Superoxide radical anion adduct of 5,5-dimethyl-1-pyrroline N-oxide (DMPO). 2. The thermodynamics of decay and EPR spectral properties.
Superoxide radical anion adduct of 5,5-dimethyl-1-pyrroline N-oxide (DMPO). 2. The thermodynamics of decay and EPR spectral properties.
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DOI：
10.1021/jp0524330
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发表时间：
2005-06
期刊：
影响因子：
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通讯作者：
F. Villamena;John K. Merle;C. Hadad;J. Zweier
中科院分区：
文献类型：
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作者：
F. Villamena;John K. Merle;C. Hadad;J. Zweier
通过电子顺磁共振（EPR）光谱检测硝酮5，5-二甲基-1-吡咯啉N-氧化物（DMPO）的超氧阴离子自由基（O2*-）加合物的形成是化学和生物系统中O2*-检测的最常见技术之一。然而，DMPO-O2 H的性质多年来一直困扰着自旋捕获研究人员，因为迄今为止还没有独立合成的DMPO-O2 H。使用密度泛函理论（DFT）方法预测DMPO-O2 H的N，β-H和γ-H核的各向同性超精细耦合常数，使用与水分子的显式相互作用以及通过采用极化连续模型（PCM）的体介电效应。DMPO-O2 H衰变热力学的理论计算表明，有利的分子内重排形成亚硝基醛和羟基自由基作为产品，与实验观察一致。还计算了DMPO-O_2 H和DMPO-OH双分子分解的一些途径。
The formation of the superoxide radical anion (O2*-) adduct of the nitrone 5,5-dimethyl-1-pyrroline N-oxide (DMPO) as detected by electron paramagnetic resonance (EPR) spectroscopy is one of the most common techniques for O2*- detection in chemical and biological systems. However, the nature of DMPO-O2H has confounded spin-trapping investigators over the years, since there has been no independently synthesized DMPO-O2H to date. A density functional theory (DFT) approach was used to predict the isotropic hyperfine coupling constants arising from the N, beta-H, and gamma-H nuclei of DMPO-O2H using explicit interactions with water molecules as well as via a bulk dielectric effect employing the polarizable continuum model (PCM). Theoretical calculation on the thermodynamics of DMPO-O2H decay shows favorable intramolecular rearrangement to form a nitrosoaldehyde and a hydroxyl radical as products, consistent with experimental observations. Some pathways for the bimolecular decomposition of DMPO-O2H and DMPO-OH have also been computed.