APPLICATION OF TIME-RESOLVED-PULSED-EPR SPECTROSCOPY TO STUDY PHOTOINDUCED ELECTRON-TRANSFER REACTIONS - PORPHYRIN QUINONE SYSTEM

Characteristic features of the time-resolved fourier transform EPR (FT -EPR) and electron spin echo FT-EPR (ESE-FT-EPR) spectroscopies for st udies of photochemical reaction kinetics are summarized in comparison with the cw-time-resolved EPR (CW-TREPR) spectroscopy. The former two methods were applied to study the photoinduced electron transfer react ion between zinc tetraphenylporphyrin (ZnTPP) and benzoquinone (BQ) in 2-butanol. It is shown that deuterium substitution of the compounds a nd an application of the ESE-FT-EPR method are effective to observe th e broad EPR spectrum of the ZnTPP cation which is missed in measuremen ts by FT-EPR. The kinetic data obtained for the deuterated and undeute rated compounds are compared.