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首页> 外文期刊>Physical chemistry chemical physics: PCCP >Substituent effect on the interaction of aromatic primary amines and diamines with supercritical CO2 from infrared spectroscopy and quantum calculations
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Substituent effect on the interaction of aromatic primary amines and diamines with supercritical CO2 from infrared spectroscopy and quantum calculations

机译：红外光谱和量子计算中取代基对芳族伯胺和二胺与超临界二氧化碳相互作用的影响

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摘要

The nature and the strength of the interactions occurring between aromatic primary amines and CO2 have been investigated by combining infrared spectroscopy with molecular modelling. A series of infrared absorption experiments on various aromatic mono- and diamines in supercritical CO2 have been performed at constant temperature (T = 40 °C) for various CO2 pressures varying from 6 to 30 MPa. Then, we carried out a theoretical analysis based on quantum calculations using both density functional (B3LYP) and ab initio (MP2) computational methods. Whatever the amine considered, CO2 is found to be on average above the nitrogen atom of the NH2 group for which the donating lone pair interacts with the carbon atom of CO2. Several types of interactions have been identified, namely, electron donor-acceptor (EDA), hydrogen bonds as well as dispersion forces. Contrary to aliphatic amines, the dispersion interaction is significant in the aromatic amine-CO2 complexes because of the presence of the aromatic ring. The substituents are found to influence the stability and structure of the amine-CO2 complexes, directly by electrostatic and steric effects of the substituent, and indirectly through the change in the partial charge on the nitrogen atom. Finally, a good correlation has been put in evidence between the partial charge on the nitrogen atom and the EDA interaction occurring between the aromatic amines and CO2.
机译：通过结合分子光谱和红外光谱研究了芳族伯胺与二氧化碳之间相互作用的性质和强度。在恒定温度（T = 40°C）下，对于6至30 MPa不等的各种CO2压力，已对超临界CO2中的各种芳族单胺和二胺进行了一系列红外吸收实验。然后，我们基于量子计算，使用密度泛函（B3LYP）和从头算（MP2）计算方法进行了理论分析。无论考虑哪种胺，都发现CO2平均高于供体孤对与CO2碳原子相互作用的NH2基团的氮原子之上。已经确定了几种类型的相互作用，即电子给体-受体（EDA），氢键以及分散力。与脂族胺相反，由于芳环的存在，在芳族胺-CO2络合物中分散相互作用非常明显。发现取代基直接通过取代基的静电和空间效应，并通过氮原子上部分电荷的变化间接影响胺-CO 2络合物的稳定性和结构。最后，在氮原子上的部分电荷与芳族胺与CO2之间发生的EDA相互作用之间存在良好的相关性证据。

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