Abstract
New strategy for the molecular design of stable diarylnitroxides was elaborated based on the insertion of a bulky substituent into the ortho-position of the phenyl ring thus disturbing its conjugation with the radical center. A series of new twisted diaryl nitroxides with tert-butyl and trifluoromethyl substituents in different positions and combinations was obtained and fully characterized. Electron spin resonance (ESR) and density functional theory (DFT) studies confirmed that the ortho-substituted phenyl ring is removed from the conjugation; the O–N–C–C torsion angle was shown to be dependent not only on the bulkiness of the ortho-substituent, but it is also influenced by the electron-donating or electron-withdrawing ability of the substituents in both phenyl rings. These nitroxides constitute the first examples of stable diarylnitroxides with a vacant para-position on the phenyl ring. The new approach will broaden the scope of available stable diarylnitroxyl radicals, which are practically important.
Original language | English |
---|---|
Pages (from-to) | 4726-4735 |
Number of pages | 10 |
Journal | European Journal of Organic Chemistry |
Volume | 2017 |
Issue number | 32 |
DOIs | |
Publication status | Published - 1 Sept 2017 |
Externally published | Yes |
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry
- Organic Chemistry