摘要:

AbstractElectron transfer reactions between the photoexcited triplets of several porphyrin and chlorophyll precursors,3P (electron donors), and neutral duroquinone, DQ (electron acceptor), were studied by selective laser excitation‐Fourier transform (FT)‐EPR spectroscopy. Four different P, which are related to the photosynthetic apparatus, were examined in ethanol solutions at −243 K: pyrochlorophylla(pChla), zinc‐pyrochlorophylla(ZnpChla), zinc‐tetraphenylporphyrin (ZnTPP), and magnesium‐tetraphenylporphyrin (MgTPP). This highly time‐resolved EPR spectroscopy (∼10 ns delay time, ẗd, between the laser excitation and the detection pulse) permits differentiation between the various CIDEP mechanisms, i.e., triplet mechanism (TM) and radical‐pair mechanism (RPM), associated with the electron transfer process. The spectra of the DQ.−generated by the different triplet precursors strongly depend on two inherent parameters characteristic of the molecular system: (1) the zero‐field splitting (ZFS) and the selective singlet‐triplet (Ti l̊ S1) population rates, Ai(i = x, y, z); (2) the difference ing‐values and hyperfine components between the donor and acceptor radicals. Since the differences ing‐values and hyperfines are very nearly the same in all four P.+‐DQ.−systems examined, the different results, particularly in the time range 10 ns<ẗ

ISSN:0021-2148    

DOI:10.1002/ijch.198800032

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

ISSN:0021-2148    

DOI:10.1002/ijch.198800011

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY