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PHOTOREDUCTION OF PORPHYRINS TO CHLORINS BY TERTIARY AMINES IN THE VISIBLE SPECTRAL RANGE. OPTICAL AND EPR STUDIES
Author(s) -
Harel Yaacov,
Manassen Joost,
Leva Haim
Publication year - 1976
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1976.tb07258.x
Subject(s) - photochemistry , chlorin , porphyrin , chemistry , flash photolysis , electron paramagnetic resonance , yield (engineering) , visible spectrum , amine gas treating , free base , photodissociation , radical , singlet state , dimer , tertiary amine , singlet oxygen , excited state , materials science , polymer chemistry , organic chemistry , kinetics , reaction rate constant , nuclear magnetic resonance , physics , optoelectronics , quantum mechanics , salt (chemistry) , oxygen , nuclear physics , metallurgy
— The photoreduction of free base porphyrins by tertiary amines in the visible spectral range leads to the formation of chlorin. The increase of the apparent first order rates to yield chlorin is correlated with the inductive effect on the nitrogen of the amine used. A mechanism involving a charge transfer interaction between the photoexcited singlet of the prophyrin and the amine is proposed. The porphyrin radicals formed recombine to form a light sensitive dimer which disproportionates in the dark to yield chlorin and porphyrin. The mechanism is elucidated by the use of EPR, laser and flash photolysis.