Pressure-Induced Phase Transition in Hydrogen-Bonded Supramolecular Adduct Formed by Cyanuric Acid and Melamine

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• 作者：Kai Wang ; Defang Duan ; Run Wang ; Dan Liu ; Lingyun Tang ; Tian Cui ; Bingbing Liu ; Qiliang Cui ; Jing Liu ; Bo Zou ; Guangtian Zou
• 刊名：Journal of Physical Chemistry B
• 出版年：2009
• 出版时间：November 5, 2009
• 年：2009
• 卷：113
• 期：44
• 页码：14719-14724
• 全文大小：287K
• 年卷期：v.113,no.44(November 5, 2009)
• ISSN：1520-5207

文摘

Single-crystal samples of the 1:1 adduct between cyanuric acid and melamine (CA·M), an outstanding case of noncovalent synthesis, have been studied by Raman spectroscopy and synchrotron X-ray diffraction in a diamond anvil cell up to pressures of 15 GPa. The abrupt changes in Raman spectra around 4.4 GPa have provided convincing evidence for pressure-induced structural phase transition. This phase transition was confirmed by angle dispersive X-ray diffraction (ADXRD) experiments to be a space group change from C2/m to its subgroup P2₁/m. On release of pressure, the observed transition was irreversible, and the new high-pressure phase was fully preserved at ambient conditions. We propose that this phase transition was due to supramolecular rearrangements brought about by changes in the hydrogen bonding networks.