Department of Chemistry, Georgetown University, Box 571227-1227, Washington, D.C. 20057, United States.
Inorg Chem. 2021 Nov 1;60(21):15968-15974. doi: 10.1021/acs.inorgchem.1c00625. Epub 2021 Jun 29.
Nitric oxide (NO) is a key signaling molecule in health and disease. While nitrite acts as a reservoir of NO activity, mechanisms for NO release require further understanding. A series of electronically varied β-diketiminatocopper(II) nitrite complexes Cu react with a range of electronically tuned triarylphosphines PAr that release NO with the formation of O═PAr. Second-order rate constants are largest for electron-poor copper(II) nitrite and electron-rich phosphine pairs. Computational analysis reveals a transition-state structure energetically matched with experimentally determined activation barriers. The production of NO follows a pathway that involves nitrite isomerization at Cu from κ-ON to κ-NO followed by O-atom transfer (OAT) to form O═PAr and [Cu]-NO that releases NO upon PAr binding at Cu to form [Cu]-PAr. These findings illustrate important mechanistic considerations involved in NO formation from nitrite via OAT.
一氧化氮（NO）是健康和疾病中一种关键的信号分子。虽然亚硝酸盐作为 NO 活性的储库，但需要进一步了解 NO 释放的机制。一系列电子变化的β-二酮亚胺合铜（II）亚硝酸盐配合物[Cu]（κ-ON）与一系列电子调谐的三芳基膦 PAr 反应，形成 O═PAr 并释放 NO。电子缺的铜（II）亚硝酸盐和电子富的膦对的二级速率常数最大。计算分析揭示了与实验确定的活化能垒能量匹配的过渡态结构。NO 的生成遵循一条途径，涉及亚硝酸盐在 Cu 上从 κ-ON 到 κ-NO 的异构化，然后进行 O-原子转移（OAT）形成 O═PAr 和 [Cu]-NO，当 PAr 在 Cu 上结合形成 [Cu]-PAr 时，NO 释放。这些发现说明了通过 OAT 从亚硝酸盐形成 NO 所涉及的重要的机制考虑。
