Evaluation of reactivity for nitroxide radical trapping by correlation analysis using steric substituent parameter (?S)
✍ Scribed by Iwao, Keiji; Sakakibara, Kazuhisa; Hirota, Minoru
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 181 KB
- Volume
- 19
- Category
- Article
- ISSN
- 0192-8651
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✦ Synopsis
The reactivity of nitroxide radical trapping NRT , where stable nitroxide radicals react with transient carbon-centered radicals to form diamagnetic molecules, was evaluated. This was done with the use of the steric substituent parameter of both radicals by correlation analysis on the basis of the reactivity data determined by Ingold's group. In the case where the transient carbon-centered radicals were not resonance stabilized, the rate constant could be well correlated by using only ⍀ parameters of R NOؒ and Uؒ. If the s 2 transient radicals were stabilized by resonance, the parameter to estimate the amount of the resonance stabilization of Uؒ was necessary in the regression equation to evaluate the reactivity correctly. When the spin density, calculated by PM3 UHF molecular orbital calculations, was used as the resonance stabilization parameter, the rate constant could be well evaluated by a dualparameter regression equation.