Viscosity Dependence of the Magnetic Field Effect Due to the Δg Mechanism

We investigated the magnetic field effect on the yields of the escaping radicals formed by the hydrogen abstraction reaction of excited triplet 4-methoxybenzophenone with 4-chlorothiophenol in mixtures of 2-propanol and cyclohexanol. The yields of the escaping radicals decreased with increasing external magnetic field owing to the Δg mechanism. The relative yield of the escaping radicals to that in the absence of the external magnetic field in 2-propanol was 0.9 at 1.4 T. The magnetic field effects in a nonviscous solution such as 2-propanol were proportional to the square root of the external magnetic field and the solvent viscosity, (Bη)1/2. However, the deviation from this relationship, the decrease in the exponent, was observed by increasing the solvent viscosity, up to 60 cP. The relative yield in cyclohexanol was 0.88 at 0.8 T and roughly constant up to 1.4 T.