STUDIES OF COPPER-COMPLEXES DISPLAYING N3S COORDINATION AS MODELS FORCU-B CENTER OF DOPAMINE-BETA-HYDROXYLASE AND PEPTIDYLGLYCINE ALPHA-HYDROXYLATING MONOOXYGENASE

We describe the studies of new copper complexes [MeSPY2]CuPF6, 2, and [MeSPY2]Cu(ClO4)(2). CH3CN, 3, as models fur the Cu-B center of dopami ne beta-hydroxylase and peptidylglycine alpha-hydroxylating monooxygen ase. The structure of [MeSPY2]Cu(ClO4)(2). CH3CN, 3, has been establis hed by X-ray crystallography. The copper coordination exhibits a squar e pyramidal geometry where the equatorial plane is occupied by the SCl H3 group and three nitrogen atoms (tertiary amine, one pyridine, and a cetonitrile solvent), whereas the axial position binds the second pyri dine. Using FEFF calculations and multiscattering interaction, EXAFS r efinements show that the SMe group lies in the coordination sphere of copper complexes [MeSPY2]CuPF6, 2, and [MeSPY2]Cu(ClO4)(2). CH3CN, 3. While [MeSPY2]CuPF6, 2, reacts with dioxygen in dichloromethane withou t oxidation of the ligand, we observed an oxidation of the sulfide lig and when [MeSPY2]Cu(ClO4)(2). CH3CN, 3, reacts with hydrogen peroxide in methanol. Considering results, we propose that Met(314), crucial fo r DBH and PHM activity, could be the site of the H2O2 (or ascorbate) i nactivation by oxidation to the sulfoxide group.