Journal ArticleDOI
X-ray absorption edge determination of the oxidation state and coordination number of copper: application to the type 3 site in Rhus vernicifera laccase and its reaction with oxygen
Lung Shan Kau,Darlene J. Spira-Solomon,James E. Penner-Hahn,Keith O. Hodgson,Edward I. Solomon +4 more
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TLDR
In this paper, a normalized difference edge analysis is used to quantitatively determine the oxidation states of the copper sites in type 2 copper-depleted (T2D) and native forms of the multicopper oxidase, Rhus vernicifera laccase.Abstract:
Cu X-ray absorption edge features of 19 Cu(I) and 40 Cu(II) model complexes have been systematically studied and correlated with oxidation state and geometry. Studies of Cu(I) model complexes with different coordination number reveal that an 8983-8984-eV peak (assigned as the Cu 1s ..-->.. 4p transition) can be correlated in energy, shape, and intensity with ligation and site geometry of the cuprous ion. These Cu(I) edge features have been qualitatively interpreted with ligand field concepts. Alternatively, no Cu(II) complex exhibits a peak below 8985.0 eV. The limited intensity observed in the 8983-8985-eV region for some Cu(II) complexes is associated with the tail of an absorption peak at approx. 8986 eV which is affected by the covalency of the equatorial ligands. These models studies allow accurate calibration of a normalized difference edge procedure which is used for the quantitative determination of Cu(I) content in copper complexes of mixed oxidation state composition. This normalized difference edge analysis is then used to quantitatively determine the oxidation states of the copper sites in type 2 copper-depleted (T2D) and native forms of the multicopper oxidase, Rhus vernicifera laccase. The type 3 site of the T2D laccase is found to be fully reduced and stable tomore » oxidation by O/sub 2/ or by 25-fold protein equivalents of ferricyanide, but it can be oxidized by reaction with peroxide. The increase in intensity of the 330-nm absorption feature which results from peroxide titration of T2D laccase is found to correlate linearly with the percent of oxidation of the binuclear copper site.« lessread more
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Hybrid Cu(x)O/TiO₂ nanocomposites as risk-reduction materials in indoor environments.
Xiaoqing Qiu,Masahiro Miyauchi,Kayano Sunada,Masafumi Minoshima,Min Liu,Yue Lu,Ding Li,Yoshiki Shimodaira,Yasuhiro Hosogi,Yasushi Kuroda,Kazuhito Hashimoto +10 more
TL;DR: The grafting of nanometer-sized Cu(x)O clusters onto TiO(2) generates an excellent risk-reduction material in indoor environments by controlling the balance between Cu(I) and Cu(II) in Cu(X)O, efficient decomposition and antipathogenic activity were achieved in the hybrid Cu( x)O/TiO( 2) nanocomposites.
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A Consistent Reaction Scheme for the Selective Catalytic Reduction of Nitrogen Oxides with Ammonia
Ton V. W. Janssens,Hanne Falsig,Lars F. Lundegaard,Peter N. R. Vennestrøm,Søren Birk Rasmussen,Poul Georg Moses,Filippo Giordanino,Elisa Borfecchia,Kirill A. Lomachenko,Carlo Lamberti,Silvia Bordiga,Anita Godiksen,Susanne Mossin,Pablo Beato +13 more
TL;DR: In this article, the standard and fast selective catalytic reduction (SCR) of NO by NH3 are described in a complete catalytic cycle that is able to produce the correct stoichiometry while allowing adsorption and desorption of stable molecules only.
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Coupling Sub-Nanometric Copper Clusters with Quasi-Amorphous Cobalt Sulfide Yields Efficient and Robust Electrocatalysts for Water Splitting Reaction
Yipu Liu,Qiuju Li,Rui Si,Guo-Dong Li,Wang Li,Dapeng Liu,Dejun Wang,Dejun Wang,Lei Sun,Yu Zhang,Xiaoxin Zou +10 more
TL;DR: Superefficient water-splitting materials comprising sub-nanometric copper clusters and quasi-amorphous cobalt sulfide supported on copper foam give a catalytic output of overall water splitting comparable with the Pt/C-IrO2 -coupled electrolyzer.
Journal ArticleDOI
Imaging of the intracellular topography of copper with a fluorescent sensor and by synchrotron x-ray fluorescence microscopy
Liuchun Yang,Reagan McRae,Maged Henary,Raxit Patel,Barry Lai,Stefan Vogt,Christoph J. Fahrni +6 more
TL;DR: The presented data provide a coherent picture with strong evidence for a kinetically labile copper pool, which is predominantly localized in the mitochondria and the Golgi apparatus.
Journal ArticleDOI
XAFS, IR, and UV−Vis Study of the CuI Environment in CuI-ZSM-5
Carlo Lamberti,Silvia Bordiga,M. Salvalaggio,Giuseppe Spoto,Adriano Zecchina,Francesco Geobaldo,G. Vlaic,M. Bellatreccia +7 more
TL;DR: XAFS, IR, and UV−vis spectroscopies have been employed to investigate the local environment of CuI in CuI-ZSM-5 prepared by gas phase reaction of ZSM with CuCl.
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