Acta Chim. Sinica ›› 2015, Vol. 73 ›› Issue (10): 1069-1073.DOI: 10.6023/A15050351 Previous Articles     Next Articles



张琪, 方虹霞, 张慧丽, 秦丹, 洪治, 杜勇   

  1. 中国计量学院太赫兹技术与应用研究所 杭州 310018
  • 投稿日期:2015-05-22 发布日期:2015-08-18
  • 通讯作者: 杜勇
  • 基金资助:


Co-crystal between Nitrofurantion and Urea Investigated by Terahertz Spectroscopy and Density Functional Theory

Zhang Qi, Fang Hongxia, Zhang Huili, Qin Dan, Hong Zhi, Du Yong   

  1. Centre for Terahertz Research, China Jiliang University, Hangzhou 310018
  • Received:2015-05-22 Published:2015-08-18
  • Supported by:

    Project supported by the National Natural Science Foundation of China (No. 21205110) and Natural Science Foundation of Zhejiang Province (No. LY15B050004)

Terahertz time-domain spectroscopy (THz-TDS) technology was utilized for the characterization and analysis of nitrofurantion, urea, and their solvent/grinding co-crystals. Experimental results showed that similar absorption peaks of its solvent and grinding co-crystals which formed by nitrofurantion and urea at 0.85, 1.23 and 1.60 THz can be observed, indicating that they are same materials. The position and intensity of absorption peaks for such co-crystals are significantly different from corresponding original materials. The result demonstrated that THz-TDS technique could effectively identify and characterize nitrofurantion, urea and its co-crystal. The optimized geometries and vibrational spectra of the two feasible theoretical molecular structures of nitrofurantion-urea co-crystal were performed with the density functional theory (DFT) calculation. Geometry optimization was obtained by choosing B3LYP density functional with the atom-centered Gaussian-type 6-31G (d, p) basis set. The theoretical result showed that absorption peaks at 0.49, 0.81, 1.25, 1.61 THz occurred in structure A, which is pretty agreement with the THz experimental result. Comparing the experimental and theoretical results, it is confirmed that the first hydrogen bond is formed at place between amino H6 of urea and amide O30 of nitrofurantion, while the second one is constituted by amide H31 of nitrofurantion and carbonyl O1 of urea. The vibrational modes of nitrofurantion-urea co-crystal were also assigned with the help of the simulated DFT results. The different vibrational mode assignment for nitrofurantion-urea co-crystal indicates that the main vibrational features of such co-crystal lie on the ring and group out-of-plane bending vibrations in THz region. This work provides experimental and theoretical benchmark to detect and analyze the hydrogen bonding interaction and molecular structure of co-crystals in the pharmaceutical field with the newly developing terahertz spectroscopic technology.

Key words: nitrofurantion, urea, co-crystal, hydrogen bond, Terahertz time-domain spectroscopy