EPR study of gamma irradiated 2,5-di-tert-butyl-hydroquinone single crystals
Küçük Resim Yok
Tarih
2011
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
PERGAMON-ELSEVIER SCIENCE LTD
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
gamma-irradiated single crystals of 2,5-di-tert-butyl-hydroquinone (DTBHQ) were investigated using the electron paramagnetic resonance (EPR) technique. The spectra of the crystals at different orientations in the magnetic field between temperatures of 120 and 450 K, were found to be temperature dependent. Taking into consideration the chemical structure and the experimental spectra of the irradiated single crystals of DTBHQ we assumed that one or more paramagnetic species were produced, each having an unpaired electron delocalized in the phenyl ring. Pursuant to this assumption, four possible radicals were modeled using the B3LYP/6-31+G(d) level of density-functional theory. EPR parameters were calculated for these modeled radicals using the B3LYP method and TZVP basis set. The calculated hyperfine-coupling constants were used as starting points for simulations. The experimental and simulated spectra for each of the three crystallographic axes were well matched for the modeled radical R4; we thus identified the hydroquinone anion radical as a paramagnetic species produced in DTBHQ. The experimental g-factor of the hydroquinone anion radical were found to be anisotropic with the average value g(iso)=2.0096. The hyperfine coupling constants of the H-alpha proton was found anisotropic with the average value (a(H7)(alpha))(iso) = 6.3 G and H-beta proton was found isotropic with the average value (a(H8)(beta))= 3.5 G. (C) 2010 Elsevier Ltd. All rights reserved.
Açıklama
Anahtar Kelimeler
EPR, Spectroscopic splitting factor, g-factor, Isotropic hyperfine coupling constant a, OFT calculations, 2,5-di-tert-butyl-hydroquinone (DTBHQ)
Kaynak
RADIATION PHYSICS AND CHEMISTRY
WoS Q Değeri
Q2
Scopus Q Değeri
Q2
Cilt
80
Sayı
1
