2-Naphthoic acid at 153 K.
2-Naphthoic acid at 153 K.
复制标题
153 K 时的 2-萘甲酸。
DOI：
10.1107/s0108270196008876
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
R. E. Gerkin
中科院分区：
文献类型：
--
作者：
A. Blackburn;L. J. Fitzgerald;R. E. Gerkin
研究了2-萘甲酸C11H8O2在153K下的结构，以确定羧酸基的无序程度，并与室温结构进行了比较。对羧基-O原子各向异性位移椭球的分析表明，这些参数与O原子的热运动完全一致。具有有序的羧基-O原子的模型，但在两个位置精制的酸-H原子，每个原子的占有率为0.5，被发现在统计上显著优于具有有序的羧基-O原子和有序的酸-H原子的模型。因此，就像在室温研究中一样，最好的结构描述是O原子是有序的，而酸-H原子是无序的。尽管如此，296K和153K时羧基的几何参数的比较表明在较低的温度下朝着全有序结构的方向发展。除了预期的轻微整体收缩和羧基的几何结构略有变化外，其结构实际上与室温下相同。
The structure of 2-naphthoic acid, C11H8O2, has been investigated at 153 K in order to determine the degree of disorder of the carboxylic acid group for comparison with that of the room-temperature structure. Analysis of the anisotropic displacement ellipsoids of the carboxyl-O atoms demonstrated that these parameters are wholly consistent with thermal motion of the O atoms. A model with ordered carboxyl-O atoms, but with the acid-H atom refined at two sites with 0.5 occupancy at each, was found to be statistically significantly better than a model with ordered carboxyl-O atoms and an ordered acid-H atom. Thus, as in the room-temperature study, the best structural description is that the O atoms are ordered and the acid-H atom is disordered. Nonetheless, comparisons of the geometric parameters of the carboxyl groups at 296 and 153 K suggest progress toward a fully ordered structure at the lower temperature. Except for the expected slight overall contraction and the slightly altered geometry of the carboxyl group, the structure is virtually the same as at room temperature.