Synthesis of a novel μ-acetate bridged dinuclear Cu(II) complex as model compound for the active site of tyrosinase: crystal structure, magnetic properties and catecholase activity

Reaction of the ligand N,N,N^′,N^′-bis(2-hydroxybenzyl)(N-methylimidazolyl)]-2-ol-1,3-propendiamine (Hbhbmipo) with copper(II) perchlorate and sodium acetate in acetonitrile/ethanol leads to the assembly of a novel dinuclear copper(II) complex. The crystal structure, magnetic properties and its catecholase activity are reported. Both copper(II) ions are set in a distorted square pyramidal coordination sphere with a N₂O₃ donor set resulting in a CuCu distance of 3.382(5) Å. To our knowledge this is the first example of a dinuclear Cu(II) complex with square pyramidal coordination geometry in which the N₂O₃ donor set contains N-imidazol and O-phenol. The complex represents a structural model for a tyrosine intermediate in the proposed mechanism during hydroxylation of monophenols.