Temperature dependence of one-dimensional hydrogen bonding in morpholinium hydrogen chloranilate studied by 35Cl nuclear quadrupole resonance and multi-temperature X-ray diffraction
Temperature dependence of one-dimensional hydrogen bonding in morpholinium hydrogen chloranilate studied by 35Cl nuclear quadrupole resonance and multi-temperature X-ray diffraction
复制标题
通过 35Cl 核四极共振和多温 X 射线衍射研究氯苯酸氢吗啉中一维氢键的温度依赖性
DOI：
10.1039/c2cp41241a
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
and Tetsuo Asaji
中科院分区：
文献类型：
--
作者：
Yasuhiro Tobu;Ryuichi Ikeda;Taka-aki Nihei;Kazuma Gotoh;Hiroyuki Ishida;and Tetsuo Asaji
35Cl NQR 频率和自旋晶格弛豫时间 T1 的温度依赖性已在 4.2–420 K 的宽温度范围内测量了氯苯酸氢吗啉，其中形成了氯苯酸氢离子的一维 O–H⋯O 氢键分子链。通过分析 NQR 频率的反常温度依赖性，推断出氢键分子链电子态的剧烈温度变化。根据 NQR 和多温度 X 射线衍射的结果讨论了 O⋯H⋯O 氢键中氢原子的分布。高于约。 330 K 时，T1 急剧下降，活化能约为 330 K。 70 kJ mol−1，同位素比 37Cl T1/35Cl T1 = 0.97 ± 0.2。电场梯度张量 z 轴的方向变化与相邻氯苯酸氢离子之间的氢转移相结合被认为是一种可能的弛豫机制。
The temperature dependence of 35Cl NQR frequencies and the spin–lattice relaxation times T1 has been measured in the wide temperature range of 4.2–420 K for morpholinium hydrogen chloranilate in which a one-dimensional O–H⋯O hydrogen-bonded molecular chain of hydrogen chloranilate ions is formed. An anomalous temperature dependence of the NQR frequencies was analyzed to deduce a drastic temperature variation of the electronic state of the hydrogen-bonded molecular chain. The hydrogen atom distribution in the O⋯H⋯O hydrogen bond is discussed from the results of NQR as well as multi-temperature X-ray diffraction. Above ca. 330 K, the T1 showed a steep decrease with an activation energy of ca. 70 kJ mol−1 and with an isotope ratio 37Cl T1/35Cl T1 = 0.97 ± 0.2. The orientational change of the z axis of electric field gradient tensor in conjunction with the hydrogen transfer between adjacent hydrogen chloranilate ions is suggested as a possible relaxation mechanism.