GAS PHASE CHEMISTRY OF PEROXYNITRITE

过氧亚硝酸盐的气相化学

• 批准号: 2655608
• 负责人: WILLIAM A PRYOR
• 金额: $ 2.31万
• 依托单位: LOUISIANA STATE UNIV A&M COL BATON ROUGE
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-02-01 至 2000-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2655608
• 关键词: anions; chemical reaction; chemical synthesis; gas; interferometry; mass spectrometry; nitrites; quantum chemistry; superoxides

DESCRIPTION Peroxynitrite is formed physiologically from the reaction of superoxide radical anion (O2-) and nitric oxide neutral radical (NO). Both radicals are produced by activated macrophages and neutrophils. Peroxynitrite is not stable and isomerizes to nitrate. Both peroxynitrite and peroxynitrous acid (pKa = 6.8) are oxidants. These oxidants are very reactive with functional groups present in biomolecules and may cause significant and continuous damage to biomolecules in vivo since superoxide is continuously produced both intentionally and as an unwanted by-product of normal oxidative metabolism and nitric oxide, recently discovered to be a new type of neurotransmitter, is continuously present in vivo. Work in the lab of the U.S. P.I. is focused on studying the solution phase reactions of peroxynitrite and peroxynitrous acid under physiological types of conditions. Significant progress has already been made in this research, such as the discovery that peroxynitrous acid can oxidize methionine by at least two different mechanisms, a direct bimolecular reaction and one-electron multi-step electron transfer radical process. These significant studies probably only scratch the surface of the mechanistic complexity involved in oxidation reactions performed by peroxynitrous acid. One important observation is that in the course of the isomerization of peroxynitrous acid to nitric acid an unstable intermediate is formed which is a very strong oxidant. Although work in the Pryor lab will be able to characterize the pattern of reactivity of this intermediate, it is too unstable to be observed directly for structure determination. The proposed gas phase and theoretical work in the lab of Klasinc is designed to examine the isomerization of peroxynitrous acid to nitric acid, to gain some insight into possible structures for the unstable intermediate and to assess the role of solvation, especially the possible covalent intervention of water molecules in the mechanism. The specific aims of the FIRCA are: (1) synthesize peroxynitrite in the gas phase and study its gas phase properties, (2) determine the structure and properties of ONOOH, ONOO, and ONOO with sophisticated quantum chemical calculations within and beyond the Hartree-Fock limit, (3) model quantum chemically the formation and decomposition of ONOOH, ONOO, and ONOO from various reactions in the gas phase, and (4) model quantum chemically the isomerization of ONOOH.

描述 过氧亚硝酸盐是由超氧化物的反应从生理形成的 自由基阴离子（O2-）和一氧化氮中性自由基（NO）。 两个激进分子 由活化的巨噬细胞和中性粒细胞产生。 过氧亚硝酸盐不是 稳定并异构化硝酸盐。 过氧亚硝酸盐和过氧亚硝酸都 （PKA = 6.8）是氧化剂。 这些氧化剂具有功能非常反应性 生物分子中存在的组，可能会引起重要且连续的 由于超氧化物是连续产生的，因此体内生物分子的损害 有意和作为正常氧化的不需要的副产品 代谢和一氧化氮，最近被发现是一种新型 神经递质在体内不断存在。 在美国P.I.实验室工作专注于研究溶液阶段 在生理类型下的过氧亚硝酸盐和过氧亚硝酸的反应 条件。 这项研究已经取得了重大进展， 例如，发现过氧亚酸可以通过AT氧化蛋氨酸的发现 至少两种不同的机制，一种直接的双分子反应和 单电子多步电子转移自由基过程。 这些 重要的研究可能仅刮擦机械的表面 通过过氧亚硝酸进行的氧化反应涉及的复杂性。 一个重要的观察结果是，在异构化过程中 过氧亚酸到硝酸，形成了不稳定的中间体 是一种非常强的氧化剂。 尽管Pryor Lab的工作将能够 表征该中间体的反应性模式，也是如此 无法直接观察到结构确定。 Klasinc实验室中提出的气相和理论工作是 旨在检查过氧亚硝酸与硝酸的异构化， 为了了解不稳定中级的可能结构 并评估溶剂化的作用，尤其是可能的共价 水分子在机制中的干预。 特定目标 FIRCA是：（1）在气相中合成过氧亚硝酸盐并研究其气体 相位特性，（2）确定onooh，onoo， 并具有复杂的量子化学计算和更高的量子化学计算 Hartree-fock极限，（3）化学量子量子的形成和 onooh，onoo和onoo的分解来自气体中各种反应 相位，（4）量子对Onooh的异构化进行量子模型。