Molecular recognition and interaction between uracil and urea in solid-state studied by terahertz time-domain spectroscopy.
Using terahertz time-domain spectroscopy characterization, we observe that urea is able to recognize and interact with uracil efficiently even in the solid phase without involving water or solvents. A cocrystal configuration linked by a pair of hydrogen bonds between uracil and urea was formed. The terahertz absorption spectrum of the cocrystal shows a distinct new absorption at 0.8 THz (26.7 cm(-1)), which originates from the intermolecular hydrogen bonding. Both mechanical milling and heating can accelerate the reaction efficiently. Density functional theory was adopted to simulate the vibrational modes of the cocrystal, and the results agree well with the experimental observation. Multiple techniques, including powder X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy, were performed to investigate the reaction process, and they presented supportive evidence. This work enables in-depth understanding of recognition and interaction of urea with nucleobases and comprehension of the denaturation related to RNA. We also demonstrate that terahertz spectroscopy is an effective and alternative tool for online measurement and quality control in pharmaceutical and chemical industries.
Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences , Shanghai 201800, People's Republic of China.
Jingqi
J
Yang
Shaoxian
S
Li
Hongwei
H
Zhao
Bo
B
Song
Guoxin
G
Zhang
Jianbing
J
Zhang
Yiming
Y
Zhu
Jiaguang
J
Han
D008854:Microscopy, Electron; D015394:Molecular Structure; D009691:Nucleic Acid Denaturation; D033362:Powder Diffraction; D011789:Quantum Theory; D012313:RNA / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D055068:Terahertz Spectroscopy; D013997:Time Factors; D014498:Uracil / Q000737:chemistry*; D014508:Urea / Q000737:chemistry*
D014498:Uracil; D012313:RNA; D014508:Urea