Abstract
Application of electron spin echo Fourier transform EPR (ESE-FT-EPR) to photo-induced chemical reactions is presented. Main purpose of this study is to observe broad EPR spectra of free radicals having very shortT *2 by means of the ESE-FT-EPR technique. Details of the experimental procedures are described. In ESE experiments design of the resonator is important to obtain sufficient spectral bandwidth because of use of multiple pulses which decrease the bandwidth. We designed and constructed Loop-Gap-Resonantors (LGR) for light irradiation experiments and their specifications were examined. The phase cycling method is essential to obtain pure ESE signals and proper time resolution by eliminating unwanted FID signals which result from imperfect pulse angles. We applied this technique to observe the photo-induced electron transfer reaction between tetraphenylporphinato zinc(II) (ZnTPP) and duroquinone (DQ) in an ethanol solution, and successfully observed the time resolved EPR spectra of the both Zn(TPP) cation and DQ anion radicals by ESE-FT-EPR of the Hahn echo. The half-height full-width of envelope of EPR spectrum of Zn(TPP)+, which is never observed in ordinary FT-EPR, is about 16 MHz. Specificity of spectra and the time resolution are compared among the ESE-FT-, FT- and cw-Time-Resolved-EPR (cw-TREPR) techniques.
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Prisner T., Dobbert O., Dinse K.P., van Willigen H.: J. Am. Chem. Soc.110, 1622 (1988)
Plueschau M., Zahl A., Dinse K.P.: J. Chem. Phys.90, 3153 (1989)
van Willigen H., Vuolle M., Dinse K.P.: J. Chem. Phys.93, 2441 (1989)
Yamauchi S., Ueda T., Satoh M., Akiyama K., Tero-Kubota S., Ikegami Y., Iwaizumi M.: L. Photochem. Photobiol. A: Chem.65, 177 (1992)
Felton R.H., Dolphin D., Borg D.C., Fajer J.: J. Am. Chem. Soc.90, 196 (1969)
Glazkov Yu.V., Zhuralev A.G., Kuzovkov P.V., Shulga A.U.: Zh. Prikl. Spektrosk.8, 117 (1973)
Milov A.D., Shirov M.D., Khmelinskii V.E., Tsvetkov Yu.D.: Dokl. Akad. Nauk SSSR218, 878 (1974)
Trifunac A.D., Norris J.R.: Chem. Phys. Lett.59, 140 (1978)
Froncisz W., Hyde J.S.: J. Magn. Reson.47, 515 (1982)
Gorcester J., Millhauser G.L., Freed J.H.: Modern Pulsed and Continuous-Wave Electron Spin Resonance, p. 167. New York: John Wiley and Sons 1990.
Hoult D.I., Richards R.E.: Proc. R. Soc. LondonA344, 311 (1975)
Fajer J., Davis M.S.: The Porphirins, vol.IV (Dolphin D., ed.). p. 200. New York: Academic Press 1979.
Ohba Y., Satoh R., Kikuchi T., Yamauchi S., Iwaizumi M.: J. Magn. Reson., in press.
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Ohba, Y., Okabe, N., Satoh, R. et al. Observation of broad EPR spectra of transient free radicals by FT-EPR. Appl. Magn. Reson. 6, 51–66 (1994). https://doi.org/10.1007/BF03162481
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DOI: https://doi.org/10.1007/BF03162481