引用本文:
【打印本页】   【HTML】   【下载PDF全文】   View/Add Comment  【EndNote】   【RefMan】   【BibTex】
←前一篇|后一篇→ 过刊浏览    高级检索
本文已被:浏览 23次   下载 19 本文二维码信息
码上扫一扫!
分享到: 微信 更多
Infrared Spectroscopy of Neutral and Cationic Pyrrolidine Monomer in Supersonic Jet
Min Xie*, Zhao-li Zhang, Yu Zhang, Xiao-nan Sun, Fu-fei Sun, Yong-jun Hu*
MOE Key Laboratory of Laser Life Science & Guangdong Provincial Key Laboratory of Laser Life Science, Guangzhou Key Laboratory of Spectral Analysis and Functional Probes, College of Biophotonics, South China Normal University, Guangzhou 510631, China
Abstract:
Pyrrolidine, a five membered heterocyclic molecule, is widely existing in organism. Herein, infrared spectra of pyrrolidine monomer in neutral and cationic states were obtained by vacuum ultraviolet ionization, infrared photodissociation and time of flight mass spectrometry. Both in neutral and cationic states, it is found that their CH stretching vibration bands are red shifted. In the IR spectrum of neutral pyrrolidine, because the electric dipole moment of NH is small, we have not observed the NH stretching vibration bands. However, the NH stretching vibration band of pyrrolidine is greatly enhanced after ionization, and this band red-shifts compared with the previous experiment. The red shifts of CH stretching vibrations in neutral and cationic states are caused by the negative and positive hyperconjugation, respectively. The enhancement and red shift of the NH stretching band are owing to the ejection of the electrons on the N atom after ionization. Through the calculations, it is found that the acidity of the CH bond is a little stronger than that of NH bond. These kinds of studies would be helpful to understand the intrinsic properties of biomolecules in neutral and cationic states, and to provide reference for the further study of living organic macromolecules.
Key words:  IR spectroscopy, Hyperconjugation, Cationic state, CH bond acidity, Gas phase
FundProject:
超声分子束中中性态和离子态吡咯烷的红外光谱
谢 敏*, 张兆李, 张 宇, 孙晓楠, 孙福飞, 胡勇军*
华南师范大学光子学学院激光生命科学研究所,广州光谱分析与功能探针重点实验室,激光生命科学教育部重点实验室,广州 510631
摘要:
本文应用真空紫外光电离结合红外光解离以及飞行时间质谱技术获得超声分子束中吡咯烷单体在中性态和离子态的红外光谱. 研究发现,吡咯烷在中性态和离子态的CH伸缩振动均有不同程度的红移现象. 在中性态吡咯烷中,由于NH的电偶极矩较小,没有观察到NH伸缩振动峰. 而电离后的吡咯烷NH伸缩振动峰有很大的增强,并与其他实验相比出现红移现象. 通过理论计算发现中性态和离子态的CH伸缩振动的红移分别是由反超共轭和正超共轭现象引起的. 而NH峰的增强和红移则是由于N原子上的电子被电离所引起的. 通过计算分子的气态酸碱度发现,在离子态中,CH的酸性比NH的酸性略强.
关键词:  红外光谱,超共轭现象,离子态,CH键的酸性,气态
DOI:10.1063/1674-0068/cjcp1910183
分类号: