EPR studies on H-abstraction from p-substituted benzaldehydes by new “Magic Blue” reagents and correlation analysis of aN values of ω-fluorosulfonylperfluoroalkyl p-substituted benzoyl nitroxides

New “Magic Blue” reagent, namely, the blue solution in F113 (CClF2CCl2F) containing H-abstracting agent bis[ω-fluorosulfonylperfluoroalkyl] nitroxide RFN(O)RF 2 and ω-fluorosulfonylperfluoronitrosoalkane spin trap RFNO 3 both generated in the reaction of ω-fluorosulfonylperfluorodiacyl peroxide [FO2SCF2CF2OCF(CF3)CF2OCF(CF3)COO]2 1 with sodium nitrite in F113 (CClF2CCl2F) at room temperature, reacted with a series of p-substituted benzaldehydes 4 via regio-selective abstraction of the formyl hydrogen followed by spin trapping of the acyl radical intermediate 5, thus led to the formation of stable spin adducts ω-fluorosulfonylperfluoroalkyl p-substituted benzoyl nitroxides 6. The correlation analyses of aN values of nitroxides 6 with various substituent constants disclose that the polar effects are the major factors varying the spin density on the nitroxyl-nitrogen while the effect through spin-delocalization is felt slightly.