G. Jeschke et al., MAGNETIC-FIELD EFFECTS OBSERVED UPON PHOTOLYSIS OF PARASUBSTITUTED DIPHENYL DISULFIDES IN MICELLAR SOLUTIONS, Journal of physical chemistry, 98(15), 1994, pp. 4069-4075
The recombination of pairs of para-substituted phenylthiyl radicals in
side micellar supercages was studied by means of a nanosecond laser fl
ash photolysis technique. Singlet and triplet pairs were formed by dir
ect excitation and by triplet-sensitized photolysis of the correspondi
ng disulfides, respectively. Magnetic field effects (MFEs) on the yiel
d of escaped thiyl radicals were found for the triplet-sensitized phot
olysis of the p-amino compound. For the p-hydroxy-, p-methoxy-, and p-
butoxy compounds, short-lived MFEs were observed but it is unlikely th
at they arise from the recombination of the thiyl radicals. No MFE was
found on pairs of p-chloro-substituted and unsubstituted phenylthiyl
radicals within experimental error. The absence of MFE is in this case
explained by large spin-orbit coupling caused by orbital degeneracy.
A stabilization mechanism of the (p-aminophenyl)-thiyl radicals lifts
that degeneracy and reduces spin-orbit coupling. Variations of the MFE
over the absorption spectrum were used to assign the MFEs to certain
species in the reaction systems.