Simultaneous Electron Spin–Nuclear Spin Transitions in Solid Solutions of Methyl Radicals

1974 ◽  
Vol 52 (13) ◽  
pp. 2471-2474 ◽  
Author(s):  
C. T. Cazianis ◽  
D. R. Eaton
Keyword(s):  
Water Molecule ◽  
Electron Spin ◽  
Solid Solutions ◽  
Unpaired Electron ◽  
Nuclear Spin ◽  
Ultraviolet Irradiation ◽  
Methyl Radicals ◽  
Methyl Radical ◽  
Neighboring Water Molecule ◽  
Spin Transitions

The e.s.r. spectra of methyl radicals produced by the ultraviolet irradiation of Tl(III) acetate show satellites attributed to simultaneous electron spin – nuclear spin transitions involving a proton of a neighboring water molecule. Measurement of the relative intensities of the satellites and the main transitions allows the average separation of the interacting proton from the unpaired electron to be calculated. Such measurements have been carried out over the temperature range −180 to −120 °C. The implications regarding the environment of the methyl radical in the ice matrix are briefly discussed.

Electron spin resonance studies of methyl radicals stabilized on porous VYCOR glass: various surface interactions, second-order splitting, and a linewidth temperature study

1970 ◽  
Vol 48 (17) ◽  
pp. 2685-2694 ◽  
Author(s):  
G. B. Garbutt ◽  
H. D. Gesser
Keyword(s):  
Electron Spin Resonance ◽  
High Temperature ◽  
Electron Spin ◽  
Second Order ◽  
Methyl Radicals ◽  
Methyl Radical ◽  
Potential Wells ◽  
Vycor Glass ◽  
Porous Vycor Glass ◽  
Spin Resonance

Electron spin resonance studies have been performed on methyl radicals stabilized on the surface of porous VYCOR glass. As previously reported, two very different methyl radicals, denoted Me and Me′, were seen. Results indicate that the radical Me′ is most probably weakly bound to the boroxane group (=B—O—B=) which is prominent on the surface of high temperature (700–900 °C) pretreated porous VYCOR glass. Four satellite lines about each Me line, denoted previously as radical X, were observed when the surface was pretreated at lower temperatures (400–500 °C). In an earlier publication radical X was attributed to the interaction between methyl radicals and the isotopic surface species 11B. In this study two additional satellite lines about each Me line are reported as well as a reassignment of the origin of all satellite lines. Four of the six satellite lines have been assigned to forbidden "spin–flip" transitions while the other two have been assigned to direct interaction between methyl radicals and the surface hydroxyl protons. Support for the irreversibility of high temperature dehydroxylation of porous VYCOR glass is also presented.A partial resolution of the second-order splitting of each of the central pair of lines was achieved for the normal methyl radical. The value of the second-order splitting was between 220 and 230 mG. The linewidths of the two central lines were measured at 77 °K. The samples were then allowed to warm up to various temperatures and then recooled to 77 °K. The linewidths were smaller after completing this cycle. Storage of the sample at 77 °K allowed the linewidths to return to their original values. These linewidths effects are explained by postulating the existence of two different types of potential wells on the surface.

Free radicals in the reaction between t-butyl hydroperoxide and titanous ion: Some observations by electron spin resonance spectrometry

1965 ◽  
Vol 18 (8) ◽  
pp. 1177 ◽  
Author(s):  
MFR Mulcahy ◽  
JR Steven ◽  
JC Ward
Keyword(s):  
Aqueous Solution ◽  
Free Radicals ◽  
Electron Spin Resonance ◽  
Electron Spin ◽  
Peroxy Radicals ◽  
Methyl Radicals ◽  
Methyl Radical ◽  
Butyl Hydroperoxide ◽  
Spin Resonance ◽  
G Value

The reaction between t-butyl hydroperoxide and titanous ion in aqueous solution produces free methyl radicals detectable by electron spin resonance spectrometry (Dixon and Norman). However, the presence of titanous ion in concentrations greater than 0.01M broadens the spectrum of the methyl radical, causing it effectively to disappear at titanous concentrations greater than 0.1M. At hydroperoxide concentrations above 0.25M t-butyl peroxy radicals (identified by a strong single-line spectrum with g-value 2.0136) are produced by the reaction ���������� R. + (CH3)3COOH → RH + (CH3)3COO. Their concentration reaches a maximum about 1 sec after the concentration of the methyl radicals has fallen to an undetectable value and their half-life (≈ 5 sec) is about ten times that of the methyl radicals.

Electron spin resonance (ESR) investigation of the structure of methyl radical trapping sites in methanol glass

1987 ◽  
Vol 86 (12) ◽  
pp. 6622-6630 ◽  
Author(s):  
T. Doba ◽  
K. U. Ingold ◽  
A. H. Reddoch ◽  
W. Siebrand ◽  
T. A. Wildman
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Methyl Radical ◽  
Radical Trapping ◽  
Spin Resonance ◽  
Trapping Sites

Do primary carriers of both positive charge and unpaired electron spin exist in irradiated propylene carbonate?

2017 ◽  
Vol 19 (1) ◽  
pp. 49-53 ◽  
Author(s):  
V. I. Borovkov
Keyword(s):  
Magnetic Field ◽  
Propylene Carbonate ◽  
Electron Spin ◽  
Unpaired Electron ◽  
Positive Charge ◽  
Radical Cations ◽  
Carbonate Solutions ◽  
Solvent Molecules

Magnetic field sensitive fluorescence from irradiated propylene carbonate solutions indicates the existence of previously unobserved radical cations formed from the solvent molecules.

Helicene Radicals: Molecules Bearing a Combination of Helical Chirality and Unpaired Electron Spin

ChemPlusChem ◽  
2020 ◽  
Vol 85 (9) ◽  
pp. 2093-2104
Author(s):  
Fumito Tani ◽  
Masahiro Narita ◽  
Toshihiro Murafuji
Keyword(s):  
Electron Spin ◽  
Unpaired Electron ◽  
Helical Chirality
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