排序方式: 共有10条查询结果,搜索用时 15 毫秒
1
1.
A Molecular Approach to Self‐Supported Cobalt‐Substituted ZnO Materials as Remarkably Stable Electrocatalysts for Water Oxidation
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Johannes Pfrommer Dr. Michael Lublow Anahita Azarpira Dr. Caren Göbel Marcel Lücke Dr. Alexander Steigert Martin Pogrzeba Dr. Prashanth W. Menezes Dr. Anna Fischer Dr. Thomas Schedel‐Niedrig Prof. Dr. Matthias Driess 《Angewandte Chemie (International ed. in English)》2014,53(20):5183-5187
In regard to earth‐abundant cobalt water oxidation catalysts, very recent findings show the reorganization of the materials to amorphous active phases under catalytic conditions. To further understand this concept, a unique cobalt‐substituted crystalline zinc oxide (Co:ZnO) precatalyst has been synthesized by low‐temperature solvolysis of molecular heterobimetallic Co4?xZnxO4 (x=1–3) precursors in benzylamine. Its electrophoretic deposition onto fluorinated tin oxide electrodes leads after oxidative conditioning to an amorphous self‐supported water‐oxidation electrocatalyst, which was observed by HR‐TEM on FIB lamellas of the EPD layers. The Co‐rich hydroxide‐oxidic electrocatalyst performs at very low overpotentials (512 mV at pH 7; 330 mV at pH 12), while chronoamperometry shows a stable catalytic current over several hours. 相似文献
2.
We have determined the hydrogen-bond geometry in liquid water from 0 to 80 degrees C by combining measurements of the proton magnetic shielding tensor with ab initio density functional calculations. The resulting moments of the distributions of hydrogen-bond length and angle are direct measures of thermal disorder in the hydrogen-bond network. These moments, and the distribution functions that can be reconstructed from them, impose quantitative constraints on structural models of liquid water. 相似文献
3.
Greg BG Moorhead Laura Trinkle-Mulcahy Mhairi Nimick Veerle De Wever David G Campbell Robert Gourlay Yun Wah Lam Angus I Lamond 《BMC biochemistry》2008,9(1):28
Background
Protein phosphatase one (PP1) is a ubiquitously expressed, highly conserved protein phosphatase that dephosphorylates target protein serine and threonine residues. PP1 is localized to its site of action by interacting with targeting or regulatory proteins, a majority of which contains a primary docking site referred to as the RVXF/W motif. 相似文献4.
Young-Gui Yoon Bernd G. Pfrommer Steven G. Louie Andrew Canning 《Solid State Communications》2004,131(1):15-19
We present calculations of NMR chemical shifts in crystalline phases of some representative amino acids such as glycine, alanine, and alanyl-alanine. We explore the effects of environment on the chemical shifts in selected glycine geometries ranging from the crystalline phase to completely isolated molecules. In the crystalline and dilute molecular limits, the calculated distinct NMR chemical shifts are attributed to intermolecular hydrogen-bonds and dipole electric field effects, respectively. 相似文献
5.
6.
alpha-Keto alkynes react with CO and H(2) in the presence of catalytic quantities of the zwitterionic rhodium complex (eta(6)-C(6)H(5)BPh(3))(-)Rh(+)(1,5-COD) and triphenyl phosphite affording either the 2-, 2(3H)-, or 2(5H)-furanones in 61-93% yields. The cyclohydrocarbonylation is readily accomplished using substrates containing alkyl, aryl, vinyl, and alkoxy groups at the acetylenic terminal, as well as a variety of primary, secondary, and tertiary alkyl, aryl, and heteroaryl groups connected to the ketone functionality. Structural and electronic properties present in the starting materials mediate the chemo- and regioselectivity of the reaction. 相似文献
7.
Nicole Kroll Ina Speckmann Marc Schoknecht Jana Gülzow Marek Diekmann Johannes Pfrommer Anika Stritt Maria Schlangen Andreas Grohmann Gerald Hrner 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(38):13606-13612
Formation of the O?O bond is considered the critical step in oxidative water cleavage to produce dioxygen. High‐valent metal complexes with terminal oxo (oxido) ligands are commonly regarded as instrumental for oxygen evolution, but direct experimental evidence is lacking. Herein, we describe the formation of the O?O bond in solution, from non‐heme, N5‐coordinate oxoiron(IV) species. Oxygen evolution from oxoiron(IV) is instantaneous once meta‐chloroperbenzoic acid is administered in excess. Oxygen‐isotope labeling reveals two sources of dioxygen, pointing to mechanistic branching between HAT (hydrogen atom transfer)‐initiated free‐radical pathways of the peroxides, which are typical of catalase‐like reactivity, and iron‐borne O?O coupling, which is unprecedented for non‐heme/peroxide systems. Interpretation in terms of [FeIV(O)] and [FeV(O)] being the resting and active principles of the O?O coupling, respectively, concurs with fundamental mechanistic ideas of (electro‐) chemical O?O coupling in water oxidation catalysis (WOC), indicating that central mechanistic motifs of WOC can be mimicked in a catalase/peroxidase setting. 相似文献
8.
9.
Peter Döhlert Johannes Pfrommer 《Phosphorus, sulfur, and silicon and the related elements》2016,191(9):1189-1193
A straightforward protocol for the depolymerization of end-of-life poly(dimethylsilazane) using boron trifluoride diethyl etherate as depolymerization reagent to convert the Si-N to Si-F bonds was set-up. The application of the depolymerization reagent affords difluorodimethylsilane as major products, which can be a suitable synthon for the synthesis of new polymers (e.g., poly(dimethylsiloxanes) and allow an overall recycling of the [Me2Si]-unit. 相似文献
10.
1