Magnetic Field Effects Due to the ΔgMechanism upon Chemical Reactions through Radical Pairs under Ultrahigh Fields of up to 30 T

Abstract

Magnetic field effects (MFEs) due to the isotropic Δg mechanism were studied for the hydrogen abstraction reactions of 4-methoxy-benzophenone with thiophenol in several solvents at 293 K by a laser flash photolysis technique under ultrahigh magnetic fields of up to 30 T. In 2-propanol, ethanol, and methanol, the yield of the escaped ketyl radical decreased with increasing magnetic field from 0 to 30 T. In 2-methyl-1-propanol, however, the decrease was almost saturated at 20 T and the yield above 20 T reduced to be 2/3 of that at 0 T. Such saturation of the MFEs due to the isotropic Δg mechanism in the reaction through radical pairs in solution was found for the first time.

The Magnetic Field Effects on Photochemical Reactions in Ionic Liquids

“…As clearly seen in Figure 3( Figure 3(a). In a previous paper, 18 the R(B) values in 2-methyl-1-propanol were saturated above 20 T, and the observed R(B) values could be reproduced fairly well by the diffusion model. According to the diffusion model developed for the MFE in such conventional solvents, the saturated fields due to the ∆gM should decrease with increasing the solvent viscosity.…”

“…The decrease of R(B) at 0 T < B e 2 T and the saturation of MFEs at 2 T < B e 10 T can safely be explained by the ∆gM, which originates from the difference between the isotropic g factors of two radicals in a pair, 1,2,16,18 because the present radical pair of BPH• (g ) 2.0030) and •SPh (g ) 2.0082) has a large ∆g value of 0.0052. 18 Moreover, the plots of R(B) vs B 1/2 have a good linear relationship, as shown in Figure 2 (inset).…”

“…16 The saturation of MFEs due to the ∆gM has previously been reported for the similar reaction of 4-methoxybenzophenone with PhSH in nonviscous conventional solvents such as 2-methyl-1-propanol. 18 In 2-methyl-1-propanol (η < 3.3 cP), the escaping process from the radical pairs is much faster than the T-S spin conversion process. At 0 T, almost all of triplet radical pairs are escaped from the pairs.…”

Anomalous Magnetic Field Effects on Photochemical Reactions in Ionic Liquid under Ultrahigh Fields of up to 28 T

“…18 Moreover, the plots of R(B) vs B 1/2 have a good linear relationship, as shown in Figure 2 (inset). Such field dependence of the linear relationship is well-known to the MFEs due to the ∆gM.…”

High Magnetic Fields in Chemistry

“…In organic systems this can be achieved if electron spin density is localized on heavy heteroatoms. A recent example of an investigation in high magnetic fields of such a system has been reported by Wakasa et al 27 They studied the H-atom transfer reaction…”