Electron Spin Resonance Study of γ-Irradiated Carbohydrate Ices at Low Temperatures

Nature ◽  
1969 ◽  
Vol 221 (5186) ◽  
pp. 1138-1139 ◽  
Author(s):  
P. J. BAUGH ◽  
K. KERSHAW ◽  
G. O. PHILLIPS
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Low Temperatures ◽  
Electron Spin Resonance Study ◽  
Spin Resonance ◽  
Spin Resonance Study

Organometallic peroxy radicals. Part II. A kinetic electron spin resonance study of some organogermylperoxy radicals

1976 ◽  
Vol 54 (16) ◽  
pp. 2669-2675 ◽  
Author(s):  
James Anthony Howard ◽  
John Charles Tait
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Low Temperatures ◽  
Experimental Error ◽  
Arrhenius Equation ◽  
Electron Spin Resonance Study ◽  
Peroxy Radicals ◽  
Approximate Form ◽  
Spin Resonance ◽  
Spin Resonance Study

Trimethylgermylperoxy and triphenylgermylperoxy have been prepared and their kinetic behaviour investigated by electron spin resonance techniques. At low temperatures (< −50 °C) these radicals exist in equilibrium with the tetroxide. The thermodynamic parameters for this equilibrium (−ΔH0 ≈ 11.5 kcal mol−1 and −ΔS0 ≈ 26.5 cal deg−1 mol−1) are the same, within experimental error, for both radicals. Above −50 °C (CH3)3GeO2 and (C6H5)3GeO2 decay irreversibly by a unimolecular process. (C6H5)3GeO2 is slightly less stable than (CH3)3GeO2 although both radicals appear to fit an Arrhenius equation of the approximate form log (kepr1/s−1) ≈ 5 − 6/θ where θ = 2.303RT kcal mol−1.

An Electron Spin Resonance Study of the tert-Butylsulfinyl Radical

1974 ◽  
Vol 52 (4) ◽  
pp. 555-556 ◽  
Author(s):  
James A. Howard ◽  
Edward Furimsky
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Low Temperatures ◽  
Half Life ◽  
Electron Spin Resonance Study ◽  
Tert Butyl ◽  
Field Center ◽  
Spin Resonance ◽  
Butyl Peroxide ◽  
Spin Resonance Study

The tert-butylsulfinyl radical, (CH3)3CSO•, can be prepared directly in the cavity of an e.p.r. spectrometer by photolysis of di-tert-butyl peroxide in a solution of tert-butylsulfenic acid in toluene or isopentane at low temperatures (−40° to−100°). The e.s.r. spectrum consists of a rather broad singlet (ΔHmis ∼ 1.9 G) with the field center at g = 2.0106.This radical undergoes self-reaction by a bimolecular process and a 2.5 × 10−7 M solution has a half-life of 0.07 s at −100 °C. It is, therefore, much shorter-lived than the iso-structural tert-butylperoxy radical, (CH3)3COO•.

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