Diphenylpyridylmethyl radicals. Part 1. Synthesis, dimerization and ENDOR spectroscopy of diphenyl(2-, 3- or 4-pyridyl)methyl radicals; bond dissociation enthalpies of their dimers

1995 ◽  
pp. 755 ◽  
Author(s):  
Nikolaos I. Tzerpos ◽  
Antonios K. Zarkadis ◽  
Richard P. Kreher ◽  
Liesel Repas ◽  
Manfred Lehnig
Keyword(s):  
Methyl Radicals ◽  
Bond Dissociation ◽  
Endor Spectroscopy

EPR-ENDOR spectroscopy of matrix-isolated ammonia(1+) and methyl radicals

1991 ◽  
Vol 95 (7) ◽  
pp. 2674-2679 ◽  
Author(s):  
Allan J. McKinley ◽  
Josef Michl
Keyword(s):  
Methyl Radicals ◽  
Endor Spectroscopy

Bond Dissociation Energies and Radical Stabilization Energies Associated with Substituted Methyl Radicals

2001 ◽  
Vol 105 (27) ◽  
pp. 6750-6756 ◽  
Author(s):  
David J. Henry ◽  
Christopher J. Parkinson ◽  
Paul M. Mayer ◽  
Leo Radom
Keyword(s):  
Bond Dissociation Energies ◽  
Methyl Radicals ◽  
Bond Dissociation ◽  
Dissociation Energies ◽  
Stabilization Energies

The CH 2 : CH.CH 2 —CH 3 bond dissociation energy and the heat of formation of the allyl radical

1950 ◽  
Vol 202 (1069) ◽  
pp. 263-276 ◽  
Keyword(s):  
Bond Dissociation Energy ◽  
Dissociation Energy ◽  
Heat Of Formation ◽  
Methyl Radicals ◽  
Kcal Mole ◽  
Allyl Radical ◽  
First Order ◽  
Bond Dissociation ◽  
Benzyl Radicals ◽  
Thermal Stability Of

The pyrolysis of butene-1 was investigated by a flow technique, toluene being used as a carrier gas. It was found that butene-1 decomposed into allyl and methyl radicals according to the equation CH 2 : CH.CH 2 — CH 3 → CH 2 : CH.CH 2 + CH 3 . Methyl radicals were removed by reaction with toluene giving methane and benzyl radicals. The rate of the initial decomposition was measured by the rate of formation of methane. The decomposition was found to be a homogeneous first order gas reaction. The activation energy was calculated at 61.5 kcal./mole and it was identified with the CH 2 : CH.CH 2 — CH 3 bond dissociation energy. Taking D (CH 2 : CH.CH 2 —CH 3 ) at 61.5 kcal./mole we calculated from thermochemical data D (CH 2 : CH.CH 2 —H) at 76.5 kcal./mole and the heat of formation of allyl radical at + 30 kcal./mole. The fate of allyl radicals is discussed and the thermal stability of these is compared with that of benzyl radicals.

DFT Benchmark Study of the O--O Bond Dissociation Energy in Peroxides Validated with High-Level Ab-Initio Calculations

2019 ◽  
Author(s):  
Danilo Carmona ◽  
Pablo Jaque ◽  
Esteban Vöhringer-Martinez
Keyword(s):  
Reference Value ◽  
Basis Set ◽  
Basis Sets ◽  
Mean Deviation ◽  
Bond Dissociation ◽  
Dissociation Energies ◽  
The Mean ◽  
Experimental Values ◽  
High Level ◽  
Almost All

<div><div><div><p>Peroxides play a central role in many chemical and biological pro- cesses such as the Fenton reaction. The relevance of these compounds lies in the low stability of the O–O bond which upon dissociation results in radical species able to initiate various chemical or biological processes. In this work, a set of 64 DFT functional-basis set combinations has been validated in terms of their capability to describe bond dissociation energies (BDE) for the O–O bond in a database of 14 ROOH peroxides for which experimental values ofBDE are available. Moreover, the electronic contributions to the BDE were obtained for four of the peroxides and the anion H2O2− at the CBS limit at CCSD(T) level with Dunning’s basis sets up to triple–ζ quality provid- ing a reference value for the hydrogen peroxide anion as a model. Almost all the functionals considered here yielded mean absolute deviations around 5.0 kcal mol−1. The smallest values were observed for the ωB97 family and the Minnesota M11 functional with a marked basis set dependence. Despite the mean deviation, order relations among BDE experimental values of peroxides were also considered. The ωB97 family was able to reproduce the relations correctly whereas other functionals presented a marked dependence on the chemical nature of the R group. Interestingly, M11 functional did not show a very good agreement with the established order despite its good performance in the mean error. The obtained results support the use of similar validation strategies for proper prediction of BDE or other molecular properties by DF Tmethods in subsequent related studies.</p></div></div></div>

Photoionization of two substituted methyl radicals: Cyanomethyl and bromomethyl

2010 ◽  
Vol 500 (4-6) ◽  
pp. 232-236 ◽  
Author(s):  
Michael Steinbauer ◽  
Patrick Hemberger ◽  
Ingo Fischer ◽  
Melanie Johnson ◽  
Andras Bodi
Keyword(s):  
Methyl Radicals
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