Transition metal peroxo complexes relevant to metalloproteins

ABSTRACT A series of dioxygen complexes of copper, iron, and manganese have been synthesized using bulky tripodal nitrogen ligands, hydrotris(3,5-dialkyl1-pyrazolyl)borate, as models for the active sites in the metalloproteins. A binuclear copper peroxo complex having p-q2:$ coordination mode serves as an accurate model of the active site of oxy-hemocyanin. The reactivities of the complex and related peroxo copper complexes suggested a new radical type reaction mechanism for tyrosinase catalysis. Dioxygen complexes of iron are designed to provide structural and mechanical information for a non-heme oxygen carrier and monooxygenase, hemerythrin and tyrosine hydroxylase. A mononuclear dioxygen complex of manganese represents the first artificial example of hydrogen bond between the peroxide and proton in the ligand and binuclear manganese complexes do the models for the active intermediates of dioxygen evolution sites for PSII.