High Reactivity of the ZnO(0001) Polar Surface: The Role of Oxygen Adatoms

2017 ◽  
Vol 121 (29) ◽  
pp. 15711-15718 ◽  
Author(s):  
Yang Liu ◽  
Wangping Xu ◽  
Yueyue Shan ◽  
Hu Xu
Keyword(s):  
High Reactivity ◽  
Polar Surface ◽  
Oxygen Adatoms

A first-principles study of the atomic layer deposition of ZnO on carboxyl functionalized carbon nanotubes: the role of water molecules

2021 ◽  
Vol 23 (5) ◽  
pp. 3467-3478
Author(s):  
J. I. Paez-Ornelas ◽  
H. N. Fernández-Escamilla ◽  
H. A. Borbón-Nuñez ◽  
H. Tiznado ◽  
Noboru Takeuchi ◽  
...  
Keyword(s):  
First Principles ◽  
Ligand Exchange ◽  
Functional Group ◽  
Atomic Layer ◽  
High Reactivity ◽  
Water Molecules ◽  
Exchange Reactions ◽  
Layer Deposition ◽  
The Right

Atomic description of ALD in systems that combine large surface area and high reactivity is key for selecting the right functional group to enhance the ligand-exchange reactions.

scholarly journals Characterization of the endoplasmic reticulum–resident peroxidases GPx7 and GPx8 shows the higher oxidative activity of GPx7 and its linkage to oxidative protein folding

2020 ◽  
Vol 295 (36) ◽  
pp. 12772-12785 ◽  
Author(s):  
Shingo Kanemura ◽  
Elza Firdiani Sofia ◽  
Naoya Hirai ◽  
Masaki Okumura ◽  
Hiroshi Kadokura ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Protein Folding ◽  
Physiological Role ◽  
High Reactivity ◽  
Oxidation Activity ◽  
Formation Pathway ◽  
Oxidative Protein Folding ◽  
Redox Active ◽  
Protein Disulfide

Oxidative protein folding occurs primarily in the mammalian endoplasmic reticulum, enabled by a diverse network comprising more than 20 members of the protein disulfide isomerase (PDI) family and more than five PDI oxidases. Although the canonical disulfide bond formation pathway involving Ero1α and PDI has been well-studied so far, the physiological roles of the newly identified PDI oxidases, glutathione peroxidase-7 (GPx7) and -8 (GPx8), are only poorly understood. We here demonstrated that human GPx7 has much higher reactivity with H2O2 and hence greater PDI oxidation activity than human GPx8. The high reactivity of GPx7 is due to the presence of a catalytic tetrad at the redox-active site, which stabilizes the sulfenylated species generated upon the reaction with H2O2. Although it was previously postulated that GPx7 catalysis involved a highly reactive peroxidatic cysteine that can be sulfenylated by H2O2, we revealed that a resolving cysteine instead regulates the PDI oxidation activity of GPx7. We also determined that GPx7 formed complexes preferentially with PDI and P5 in H2O2-treated cells. Altogether, these results suggest that human GPx7 functions as an H2O2-dependent PDI oxidase in cells, whereas PDI oxidation may not be the central physiological role of human GPx8.

Crosslinking Chlorosulfonated Polyethylenes

1963 ◽  
Vol 36 (4) ◽  
pp. 963-974 ◽  
Author(s):  
J. T. Maynard ◽  
P. R. Johnson
Keyword(s):  
Free Radical ◽  
Sulfonyl Chloride ◽  
High Reactivity ◽  
Good Resistance ◽  
Chlorosulfonated Polyethylene ◽  
Ionic Salt ◽  
Ionic Bonds ◽  
Resistance To Heat ◽  
Curing Systems

Abstract The broadening practical use of chlorosulfonated polyethylene elastomers for applications where good resistance to heat, oil, light, oxygen, and ozone is needed has been accelerated by the development of several chemically distinct curing systems. Optimum use of these saturated elastomers requires a knowledge of the chemistry of these curing reactions and the effect of the resulting crosslink structures on vulcanizate properties. The high reactivity of the sulfonyl chloride crosslinking sites allows wide latitude in choice of curing chemistry, and crosslink type can be controlled to give a preponderance of ionic salt bonds or to give a mixture of covalent and ionic bonds. The role of water, alcohols, sulfur accelerators and free radical stabilizers in the various practical curing systems is discussed. The development of wholly organic curing systems for chlorosulfonated polyethylenes is reviewed. The properties of vulcanizates of chlorosulfonated polyethylenes are also significantly controlled by the base polyethylene, by chlorine content, and by chlorine distribution. The effects of these variables on vulcanizate properties is briefly reviewed.

scholarly journals Correction: Control of selectivity in allylic alcohol oxidation on gold surfaces: the role of oxygen adatoms and hydroxyl species

2015 ◽  
Vol 17 (14) ◽  
pp. 9569-9569
Author(s):  
Gregory M. Mullen ◽  
Liang Zhang ◽  
Edward J. Evans ◽  
Ting Yan ◽  
Graeme Henkelman ◽  
...  
Keyword(s):  
Alcohol Oxidation ◽  
Chem Phys ◽  
Allylic Alcohol ◽  
Gold Surfaces ◽  
Oxygen Adatoms ◽  
Phys Chem Chem Phys

Correction for ‘Control of selectivity in allylic alcohol oxidation on gold surfaces: the role of oxygen adatoms and hydroxyl species’ by Gregory M. Mullen et al., Phys. Chem. Chem. Phys., 2015, 17, 4730–4738.

