Magnetic field effects on the hydrogen abstraction reactions of triplet benzophenone with thiophenol in nonviscous homogeneous solutions

The hydrogen abstraction reaction of triplet benzophenone with thiophenol at room temperature was investigated in several nonviscous homogeneous solutions (eta = 0.29-3.33 cP) by means of a nanosecond laser flash photolysis technique under magnetic fields of 0-10 T. The escape yield of the benzophenone ketyl radical decreased with increasing magnetic field strength from 0 to 10 T. In 2-methyl-1-propanol (eta = 3.33 cP), the yield at 10 T reduced to 80 +/- 2% of that at 0 T. The observed magnetic field effects can be interpreted by the Delta g mechanism when the geminate recombination process is faster than or comparable to the escape one.