Saturation of magnetic field effects due to the ∆g mechanism

Magnetic field effects (MFEs) due to the∆g mechanism on the hydrogen abstraction reaction of 4-methoxybenzophenone with thiophenol in 2-methyl-1-propanol were studied at 293K by a laser flash photolysis technique under ultrahigh magnetic fields of up to 28T. The yield of the escape ketyl radical decreased with increasing magnetic field from 0 to 10T. The decrease, however, was almost saturated at 20T and the yield above 20T reduced to be 2/3 of that at 0T. This is the first observation of the saturation of the MFEs due to the isotropic ∆g mechanism in the reactions through radical pairs in solution.