Structural insights into the peroxidase activity and inactivation of human peroxiredoxin 4

2011 ◽  
Vol 441 (1) ◽  
pp. 113-118 ◽  
Author(s):  
Xi Wang ◽  
Likun Wang ◽  
Xi'e Wang ◽  
Fei Sun ◽  
Chih-chen Wang
Keyword(s):  
Endoplasmic Reticulum ◽  
Structural Analysis ◽  
Conformational Changes ◽  
Active Site ◽  
High Reactivity ◽  
Structural Explanation ◽  
Disulfide Formation ◽  
Redox Forms ◽  
Structural Insights

Prx4 (peroxiredoxin 4) is the only peroxiredoxin located in the ER (endoplasmic reticulum) and a proposed scavenger for H2O2. In the present study, we solved crystal structures of human Prx4 in three different redox forms and characterized the reaction features of Prx4 with H2O2. Prx4 exhibits a toroid-shaped decamer constructed of five catalytic dimers. Structural analysis revealed conformational changes around helix α2 and the C-terminal reigon with a YF (Tyr-Phe) motif from the partner subunit, which are required for interchain disulfide formation between Cys87 and Cys208, a critical step of the catalysis. The structural explanation for the restricting role of the YF motif on the active site dynamics is provided in detail. Prx4 has a high reactivity with H2O2, but is susceptible to overoxidation and consequent inactivation by H2O2. Either deletion of the YF motif or dissociation into dimers decreased the susceptibility of Prx4 to overoxidation by increasing the flexibility of Cys87.

scholarly journals Uncovering the key role of distortion in tetrazine ligations guides the design of bioorthogonal tools with high reactivity and superior stability

2021 ◽  
Author(s):  
Dennis Svatunek ◽  
Martin Wilkovitsch ◽  
Lea Hartmann ◽  
Kendall Houk ◽  
Hannes Mikula
Keyword(s):  
High Reactivity

scholarly journals Copper-Mediated Nitrosation: 2-Nitrosophenolato Complexes and Their Use in the Synthesis of Heterocycles

Molecules ◽  
2019 ◽  
Vol 24 (22) ◽  
pp. 4154 ◽  
Author(s):  
Alexander J. Nicholls ◽  
Andrei S. Batsanov ◽  
Ian R. Baxendale
Keyword(s):  
High Reactivity ◽  
Substitution Pattern ◽  
Decomposition Products ◽  
Novel Structure ◽  
Simple Protocol ◽  
Polymer Supported

A simple protocol yielding ortho-substituted nitrosophenols from phenols is demonstrated, in the form of copper(II) bis(nitrosophenolato) complexes. The developed methodology was applied to a range of substrates, confirming the role of the copper in both the formation and protection of the challenging 1, 2-substitution pattern. Using polymer supported thiourea, the Cu could be stripped from the complexes and thus enabled the isolation or identification of the uncoordinated ligands and their decomposition products, in yields generally low in line with the intrinsic high reactivity of 2-nitrosophenols. The product complexes are useful intermediates as demonstrated in revisiting a formal [4 + 2] cycloaddition with dimethylacetylene dicarboxylate to synthesise bicyclic products in variable yields, revealing the product has a novel structure different from those previously reported in the literature.

Manipulation of Pt-Ni Tetrahexahedral Nanoframes Using a Gaseous Etching Method

MRS Advances ◽  
2018 ◽  
Vol 3 (18) ◽  
pp. 943-948 ◽  
Author(s):  
Yiliang Luan ◽  
Lihua Zhang ◽  
Chenyu Wang ◽  
Jingyue Liu ◽  
Jiye Fang
Keyword(s):  
Driving Force ◽  
Surface Defects ◽  
Catalytic Performance ◽  
High Reactivity ◽  
Etching Time ◽  
Industry Research ◽  
Catalytic Fields ◽  
Metallic Complex ◽  
Annealing Operation

ABSTRACTNanosized Platinum (Pt) nanocrystals (NCs) have been extensively investigated in catalytic fields because of their high reactivity due to the unique electron structure. However, the rarity and the high cost of Pt limit its applications in industry. To reduce the usage of Pt in catalytic industry, research interests have been extended to Pt-based nanoalloys. Among various nanostructures, nanoframes (NFs) showed promising catalytic performance even with a lower metallic loading dose. Herein, we report a facile and robust method to transfer the Pt-Ni tetrahexahedral (THH) NCs into THH NFs in which carbon monoxide (CO) plays a role of the “etching reagent”. The driving force of the etching is a formation of gaseous metallic complex, Ni(CO)4, known as Mond Process, preferentially dealloying nickel atoms along <100> directions of the Pt-Ni THH NCs. It is determined that the resultant Pt-Ni THH NFs possess an open, stable and high-index preserved nanostructure, in which the outside atomic layers are composed of only Pt atoms with surface strains. Compared to a solution-based etching process, this approach requires less etching time and generates a well-defined structure. The associated thermal annealing operation also releases extra internal stress, making the NFs more stable with fewer surface defects. Such Pt-Ni THH NFs show interesting potentials in the improvement of stability and activity as advanced catalysts.

The role of carbon atoms of supported iron carbides in Fischer–Tropsch synthesis

2015 ◽  
Vol 5 (3) ◽  
pp. 1433-1437 ◽  
Author(s):  
V. V. Ordomsky ◽  
B. Legras ◽  
K. Cheng ◽  
S. Paul ◽  
A. Y. Khodakov
Keyword(s):  
Reaction Rate ◽  
Iron Carbide ◽  
High Reactivity ◽  
Tropsch Synthesis ◽  
Chain Growth ◽  
Fischer Tropsch ◽  
Iron Carbides ◽  
Fischer Tropsch Synthesis ◽  
Supported Iron

High reactivity of iron carbides enhances the Fischer–Tropsch reaction rate on supported iron catalysts. Carbon atoms in iron carbide are involved in the initiation of chain growth in Fischer–Tropsch synthesis.

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