Electron spin resonance determination of hindered rotation in benzyl radicals. Resonance stabilization energy

1979 ◽  
Vol 83 (16) ◽  
pp. 2160-2161 ◽  
Author(s):  
Mark S. Conradi ◽  
Henry. Zeldes ◽  
Ralph. Livingston
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Stabilization Energy ◽  
Hindered Rotation ◽  
Spin Resonance ◽  
Benzyl Radicals ◽  
Resonance Stabilization

Substituent effects on benzyl radical hydrogen hyperfine coupling constants (hfc's).: Part 5. The comparison of electron spin resonance hfc's and the stabilization energy of π-radicals due to spin delocalization

1986 ◽  
Vol 64 (2) ◽  
pp. 270-276 ◽  
Author(s):  
A. Martin de P. Nicholas ◽  
Donald R. Arnold
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Substituent Effects ◽  
Energy Scale ◽  
Spin Systems ◽  
Stabilization Energy ◽  
Coupling Constants ◽  
Spin Resonance ◽  
Benzyl Radicals ◽  
Spin Delocalization

Electron spin resonance (esr) hfc values of π-radicals are found to be linearly related to the stabilization energy due to spin delocalization. Application of this relationship to benzyl radicals permits the representation of σ•α values on an energy scale. Mulliken charges in the α- and β-spin systems are found to provide valuable information about factors governing the effects of substituents on spin delocalization in benzyl radicals. These effects can be rationalized by considering four types of spin–spin interactions involving σ- and π-electrons in the α- and β-spin systems. The Mulliken analysis shows that all substituents are stronger π α-acceptors (or weaker π α-donors) at the para position relative to the meta position. Similarly, in the 3 system the meta derivatives are the better acceptors. This may be understood in terms of the excess of π α-spin at the para-carbon and the excess of π β-spin at the meta-carbon. Similar effects are observed in the a framework.

Electron-spin-resonance determination of the internal field within the superconductorYBa2Cu3O7

1990 ◽  
Vol 41 (4) ◽  
pp. 2046-2048 ◽  
Author(s):  
Horacio A. Farach ◽  
Eduardo Quagliata ◽  
Taha Mzoughi ◽  
Manuel A. Mesa ◽  
Charles P. Poole ◽  
...  
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Internal Field ◽  
Spin Resonance

A comparison of electron spin resonance α- and β-hyperfine coupling constants in para-substituted α-phenethyl radicals

1986 ◽  
Vol 64 (4) ◽  
pp. 769-772 ◽  
Author(s):  
Donald R. Arnold ◽  
A. Martin de P. Nicholas ◽  
Kent M. Young
Keyword(s):  
Electron Spin Resonance ◽  
Experimental Evidence ◽  
Linear Relationship ◽  
Electron Spin ◽  
Hyperfine Coupling ◽  
Coupling Constants ◽  
Hyperfine Coupling Constants ◽  
Spin Resonance ◽  
Benzyl Radicals ◽  
Spin Delocalization

The linear relationship between the electron spin resonance hyperfine coupling constants (hfc) of the α- and β-hydrogens of para-substituted α-phenethyl radicals provides experimental evidence that the magnitude of both the α- and β -hfc is determined largely by the extent of spin delocalization in these benzylic systems. The [Formula: see text] scale, developed using substituted benzyl radicals, is shown to apply to phenethyl radicals as well.

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