| Autor: |
Panda S; Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States., Phan H; Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States., Dunietz EM; Department of Chemistry, Stanford University, Stanford, California 94305, United States., Brueggemeyer MT; Department of Chemistry, Stanford University, Stanford, California 94305, United States., Hota PK; Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States., Siegler MA; Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States., Jose A; Department of Chemistry, Stanford University, Stanford, California 94305, United States., Bhadra M; Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States., Solomon EI; Department of Chemistry, Stanford University, Stanford, California 94305, United States.; Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States., Karlin KD; Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States. |
| Abstrakt: |
Synthetic side-on peroxide-bound dicopper(II) ( S P ) complexes are important for understanding the active site structure/function of many copper-containing enzymes. This work highlights the formation of new {Cu II (μ-η 2 :η 2 -O 2 2- )Cu II } complexes (with electronic absorption and resonance Raman (rR) spectroscopic characterization) using tripodal N 3 ArOH ligands at -135 °C, which spontaneously participate in intramolecular phenolic H-atom abstraction (HAA). This results in the generation of bis(phenoxyl radical)bis(μ-OH)dicopper(II) intermediates, substantiated by their EPR/UV-vis/rR spectroscopic signatures and crystal structural determination of a diphenoquinone dicopper(I) complex derived from ligand para -C═C coupling. The newly observed chemistry in these ligand-Cu systems is discussed with respect to (a) our Cu-MeAN (tridentate N , N , N ', N ', N ″-pentamethyldipropylenetriamine)-derived model S P species, which was unreactive toward exogenous monophenol addition ( J . Am . Chem . Soc . 2012 , 134, 8513-8524), emphasizing the impact of intramolecularly tethered ArOH groups, and (b) recent advances in understanding the mechanism of action of the tyrosinase (Ty) enzyme. |
