摘要
利用太赫兹时域光谱(Terahertz time-domain spectroscopy,THz-TDS)技术对呋喃妥因、尿素及其研磨和溶剂共晶体进行表征分析,实验结果显示了呋喃妥因和尿素的研磨和溶剂共晶体位于0.85、1.23、1.60 THz的吸收峰明显区别于原料物质.该结果表明太赫兹光谱技术可以有效鉴别呋喃妥因、尿素及其共晶体.运用密度泛函理论(Density functional theory,DFT)对呋喃妥因和尿素共晶体的2种可能结构进行了结构优化和光谱模拟,模拟结果显示其中的结构A在0.49、0.81、1.25、1.61 THz处具有吸收峰,与实验结果较吻合.推断共晶体氢键的形成位置为尿素中的氨基H6和呋喃妥因上的酰胺基O30,该处形成第一处氢键,而呋喃妥因的酰胺基H31和尿素上的羰基O1形成第二处氢键.同时结合理论模拟结果对呋喃妥因和尿素共晶体分子振动模式进行归属.
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 030 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.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2015年第10期1069-1073,共5页
Acta Chimica Sinica
基金
国家自然科学基金(No.21205110)
浙江省自然科学基金(No.LY15B050004)资助~~
关键词
呋喃妥因
尿素
共晶体
氢键
太赫兹时域光谱
nitrofurantion
urea
co-crystal
hydrogen bond
Terahertz time-domain spectroscopy
