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Volumn 125, Issue 27, 2003, Pages 8318-8329

Hydrogen-bonding effects on the properties of phenoxyl radicals. An EPR, kinetic, and computational study

Author keywords

[No Author keywords available]

Indexed keywords

ACTIVATION ENERGY; HYDROGEN BONDS; MOLECULAR STRUCTURE; OXYGEN; PARAMAGNETIC RESONANCE;

EID: 0038005812     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja034963k     Document Type: Article
Times cited : (115)

References (76)
  • 37
    • 0037062864 scopus 로고    scopus 로고
    • Very recently, it has been reported that in sterically crowded 2,6-di-tertbutylated phenols a small interaction between the phenolic hydroxyl group and HBA molecule is possible only when the orientation of the OH group is perpendicular to the aromatic plane. Litwinienko, G.; Megiel, E.; Wojnicz, M. Org. Lett. 2002, 4, 2425-2428.
    • (2002) Org. Lett. , vol.4 , pp. 2425-2428
    • Litwinienko, G.1    Megiel, E.2    Wojnicz, M.3
  • 41
    • 0038701372 scopus 로고    scopus 로고
    • note
    • In the case of BHQ, the EPR spectral parameters of the observed radicals were consistent with the phenoxyl radical centered on the hindered oxygen atom. Actually, the spectrum of the phenoxyl radical showed coupling of the unpaired electron with the two meta-protons (0.88 G) and with the remaining hydroxyl proton (1.40 G). The formation of the other possible species, with the radical centered on the oxygen in position 4, can be discarded because larger splittings (ca. 6.5 G) from the protons in 3 and 5 would be expected in this case.
  • 42
    • 0038025027 scopus 로고    scopus 로고
    • note
    • The increase of the hfs constants at the nuclei of the para substituent observed in HFP can be explained on the basis of the polar mesomeric structure H involving spin delocalization on the substituent.
  • 46
    • 0037687061 scopus 로고    scopus 로고
    • note
    • 18
  • 56
    • 0038701369 scopus 로고    scopus 로고
    • note
    • 27 on the equilibrium between a 2,6-di-tert-butyl substituted phenol and an unhindered phenol has been previously investigated. On changing the solvent from benzene to HBA solvent, the BDEs were found to increase by ca. 2 kcal/mol for phenols without ortho substituents, while in 2,6-di-tert-butyl substituted phenols they seem to be substantially unaffected. This behavior has been interpreted by admitting that the BDE increase observed in HBA solvents is essentially due to the solvation of the hydroxylic hydrogen which stabilizes the phenol, leaving the energy of the phenoxyl radical unaltered.
  • 58
    • 0038363079 scopus 로고    scopus 로고
    • Unpublished results
    • Unpublished results.
  • 64
    • 0038363080 scopus 로고    scopus 로고
    • note
    • Under our conditions, products deriving from the reactions between phenoxyl and alkyl radical to give radical-radical recombination products were not observed.
  • 65
    • 0000681444 scopus 로고
    • The first report providing clear quantitative evidence of the role that hydrogen bonding plays on the H-atom donor activities of phenols has been reported by Ingold and co-workers: Avila, D. V.; Ingold, K. U.; Lusztyk, J.; Green, W. H.; Procopio, D. R. J. Am. Chem. Soc. 1995, 117, 2929-2930.
    • (1995) J. Am. Chem. Soc. , vol.117 , pp. 2929-2930
    • Avila, D.V.1    Ingold, K.U.2    Lusztyk, J.3    Green, W.H.4    Procopio, D.R.5


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.