文献类型：期刊文献

英文题名：Terahertz spectroscopy of enantiomeric and racemic pyroglutamic acid

作者：Wu, Zhipeng[1,2];Zhu, Zhongjie[2,3];Cheng, Chao[1,2];Zhang, Jianbing[2,3];Gong, Yan[4];Xu, Mingzhu[4];Li, Shaoping[1];Zhao, Hongwei[2,3]

机构：[1]East China Univ Sci & Technol, Sch Chem Engn, Shanghai 200237, Peoples R China;[2]Chinese Acad Sci, Shanghai Inst Appl Phys, Shanghai 201800, Peoples R China;[3]Chinese Acad Sci, Shanghai Adv Res Inst, Zhangjiang Lab, Shanghai 201210, Peoples R China;[4]Tarim Univ, Key Lab Modern Agr Engn, Sch Mech & Elect Engn, Alar 843300, Peoples R China

年份：2020

卷号：225

外文期刊名：SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY

收录：;EI(收录号：20194107518587);WOS:【SCI-EXPANDED(收录号:WOS:000504048200050)】；

基金：This work was supported by the Main Direction Program of Knowledge Innovation and Open Project Program of Key Laboratory of Interfacial Physics and Technology, Chinese Academy of Sciences. The National Defense Science and Technology Innovation Special Zone.

语种：英文

外文关键词：Pyroglutamic acid; Terahertz time-domain spectroscopy; Density functional theory; Intermolecular interactions; Temperature effect; Chirality

摘要：The low-frequency vibrational properties of D-, L- and DL-pyroglutamic acid (PGA) have been investigated with the terahertz time-domain spectroscopy (THz-TDS) from 05 to 4.5 THz. The enantiomers (D- and L-PGA) present similar absorption spectra, while the spectrum of racemate (DL-PGA) is obviously different. The temperature-dependent THz spectra of different PGA were recorded in the range of 293-83 K. The spectral changes during the cooling process suggest that D- and L-PGA undergo a structural phase transition, and no phase change of DL-PGA was found. The results indicate that THz spectroscopy is highly sensitive to the crystal structure of molecules. The density functional theory (DFT) calculations based on the crystal structures were performed to simulate the sample's THz spectra. It was demonstrated that the characteristic resonant absorption peaks of the enantiomeric and racemic PGA in the low-frequency THz region originate from the different vibrations, which corresponding to the specific structures and intermolecular interactions. The conformational diversity and fluctuation may help to understand the properties of PGA in biochemistry and functional material. (C) 2019 Elsevier B.V. All rights reserved.