1,5-(1,7)-Biradicals and Nitrenes Formed by Ring Opening of Hetarylnitrenes

2013 ◽  
Vol 66 (3) ◽  
pp. 286 ◽  
Author(s):  
Curt Wentrup ◽  
David Kvaskoff
Keyword(s):  
Electron Spin Resonance ◽  
Nitrogen Atom ◽  
Low Temperature ◽  
Electron Spin ◽  
Ring Opening ◽  
Matrix Isolation ◽  
Diazo Compounds ◽  
Spin Resonance ◽  
Ring Nitrogen ◽  
Ring Nitrogen Atom

Several aromatic and heteroaromatic nitrenes and carbenes undergo photochemical and sometimes also thermal ring opening. Depending on benz-annelation, the ring-opened species may have the character of either nitrenes (for α-annelation) or 1,5-(1,7-)-biradicals (for β-annelation). Both types have been observed, and they are clearly distinguished by their characteristic electron spin resonance spectra. In addition, ring opening of hetarylnitrenes to nitrile ylides can be observed whenever there is a meta-relationship between a ring nitrogen atom and the nitrene (or carbene) centre. The factors governing the two types of ring opening have been investigated. The nitrenes and carbenes are generated by either low temperature Ar matrix photolysis or flash vacuum thermolysis of azides, tetrazoles, triazoles, or diazo compounds with matrix isolation of the products.

Applications of ESR to Carbonaceous Materials

1982 ◽  
Vol 36 (1) ◽  
pp. 52-57 ◽  
Author(s):  
L. S. Singer ◽  
I. C. Lewis
Keyword(s):  
Free Radicals ◽  
Electron Spin Resonance ◽  
Low Temperature ◽  
Electron Spin ◽  
Paramagnetic Species ◽  
Carbonaceous Materials ◽  
Conduction Electrons ◽  
Spin Resonance ◽  
Higher Temperature ◽  
Low Temperature Pyrolysis

The applications of electron spin resonance (ESR) to carbonaceous materials are reviewed. The stable paramagnetic species observed in the products of low-temperature pyrolysis are odd-alternate neutral free radicals, whereas the unpaired spins of higher temperature carbons and graphites are primarily conduction electrons. The variety of ESR properties and phenomena requires special attention to techniques of measurement and interpretations of results. The relevance to the carbonization process of the free radicals observed by ESR is also discussed.

Electron spin resonance matrix isolation studies of 27Al16,17O, 69,71Ga16,17O and 115In16,17O: Observed hyperfine interactions compared with ab initio theoretical results

1997 ◽  
Vol 107 (18) ◽  
pp. 7011-7019 ◽  
Author(s):  
Lon B. Knight ◽  
Thomas J. Kirk ◽  
John Herlong ◽  
John G. Kaup ◽  
E. R. Davidson
Keyword(s):  
Electron Spin Resonance ◽  
Ab Initio ◽  
Electron Spin ◽  
Hyperfine Interactions ◽  
Matrix Isolation ◽  
Spin Resonance ◽  
Theoretical Results

Low-temperature radiolysis of organic phosphates studied by electron spin resonance

1973 ◽  
Vol 5 (4) ◽  
pp. 351-360 ◽  
Author(s):  
K.D. Haase ◽  
D. Schulte-Frohlinde ◽  
P. Kouřím ◽  
K. Vacek
Keyword(s):  
Electron Spin Resonance ◽  
Low Temperature ◽  
Electron Spin ◽  
Organic Phosphates ◽  
Spin Resonance

Paramagnetic resonance and optical absorption of trapped holes and electrons in irradiated KCI: Ag

1963 ◽  
Vol 271 (1345) ◽  
pp. 243-267 ◽  
Keyword(s):  
Electron Spin Resonance ◽  
Low Temperature ◽  
Optical Absorption ◽  
Electron Spin ◽  
Optical Absorption Spectra ◽  
Paramagnetic Resonance ◽  
Spin Resonance ◽  
Impurity Ions ◽  
Temperature Irradiation ◽  
Positive Holes

The electron spin resonance and optical absorption spectra of crystals of KCl containing silver impurity ions were examined after the crystals had been X -irradiated at 77 °K. It is shown that the silver impurity ions act as traps for both electrons and positive holes. A description is given of the annealing behaviour of the crystals after low-temperature irradiation.

Benzoylmethyl radicals. Matrix isolation electron spin resonance study

1974 ◽  
Vol 96 (22) ◽  
pp. 6864-6868 ◽  
Author(s):  
Paul H. Kasai ◽  
D. McLeod ◽  
Henry C. McBay
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Matrix Isolation ◽  
Electron Spin Resonance Study ◽  
Spin Resonance ◽  
Spin Resonance Study

Low-Temperature Anomaly of Electron-Spin Resonance in Dilute Alloys

1967 ◽  
Vol 18 (23) ◽  
pp. 994-997 ◽  
Author(s):  
H. J. Spencer ◽  
S. Doniach
Keyword(s):  
Electron Spin Resonance ◽  
Low Temperature ◽  
Electron Spin ◽  
Temperature Anomaly ◽  
Dilute Alloys ◽  
Spin Resonance

Low‐temperature electron spin resonance investigations of silicon paramagnetic defects in silicon nitride

1991 ◽  
Vol 58 (21) ◽  
pp. 2417-2419 ◽  
Author(s):  
W. L. Warren ◽  
F. C. Rong ◽  
E. H. Poindexter ◽  
J. Kanicki ◽  
G. J. Gerardi
Keyword(s):  
Electron Spin Resonance ◽  
Silicon Nitride ◽  
Low Temperature ◽  
Electron Spin ◽  
Spin Resonance ◽  
Temperature Electron
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