Infrared Spectra of Monohydrogenated Aniline, ortho- and para-HC6H5NH2, Generated in Solid para-Hydrogen
Infrared Spectra of Monohydrogenated Aniline, ortho- and para-HC6H5NH2, Generated in Solid para-Hydrogen
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在固体对氢中生成的一氢化苯胺、邻位和对位 HC6H5NH2 的红外光谱
DOI：
10.1021/acs.jpca.0c06079
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Lee Yuan-Pern
中科院分区：
文献类型：
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作者：
Tsuge Masashi;Chen Yu-Hsuan;Lee Yuan-Pern
单氢化苯胺（HC 6 H5 NH 2）的异构体被认为是苯胺还原反应中的重要中间体，但它们的光谱鉴定仅限于金刚烷基质中的电子顺磁共振。本文报道了HC_6H_5NH_2的两种能量最低的异构体的红外光谱，它们是在3.2K下，在苯胺和仲氢的基体沉积过程中电子轰击产生的。HC 6 H5 NH 2的红外线的强度增加，在黑暗中的电子轰击矩阵的维护期间，因为质子化的苯胺，H+ C6 H5 NH 2，被捕获的电子和苯胺和未反应的氢原子之间的进一步反应，在电子轰击过程中产生的中和延长的时间。观察到的线进行分组，根据其行为的二次光解与光在520，465，和375 nm。通过比较HC_6H_5NH_2的四种可能异构体的实验光谱和量子化学预测光谱，发现其中一组谱线归属于最稳定的ortho-HC_6 H_5 NH_2，另一组谱线归属于第二稳定的para-HC_6 H_5 NH_2。它们在不同波长下的光解行为与预测的紫外吸收带一致。根据半定量分析讨论了这些异构体的形成机理。
The isomers of monohydrogenated aniline (HC6H5NH2) are regarded as important intermediates in reduction reactions of aniline, but their spectral identification has been limited to electron paramagnetic resonance in an adamantane matrix. We report here infrared (IR) spectra of two least-energy isomers of HC6H5NH2, produced on electron bombardment during the deposition of a matrix of aniline andpara-hydrogen at 3.2 K. The intensities of IR lines of HC6H5NH2increased during maintenance of the electron-bombarded matrix in darkness for a prolonged period because of the neutralization of protonated aniline, H+C6H5NH2, by trapped electrons and further reactions between aniline and the unreacted hydrogen atoms that were produced during electron bombardment. The observed lines were grouped according to their behaviors on secondary photolysis with light at 520, 465, and 375 nm. On comparison of experimental spectra with quantum chemically predicted spectra for four possible isomers of HC6H5NH2, lines in one group were assigned to the most stableortho-HC6H5NH2and those in the other group were assigned to the secondmost stablepara-HC6H5NH2. Their photolytic behaviors at varied wavelengths are consistent with predicted ultraviolet absorption bands. The mechanisms of formation of these isomers are discussed according to semiquantitative analysis.