Effect of Solvation on Ozonolysis Reaction Intermediates and Transition States

2000 ◽  
Vol 6 (12) ◽  
pp. 608-617 ◽  
Author(s):  
Cenk Selçuki ◽  
Viktorya Aviyente ◽  
Philippe Aplincourt ◽  
Manuel Felipe Ruiz-López
Keyword(s):  
Transition States ◽  
Reaction Intermediates

The Role of the Substituent Pattern in Determining Selectivity in the Preparation of Tricarbonyl(η5-cyclohexadienyl)iron(1+) Salts by Acid-Catalyzed Demethoxylation

1992 ◽  
Vol 45 (1) ◽  
pp. 121 ◽  
Author(s):  
GR Stephenson ◽  
DA Owen ◽  
H Finch ◽  
S Swanson
Keyword(s):  
Transition States ◽  
Kinetic Control ◽  
Reaction Intermediates ◽  
Acid Catalyzed

The factors that determine the selectivity of the acid-catalysed dealkoxylation of unsymmetrically substituted tricarbonyl(η4-alkoxycyclohexa-1,3-diene)iron(0) complexes have been investigated. Regioselective demethoxylation of complexes with a variety of substitution patterns has indicated that the selectivity arises from differences in the stabilization of the reaction intermediates and transition states by the diene substituents on the π-bound ligand. The observed regioisomers correspond to the product of the most stabilized intermediate pathway, rather than the product of minimum rearrangement. The reactions have been shown to proceed under kinetic control.

Mechanistic insights of selective syngas conversion over Zn grafted on ZSM-5 zeolite

2020 ◽  
Vol 10 (24) ◽  
pp. 8173-8181
Author(s):  
Wei Chen ◽  
Dinesh Acharya ◽  
Zhiqiang Liu ◽  
Xianfeng Yi ◽  
Yao Xiao ◽  
...  
Keyword(s):  
Transition States ◽  
Reaction Pathways ◽  
Reaction Intermediates ◽  
Syngas Conversion ◽  
Zeolite P

On the basis of syngas conversion mechanism over Zn2+-ion exchanged ZSM-5 zeolite, the reaction pathways, reaction intermediates and transition states were determined clearly.

Analyzing reactions of single mechanoenzyme molecules by light microscopy

1992 ◽  
Vol 50 (1) ◽  
pp. 426-427
Author(s):  
Jeff Gelles
Keyword(s):  
Image Processing ◽  
Reaction Mechanisms ◽  
Transient State ◽  
Nanometer Scale ◽  
Reaction Intermediates ◽  
Enzyme Molecule ◽  
Directed Movement ◽  
Enzyme Molecules ◽  
Individual Enzyme ◽  
Single Reaction

Mechanoenzymes are enzymes which use a chemical reaction to power directed movement along biological polymer. Such enzymes include the cytoskeletal motors (e.g., myosins, dyneins, and kinesins) as well as nucleic acid polymerases and helicases. A single catalytic turnover of a mechanoenzyme moves the enzyme molecule along the polymer a distance on the order of 10−9 m We have developed light microscope and digital image processing methods to detect and measure nanometer-scale motions driven by single mechanoenzyme molecules. These techniques enable one to monitor the occurrence of single reaction steps and to measure the lifetimes of reaction intermediates in individual enzyme molecules. This information can be used to elucidate reaction mechanisms and determine microscopic rate constants. Such an approach circumvents difficulties encountered in the use of traditional transient-state kinetics techniques to examine mechanoenzyme reaction mechanisms.

Lateral Adsorbate Interactions Inhibit HCOO- While Promoting CO Selectivity for CO2 Electrocatalysis on Ag

2018 ◽  
Author(s):  
Divya Bohra ◽  
Isis Ledezma-Yanez ◽  
Guanna Li ◽  
Wiebren De Jong ◽  
Evgeny A. Pidko ◽  
...  
Keyword(s):  
Electrochemical Reduction ◽  
Experimental Approach ◽  
Decisive Role ◽  
Experimental Methods ◽  
Reaction Intermediates ◽  
Intermediate Species ◽  
Experimental Knowledge ◽  
Complex Interactions ◽  
Ag Catalysts

<p>The analysis presented in this manuscript helps bridge an important fundamental discrepancy between the existing theoretical and experimental knowledge regarding the performance of Ag catalysts for CO<sub>2</sub> electrochemical reduction (CO<sub>2</sub>ER). The results demonstrate how the intermediate species *OCHO is formed readily en-route the HCOO<sup>– </sup>pathway and plays a decisive role in determining selectivity of a predominantly CO producing catalyst such as Ag. Our theoretical and experimental approach develops a better understanding of the nature of competition as well as the complex interactions between the reaction intermediates leading to CO, HCOO<sup>–</sup> and H<sub>2</sub> during CO<sub>2</sub>ER.</p><p><br></p><p>Details of computational and experimental methods are present in the Supporting Information provided. </p><p><br></p><p><br></p>

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