scholarly journals Rate Constants of Hydroperoxyl Radical Addition to Cyclic Nitrones:  A DFT Study

2007 ◽  
Vol 111 (39) ◽  
pp. 9995-10001 ◽  
Author(s):  
Frederick A. Villamena ◽  
John K. Merle ◽  
Christopher M. Hadad ◽  
Jay L. Zweier
Keyword(s):  
Rate Constants ◽  
Radical Addition ◽  
Dft Study ◽  
Hydroperoxyl Radical ◽  
Cyclic Nitrones

Rate constants for reactions of ethylbenzene with hydroperoxyl radical

2013 ◽  
Vol 160 (1) ◽  
pp. 9-16 ◽  
Author(s):  
Mohammednoor Khalil Altarawneh ◽  
Bogdan Z. Dlugogorski ◽  
Eric M. Kennedy ◽  
John C. Mackie
Keyword(s):  
Rate Constants ◽  
Hydroperoxyl Radical

Kinetics studies of rapid strain-promoted [3+2] cycloadditions of nitrones with bicyclo[6.1.0]nonyne

2014 ◽  
Vol 92 (4) ◽  
pp. 337-340 ◽  
Author(s):  
Douglas A. MacKenzie ◽  
John Paul Pezacki
Keyword(s):  
Rate Constants ◽  
Substituent Effect ◽  
Reaction Rates ◽  
Reaction Vessel ◽  
Second Order ◽  
Cyclic Nitrones ◽  
Organic Azides ◽  
Kinetics Studies ◽  
Bioorthogonal Labeling ◽  
Potential Applications

Strain-promoted alkyne−nitrone cycloaddition (SPANC) reactions represent a bioorthogonal labeling strategy that is both very rapid and at the same time efficient and selective. Nitrones provide increased reaction rates as well as greater susceptibility toward stereoelectronic modification when compared with organic azides. We find that strain-promoted cycloadditions of cyclic nitrones with bicyclo[6.1.0]nonyne react with second-order rate constants as large as 1.49 L mol−1 s−1 at 25 °C. These reactions display rate constants that are up to 37-fold greater than those of the analogous reactions of benzyl azide with bicyclo[6.1.0]nonyne. We observed that reactions of nitrones with bicyclo[6.1.0]nonyne showed a stronger dependence on substituent effect for the reaction, as evidenced by a larger Hammett ρ value, than that for biaryl-aza-cyclooctanone. We demonstrate the ability to stereoelectronically tune the reactivity of nitrones towards different cyclooctynes in SPANC reactions. This ability to introduce selectivity into different SPANC reactions through substituent provides the opportunity to perform multiple SPANC reactions in one reaction vessel and opens up potential applications in multiplex labeling.

A DFT study of 1,3-dipolar cycloadditions of cyclic nitrones to unsaturated lactones. Part II

2008 ◽  
Vol 19 (18) ◽  
pp. 2140-2148 ◽  
Author(s):  
Sebastian Stecko ◽  
Konrad Paśniczek ◽  
Carine Michel ◽  
Anne Milet ◽  
Serge Perez ◽  
...  
Keyword(s):  
Dft Study ◽  
Dipolar Cycloadditions ◽  
Cyclic Nitrones ◽  
Unsaturated Lactones

Synthesis and spin trapping kinetics of new alkyl substituted cyclic nitrones

1982 ◽  
Vol 60 (12) ◽  
pp. 1514-1522 ◽  
Author(s):  
D. L. Haire ◽  
Edward G. Janzen
Keyword(s):  
Comparative Study ◽  
Rate Constants ◽  
Spin Trap ◽  
Spin Trapping ◽  
Absolute Rate ◽  
Cyclic Nitrones ◽  
The Absolute ◽  
Kinetics Of

Three new nitrones, 5-n-propyl-5-methyl-1-pyrroline-N-oxide (PMPO), 5-n-hexyl-5-methyl-1-pyrroline-N-oxide (HMPO), and 5-n-decyl-5-methyl-1-pyrroline-N-oxide (DeMPO), amphiphilic versions of the spin trap 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), have been synthesized. A comparative study of the absolute rate constants for formation and decay of the tert-butoxyl spin adducts to these cyclic nitrones as well as 3,3,5,5-tetramethyl-1-pyrroline-N-oxide (M4PO) has been undertaken using esr kinetic techniques.

Rate constants for radical addition to olefins

1977 ◽  
Vol 26 (1) ◽  
pp. 4-8
Author(s):  
O. A. Ponomarev ◽  
T. M. Martem'yanova ◽  
A. I. Ivanov
Keyword(s):  
Rate Constants ◽  
Radical Addition

scholarly journals Chemical insights into the atmospheric oxidation of thiophene by hydroperoxyl radical

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Maryam Seyed Sharifi ◽  
Hamed Douroudgari ◽  
Morteza Vahedpour
Keyword(s):  
Rate Constants ◽  
Potential Energy Surfaces ◽  
Hydrogen Abstraction ◽  
State Theory ◽  
Stationary Points ◽  
Positive Temperature ◽  
Oxidation Reactions ◽  
Hydroperoxyl Radical ◽  
Title Reaction ◽  
High Level

AbstractThe reaction mechanisms and kinetics of thiophene oxidation reactions initiated by hydroperoxyl radical, and decomposition of the related intermediates and complexes, have been considered herein by using high-level DFT and ab initio calculations. The main energetic parameters of all stationary points of the suggested potential energy surfaces have been computed at the BD(T) and CCSD(T) methods, based on the geometries optimized at the B3LYP/6-311 + g(d,p) level of theory. Rate constants of bimolecular reactions (high-pressure limit rate constants) at temperatures from 300 to 3000 K for the first steps of the title reaction have been obtained through the conventional transition state theory (TST), while the pressure dependent rate constants and the rate constants of the second and other steps have been calculated employing the Rice–Ramsperger–Kassel–Marcus/Master equation (RRKM/ME). The results show that the rate constants of addition to α and β carbons have positive temperature dependence and negative pressure dependence. It is found that the additions of HO2 to the α and β carbons of thiophene in the initial steps of the title reaction are the most favored pathways. Also, the addition to the sulfur atom has a minor contribution. But, all efforts for simulating hydrogen abstraction reactions have been unsuccessful. In this complex oxidation reaction, about 12 different products are obtained, including important isomers such as thiophene-epoxide, thiophene-ol, thiophene-oxide, oxathiane, and thiophenone. The calculated total rate constants for generation of all minimum stationary points show that the addition reactions to the α and β carbons are the fastest among all at temperatures below 1000 K, while the proposed multi-step parallel reactions are more competitive at temperatures above 1200 K. Furthermore, important inter-and intra-molecular interactions for some species have been investigated by two well-known quantum chemistry method, the NBO and AIM analyses. Thermochemical properties such as free energy, enthalpy, internal energy, and entropy for thiophene and hydroperoxyl radical and related species in the simulated reactions have been predicted using a combination of the B3LYP and BD(T) methods.

A DFT study of 1,3-dipolar cycloaddition reactions of 5-membered cyclic nitrones with α,β-unsaturated lactones and with cyclic vinyl ethers: Part 1

2008 ◽  
Vol 19 (14) ◽  
pp. 1660-1669 ◽  
Author(s):  
Sebastian Stecko ◽  
Konrad Paśniczek ◽  
Carine Michel ◽  
Anne Milet ◽  
Serge Pérez ◽  
...  
Keyword(s):  
Dft Study ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Vinyl Ethers ◽  
Cyclic Nitrones ◽  
Unsaturated Lactones
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