NMR spin trapping: detection of free radical reactions with a new fluorinated DMPO analog.
NMR spin trapping: detection of free radical reactions with a new fluorinated DMPO analog.
复制标题
NMR 自旋捕获：使用新型氟化 DMPO 类似物检测自由基反应。
DOI：
10.1016/s0891-5849(01)00505-6
复制
发表时间：
2001
影响因子：
7.4
通讯作者：
Clanton,TL
中科院分区：
文献类型：
--
作者：
Khramtsov,VV;Reznikov,VA;Berliner,LJ;Litkin,AK;Grigor'ev,IA;Clanton,TL
电子自旋共振 (ESR) 和核磁共振 (NMR) 自旋捕获用于利用 DMPO 的新型氟化类似物 4-羟基-5,5-二甲基-2-三氟甲基吡咯啉-1-氧化物 (FDMPO) 检测自由基反应。母体FDMPO自旋陷阱在-66.0 ppm处表现出单一19 F-NMR共振。与含磷自旋陷阱DEPMPO的31P-NMR灵敏度相比，信噪比提高了10.4倍。对 FDMPO 与 OH、CH3 和 CH2OH 的自旋加合物进行了表征。 FDMPO 与 DMPO 的竞争性自旋捕获表明，两者具有相似的 OH 和 C 中心自由基的加成速率。 FDMPO 相应的顺磁自旋加合物对降解极其稳定。在抗坏血酸存在下，来自以C为中心的自由基的反应产物导致在-78.6和-80ppm处(对于FDMPO/CH 3 )以及在-74.6和-76.75ppm(对于FDMPO/CH 2 OH)出现两个额外的 19 F-NMR信号。在每种情况下，这些峰都归属于它们各自的还原羟胺的两种立体异构体。 FDMPO/CH 3 羟胺的鉴定通过独立合成样品的EPR和19 F-NMR谱证实。总之，FDMPO 的自旋加合物对于 ESR 高度稳定。对于 NMR 自旋捕获，与 DEPMPO 相比，FDMPO 显示出更高的信噪比和相似的自旋捕获效率。
Electron spin resonance (ESR) and nuclear magnetic resonance (NMR) spin trapping were used for detection of free radical reactions utilizing a new fluorinated analog of DMPO, 4-hydroxy-5,5-dimethyl-2-trifluoromethylpyrroline-1-oxide (FDMPO). The parent FDMPO spin trap exhibits a single19F-NMR resonance at −66.0 ppm. The signal to noise ratio improved 10.4-fold compared to31P-NMR sensitivity of the phosphorus-containing spin trap, DEPMPO. The spin adducts of FDMPO with OH, CH3, and CH2OH were characterized. Competitive spin trapping of FDMPO with DMPO showed that both have similar rates of addition of OH and C-centered radicals. The corresponding paramagnetic spin adducts of FDMPO were extremely stable to degradation. In the presence of ascorbate, reaction products from C-centered radicals resulted in the appearance of two additional19F-NMR signals at −78.6 and −80 ppm for FDMPO/CH3and at −74.6 and −76.75 ppm for FDMPO/CH2OH. In each case, these peaks were assigned to the two stereoisomers of their respective, reduced hydroxylamines. The identification of the hydroxylamines for FDMPO/CH3was confirmed by EPR and19F-NMR spectra of independently synthesized samples. In summary, spin adducts of FDMPO were highly stable for ESR. For NMR spin trapping, FDMPO showed improved signal to noise and similar spin trapping efficiency compared to DEPMPO.