Exploration of the Pyrazinamide Polymorphism at High Pressure

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• 作者：Xiao Tan ; Kai Wang ; Shourui Li ; Hongsheng Yuan ; Tingting Yan ; Jing Liu ; Ke Yang ; Bingbing Liu ; Guangtian Zou ; Bo Zou
• 刊名：The Journal of Physical Chemistry B
• 出版年：2012
• 出版时间：December 13, 2012
• 年：2012
• 卷：116
• 期：49
• 页码：14441-14450
• 全文大小：789K
• 年卷期：v.116,no.49(December 13, 2012)
• ISSN：1520-5207

文摘

We report the high-pressure response of three forms (伪, 未, and 纬) of pyrazinamide (C₅H₅N₃O, PZA) by in situ Raman spectroscopy and synchrotron X-ray diffraction techniques with a pressure of about 14 GPa. These different forms are characterized by various intermolecular bonding schemes. High-pressure experimental results show that the 纬 phase undergoes phase transition to the 尾 phase at a pressure of about 4 GPa, whereas the other two forms retain their original structures at a high pressure. We propose that the stabilities of the 伪 and 未 forms upon compression are due to the special dimer connection that these forms possess. On the other hand, the 纬 form, which does not have this connection, prefers to transform to the closely related 尾 form when pressure is applied. The detailed mechanism of the phase transition together with the stability of the three polymorphs is discussed by taking molecular stacking into account.