S. Sasaki et al., Magnetic field effects on the triplet exciplex dynamics in the duroquinone-N, N-dimethylaniline derivative systems, RES CHEM IN, 27(1-2), 2001, pp. 155-164
Magnetic field effects (MFEs) on the radical yield in the photoinduced elec
tron transfer reaction from the p-halogen derivatives (4XDMA) of N,N-dimeth
ylaniline to the excited trip]et state of duroquinone (DQ) have been invest
igated in alcoholic solutions at room temperature. In I-propanol and I-buta
nol solutions, the radical yields decreased as the magnetic field increased
and became nearly constant at 1-1.8 T in the DQ-4BrDMA and DQ-4IDMA system
s, suggesting that the spin-orbit coupling interaction due to the heavy ato
ms governs the radical yield. On the other hand, in the methanol solution M
FE due to a radical pair mechanism was observed. We concluded that the key
intermediate to determine the radical yield is the triplet exciplex or cont
act radical ion pair in the l-propanol and l-butanol solutions, while it is
the solvent-separated radical ion pair in the methanol solution.