نتایج جستجو برای: copper cu

تعداد نتایج: 128607  

2013

Copper (II) is a biologically active essential ion and it forms the active centers in several metalloenzymes and proteins. Its chelating ability and positive redox potential allow participation in biological transport reactions. The copper atom transforms between the Cu(I) and Cu(II) oxidation states in redox reactions involving copper containing enzymes. This is an essential factor for many of...

2006
M. C. Hsiao H. Paul Wang C. Y. Peng C. H. Huang Yu-Ling Wei

Speciation of copper in waste incineration fly ashes (dry scrubber (DS) and bag filter (BF)) has been studied by X-ray absorption near edge structural (XANES) spectroscopy in the present work. Copper species such as metallic Cu, CuO, Cu(OH)2, and a small amount of CuCO3 in the fly ashes could be distinguished by semi-quantitative analysis of the edge spectra. Interestingly, nano CuO (37%) were ...

Journal: :Science 2017
Junji Nakamura Tadahiro Fujitani Sebastian Kuld Stig Helveg Ib Chorkendorff Jens Sehested

Kattel et al (Reports, 24 March 2017, p. 1296) report that a zinc on copper (Zn/Cu) surface undergoes oxidation to zinc oxide/copper (ZnO/Cu) during carbon dioxide (CO2) hydrogenation to methanol and conclude that the Cu-ZnO interface is the active site for methanol synthesis. Similar experiments conducted two decades ago by Fujitani and Nakamura et al demonstrated that Zn is attached to format...

Journal: :Organic letters 2012
Zhifeng Mao Zhe Wang Zhaoqing Xu Fei Huang Zhengkun Yu Rui Wang

Cu(OAc)(2)-mediated dehydrogenative cross-coupling between two heteroarenes has been realized in the absence of any other additive. A mechanism involving a formal Cu(II) to Cu(0) route by convergent disproportionation of the copper mediator is proposed and has been evidenced by copper mirror formation during the reaction. This synthetic protocol provides a concise and "green" access to unsymmet...

Journal: :Dalton transactions 2012
Songlin Zhang Zhenzhong Zhu Yuqiang Ding

A systematic theoretical study on reaction mechanisms for copper(I)-catalyzed C-O coupling of phenols with aryl bromides is reported herein. Through evaluation of the relative concentrations of possible copper species in reaction solution and reactivity study of these copper species with aryl halides in the context of several commonly proposed mechanisms for copper(I)-catalyzed Ullmann reaction...

2007
Xiaohua Pu Xinli Zhang Zongxiao Li

The title complex, [Cu(2)(C(14)H(11)ClNO)(2)Cl(2)], has a centrosymmetric dinuclear structure where two symmetry-related copper(II) metal centres are bridged by the O atoms of two phen-oxy groups. Each copper(II) centre displays a distorted tetra-hedral coordination provided by one N atom and two O atoms from two Schiff base ligands and by one Cl atom. The Cu⋯Cu separation is 3.0702 (9) Å.

Journal: :Dalton transactions 2011
Maura Pellei Grazia Papini Andrea Trasatti Marco Giorgetti Domenica Tonelli Marco Minicucci Cristina Marzano Valentina Gandin Giuliana Aquilanti Alessandro Dolmella Carlo Santini

New nitroimidazole and glucosamine conjugated heteroscorpionate ligands, namely 2,2-bis(3,5-dimethyl-1H-pyrazol-1-yl)-N-(2-(2-methyl-5-nitro-1H-imidazol-1-yl)ethyl)acetamide (L(MN)) and 1,3,4,6-tetra-O-acetyl-2-{[bis(3,5-dimethyl-1H-pyrazol-1-yl)acetyl]amino}-2-deoxy-β-D-glucopyranose (L(DAC)), respectively, were synthesized by direct coupling of preformed side chain acid and amine components. ...

2009
Sadaaki Ekuni Jun-ichi Hirai

The possibility of alloying can not be avoided at the interface between molten brazing filler metal and base metal in brazing, so the wettability of brazing filler metal can not be easily explained theoretically. We used the original apparatus for wettability test and investigated the relation between the wettability of brazing filler metals of Ag-P-Cu and Ag-Cu-Zn-Cd systems on copper and the ...

Journal: :The Journal of chemical physics 2004
Mark S Taylor Felician Muntean W Carl Lineberger Anne B McCoy

An ab initio investigation of the potential energy surfaces and vibrational energies and wave functions of the anion, neutral, and cation Cu(H(2)O) complexes is presented. The equilibrium geometries and harmonic frequencies of the three charge states of Cu(H(2)O) are calculated at the MP2 level of theory. CCSD(T) calculations predict a vertical electron detachment energy for the anion complex o...

2014
Wu Zhong Haichuan Zhu Fugeng Sheng Yonglu Tian Jun Zhou Yingyu Chen Song Li Jian Lin

Transition metal copper (Cu) can exist in oxidized or reduced states in cells, leading to cytotoxicity in cancer cells through oxidative stress. Recently, copper complexes are emerging as a new class of anticancer compounds. Here, we report that a novel anticancer copper complex (HYF127c/Cu) induces oxidative stress-dependent cell death in cancer cells. Further, transcriptional analysis reveale...

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