Identification of radiation-induced radical structure in azocalix[4]arene: an EPR study

Usta K., Karakus O. O., Usta A., Deligoz H.

MAGNETIC RESONANCE IN CHEMISTRY, cilt.51, sa.10, ss.671-675, 2013 (SCI-Expanded) identifier identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 51 Sayı: 10
  • Basım Tarihi: 2013
  • Doi Numarası: 10.1002/mrc.3998
  • Dergi Adı: MAGNETIC RESONANCE IN CHEMISTRY
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.671-675
  • Anahtar Kelimeler: azocalix[4]arene, chemical synthesis, electron paramagnetic resonance (EPR), irradiation effects, CALIXARENES, EXTRACTION
  • Akdeniz Üniversitesi Adresli: Evet

Özet

A macrocyclic azocalix[4]arene (1) based ester derivative was synthesized. The single crystals of azocalix[4]arene were produced by slow evaporation of concentrated ethyl acetate solutions. These single crystals were exposed to Co-60 gamma rays with a dose rate of 0.980 kGy h(-1) for 48 and 72h to produce a stable free radical. Electron paramagnetic resonance (EPR) measurements were performed in three mutually perpendicular planes of the single crystal in the magnetic field, in addition, temperature dependence of the EPR signal was studied between 120K and 450K. The spectra were found to be temperature and angular dependent. Analysis based on the spectra recorded showed that a free radical was formed by fission of a C-H bond. This radical is described as (CaHCbH3)-C-center dot The averages of the principal values of the hyperfine parameters and g-factor are: g=2.0034, A(Ha)=1.28 mT, A(H1=H2)=1.00 mT, and A(H3)=0.49 mT. Copyright (c) 2013 John Wiley & Sons, Ltd.