A stabilized mu-eta(2):eta(2) peroxodicopper(II) complex with a secondary diamine ligand and its tyrosinase-like reactivity.
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.
Mirica
Liviu M
LM
Department of Chemistry, Stanford University, California 94305, USA.
Vance
Michael
M
Rudd
Deanne Jackson
DJ
Hedman
Britt
B
Hodgson
Keith O
KO
Solomon
Edward I
EI
Stack
T D P
TD
D003300:Copper / Q000737:chemistry / Q000378:metabolism*; D003959:Diamines / Q000378:metabolism*; D008024:Ligands; D014442:Monophenol Monooxygenase / Q000378:metabolism*; D010545:Peroxides / Q000737:chemistry / Q000378:metabolism*
D003959:Diamines; D008024:Ligands; D010545:Peroxides; D003300:Copper; D014442:Monophenol Monooxygenase