title: A stabilized mu-eta(2):eta(2) peroxodicopper(II) complex with a secondary diamine ligand and its tyrosinase-like reactivity.
abstract: The activation of dioxygen (O(2)) by Cu(I) complexes is an ubiquitous process in biology and industrial applications. In tyrosinase, a binuclear copper enzyme, a mu-eta(2):eta(2)-peroxodicopper(II) species is generally accepted to be the active oxidant. Reported here is the characterization and reactivity of a stable mu-eta(2):eta(2)-peroxodicopper(II) complex at -80 degrees C using a secondary diamine ligand, N,N'-di-tert-butyl-ethylenediamine (DBED). The spectroscopic characteristics of this complex (UV-vis, resonance Raman) prove to be strongly dependent on the counteranion employed and not on the solvent, suggesting an intimate interaction of the counteranions with the Cu-O(2) cores. This interaction is also supported by solution EXAFS data. This new complex exhibits hydroxylation reactivity by converting phenolates to catechols, proving to be a functional model of tyrosinase. Additional interest in this Cu/O(2) species results from the use of Cu(I)-DBED as a polymerization catalyst of phenols to polyphenylene oxide (PPO) with O(2) as the terminal oxidant.
authors.affiliation: Department of Chemistry, Stanford University, California 94305, USA.
authors.forename: Liviu M
authors.initials: LM
authors.lastname: Mirica
authors.forename: Michael
authors.initials: M
authors.lastname: Vance
authors.forename: Deanne Jackson
authors.initials: DJ
authors.lastname: Rudd
authors.forename: Britt
authors.initials: B
authors.lastname: Hedman
authors.forename: Keith O
authors.initials: KO
authors.lastname: Hodgson
authors.forename: Edward I
authors.initials: EI
authors.lastname: Solomon
authors.forename: T D P
authors.initials: TD
authors.lastname: Stack
mesh_terms: D003300:Copper / Q000737:chemistry / Q000378:metabolism*; D003959:Diamines / Q000378:metabolism*; D008024:Ligands; D014442:Monophenol Monooxygenase / Q000378:metabolism*; D010545:Peroxides / Q000737:chemistry / Q000378:metabolism*
chemical_list: D003959:Diamines; D008024:Ligands; D010545:Peroxides; D003300:Copper; D014442:Monophenol Monooxygenase