Zeolite Encaged Cu(Histidine) Complexes as Mimics of Natural Cu Enzymes

摘要

The mot abundant, active, and selective catalysts in nature are enzymes. Their operational domain is. however, relatively narrow as far as temperature and solvent are concerned. Enzyme mimicking is the building of the active center of enzymes (or ananalogy of it) into a matrix which allows a larger operational temperature domain and a broader spectrum of solvents. In the case of inorganic matrices, zeolites are the obvious choice because the pore diameters and pore geometry introduce shape selectivity in the reactions. Up to now. the active center of the enzyme has been mimicked by construction of robust, rigid, and stable transition metal ion complexes in zeolite cavities and channels. The most prominent examples are phthalocyanine and bipyridinecomplexes. However, these complexes can only be synthesized in situ and this procedure is time-consuming. Moreover, the turnover numbers in catalytic oxidations are relatively low.