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U.S. Department of Energy
Office of Scientific and Technical Information

Investigation of the structure of photosynthetic reaction centers. Final report, June 1, 1981-May 31, 1984

Technical Report ·
OSTI ID:7119211
A spectroscopic study was made of some water-soluble porphyrins. Dimer formation of tetra(4-sulfonatophenyl)porphyrin and its Zn and Pd complexes has been studied using optical and triplet ESR spectroscopy. The data give information on dimer geometry as well as on dimerization effects on photo-excited triplet properties. It is found that dimerization effects mimic those associated with a transition from in vitro bacteriochlorophyll monomers to primary donor bacteriochlorophyll in reaction centers of photosynthetic bacteria. An ENDOR study was made of the solvation of a porphyrin cation radical. The study established that the ENDOR technique can provide information on weak interactions between paramagnetic macrocycles and surrounding solvent molecules. ENDOR was applied in the study of the photo-excited triplet state of porphyrins and photosynthetic reaction centers randomly oriented in solid solution. Information on the hyperfine interactions between unpaired electrons and nuclear spins obtained with this technique gives an insight into the electronic and geometric structure of these systems.
Research Organization:
Massachusetts Univ., Boston (USA). Dept. of Chemistry
DOE Contract Number:
AC02-81ER10911
OSTI ID:
7119211
Report Number(s):
DOE/ER/10911-6; ON: DE84012475
Country of Publication:
United States
Language:
English