State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
University of the Chinese Academy of Sciences, Beijing 100049, China.
Molecules. 2019 Mar 1;24(5):869. doi: 10.3390/molecules24050869.
Intermediates lie at the center of chemical reaction mechanisms. However, detecting intermediates in an organic reaction and understanding its role in reaction mechanisms remains a big challenge. In this paper, we used the theoretical calculations to explore the potential of the electron-vibration-vibration two-dimensional infrared (EVV-2DIR) spectroscopy in detecting the intermediates in the oxidation reactions of enamines and tautomerizable imines with 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO). We show that while it is difficult to identify the intermediates from their infrared and Raman signals, the simulated EVV-2DIR spectra of these intermediates have well resolved spectral features, which are absent in the signals of reactants and products. These characteristic spectral signatures can, therefore, be used to reveal the reaction mechanism as well as monitor the reaction progress. Our work suggests the potential strength of EVV-2DIR technique in studying the molecular mechanism of organic reactions in general.
中间体处于化学反应机制的中心。然而，在有机反应中检测中间体并理解其在反应机制中的作用仍然是一个巨大的挑战。在本文中，我们使用理论计算来探索电子-振动-振动二维红外（EVV-2DIR）光谱在检测烯胺和互变异构亚胺与 2,2,6,6-四甲基哌啶-1-氧自由基（TEMPO）的氧化反应中间体中的潜力。我们表明，虽然从它们的红外和拉曼信号中很难识别中间体，但这些中间体的模拟 EVV-2DIR 光谱具有良好分辨的光谱特征，而反应物和产物的信号中则没有这些特征。因此，这些特征光谱特征可用于揭示反应机制以及监测反应进程。我们的工作表明 EVV-2DIR 技术在研究一般有机反应的分子机制方面具有潜在的优势。
