R=H:2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide(PTIO)/
2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl(PTI)
R=COO-Na+: carboxy-PTIO/PTI
R=N(CH3)+Cl-: trimethylammonio-PTIO/PTI

4-phenyl-2,2,5,5-tetramethylimidazoline-1-oxyl


PTIOs　＋　・NO　→　PTIs　＋　・ＮＯ2　　　　　　　　　　(1)