TY - JOUR
T1 - Reversible photochemistry, photo-oxidation, and fluorescence of dixanthylidene
T2 - Temperature and external spin-orbit perturbation effects
AU - Korenstein, Rafi
AU - Muszkat, Karol A.
AU - Slifkin, Michael A.
AU - Fischer, Ernst
PY - 1976
Y1 - 1976
N2 - A detailed experimental study of the photochemistry of dixanthylidene over a wide temperature range indicates the existence of three labile photoisomers, B, C, and P, all of which revert thermally to A. Light-stable B, formed from the excited triplet of the fundamental modification A, is thermally stable below -140°. The structure of B involves torsion of ca. 50° about the central double bond. C And its possible precursor P are photolabile isomers formed from excited singlet A. They are photocyclisation products of the 4a,4b-dihydrophenanthrene type: C is photoconvertible into A. The thermal stability of P is much less than that of C. Helixanthen is obtained on thermal dehydro-genation of C with molecular oxygen or iodine. The quantum yield of A →hv B drops with the temperature and is very small at -140° but can be strongly enhanced (up to 220-fold) by the spin-orbit coupling perturbers molecular oxygen, carbon disulphide, and ethyl iodide.
AB - A detailed experimental study of the photochemistry of dixanthylidene over a wide temperature range indicates the existence of three labile photoisomers, B, C, and P, all of which revert thermally to A. Light-stable B, formed from the excited triplet of the fundamental modification A, is thermally stable below -140°. The structure of B involves torsion of ca. 50° about the central double bond. C And its possible precursor P are photolabile isomers formed from excited singlet A. They are photocyclisation products of the 4a,4b-dihydrophenanthrene type: C is photoconvertible into A. The thermal stability of P is much less than that of C. Helixanthen is obtained on thermal dehydro-genation of C with molecular oxygen or iodine. The quantum yield of A →hv B drops with the temperature and is very small at -140° but can be strongly enhanced (up to 220-fold) by the spin-orbit coupling perturbers molecular oxygen, carbon disulphide, and ethyl iodide.
UR - http://www.scopus.com/inward/record.url?scp=37049100784&partnerID=8YFLogxK
U2 - 10.1039/P29760000438
DO - 10.1039/P29760000438
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AN - SCOPUS:37049100784
SN - 1472-779X
SP - 438
EP - 443
JO - Journal of the Chemical Society, Perkin Transactions 2
JF - Journal of the Chemical Society, Perkin Transactions 2
IS - 4
ER -