronic interactions between them. The optimum spacer group may be designed between the two-amine donors. Biimidazole are chosen as binding group and spacer.The applications of imidazole are amplified when they are incorporated in the dimeric analogue biimidazole. The nature of biimidazole is characterized by its great chemical stability and it has a near planar structure, which provides the optimum environment for enzyme mimic and selective catalysis. More importantly, biimidazole possesses bidentate chelating sites and might function as a bridging ligand. The incorporation of pendant groups provides suitable shapes and binding sites to vary the polydentate ligand. These ligands can mimic the biological unitconcerning composition, ligand type, structure and oxidation state. Biimidazole lends itself particularly well to provide a new family of multidentate ligands to bind transition metal ions.To our knowledge, binuclear copper ligends containing biimidazole have not been reported.In view of the active centers of binuclear copper protein are coordinated by polyimidazoles in natural enzyme, binuclear copper model which is coordinated by imidazoles...