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
Reads0
Chats0
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
Citations
More filters
Journal ArticleDOI
Reversible dual-ion battery via mesoporous Cu2O cathode in SO2-in-salt non-flammable electrolyte
Kyung Hwan Kwak,Hyun Jung Suh,Ayoung Kim,Sanghyuk Park,Juhye Song,Siying Li,Youngkwon Kim,Goojin Jeong,Hansu Kim,Young-Jun Kim +9 more
TL;DR: In this paper, the authors proposed a strategy to configure dual-ion storage battery based on SO2 solvated chloroaluminate molten salt complex electrolyte employing Cu2O cathode material.
Journal ArticleDOI
SEM and XAS characterization at beginning of life of Pd-based cathode electrocatalysts in PEM fuel cells.
Karina Suárez-Alcántara,Karina Suárez-Alcántara,D.C. Martínez-Casillas,Kaibo Zheng,Qiushi Zhu,Mohamed Abdellah,Mohamed Abdellah,Dörthe Haase,Tõnu Pullerits,Omar Solorza-Feria,Sophie E. Canton +10 more
TL;DR: In this article, the fuel cell performance of membrane electrode assemblies with a Pt anode and Pd, PdCu or Pd5Cu4Pt cathodes has been tested during 116 h (beginning of life).
Journal ArticleDOI
Identification of copper(II) binding sites in the aminoglycosidic antibiotic Neomycin B
Małgorzata Jeżowska-Bojczuk,Wojciech Szczepanik,Wojciech Szczepanik,Stefano Mangani,Elena Gaggelli,Nicola Gaggelli,Gianni Valensin +6 more
TL;DR: In this article, the copper-II coordination properties of neomycin B were studied in solution by potentiometry, NMR, UV/Vis, CD, and EPR spectroscopy, XAS and mass spectrometry.
Journal ArticleDOI
Reversible and Fast (De)fluorination of High-Capacity Cu2O Cathode: One Step Toward Practically Applicable All-Solid-State Fluoride-Ion Battery
Datong Zhang,Kentaro Yamamoto,Yanchang Wang,Shenghan Gao,Tomoki Uchiyama,Toshiki Watanabe,Tsuyoshi Takami,Toshiyuki Matsunaga,Koji Nakanishi,Hidenori Miki,Hideki Iba,Koji Amezawa,Kazuhiko Maeda,Hiroshi Kageyama,Yoshiharu Uchimoto +14 more
Journal ArticleDOI
Catalytic direct oxidation of methane to methanol by redox of copper mordenite
Junya Ohyama,Airi Hirayama,Yuka Tsuchimura,Nahoko Kondou,Hiroshi Yoshida,Masato Machida,Shun Nishimura,Kazuo Kato,Itsuki Miyazato,Keisuke Takahashi +9 more
TL;DR: In this article, the catalytic production of CH3OH by direct oxidation of CH4 with O2 was performed using Cu zeolite catalysts in a CH4/O2/H2O flow reaction.
Related Papers (5)
ATHENA, ARTEMIS, HEPHAESTUS: data analysis for X-ray absorption spectroscopy using IFEFFIT.
Bruce Ravel,Matthew Newville +1 more