Redetermination of the structures of 1-naphthoic acid and 2-naphthoic acid.
Redetermination of the structures of 1-naphthoic acid and 2-naphthoic acid.
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1-萘甲酸和2-萘甲酸结构的重新测定。
DOI：
10.1107/s0108270193002641
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
R. E. Gerkin
中科院分区：
文献类型：
--
作者：
L. J. Fitzgerald;R. E. Gerkin
对1-萘酸和2-萘酸的结构进行了研究，以确定羧基的无序程度。1-萘酸的键长分别为1.214(3)和1.312 (3)A， C—C—O键角分别为124.8(2)和114.2(2)度，是完全有序的。2-萘酸的C—C—O键长分别为1.256(3)和1.274 (3)a， C—C—O键角分别为117.7(2)和119.1(2)度，具有明显的无序性。在2-萘酸中，酸性H原子在两个位置被精炼，每个位置占有0.5个。对酸性O原子各向异性位移椭球体的分析表明，这些参数与O原子的热运动一致。结果表明，在2-萘酸的羧基上，质子而不是O原子是无序的。在每一种结构中，酸分子围绕反转中心形成环状二聚体，具有O…1-萘酸和2-萘酸的O（受体）距离分别为2.653(3)和2.618 (3)A。环状二聚体在每一种结构中形成层，其中靠近酸性O原子的横向分子间途径来自环H原子。2-环烷酸结构中两个O原子的分子间和分子内的接近距离和接近角度是非常均匀的。（摘要删节250字）
The structures of 1-naphthoic acid and 2-naphthoic acid have been investigated in order to determine the degree of disorder of the carboxylic acid groups. 1-Naphthoic acid was found to be completely ordered with C--O bond lengths of 1.214 (3) and 1.312 (3) A, and C--C--O bond angles of 124.8 (2) and 114.2 (2) degrees. 2-Naphthoic acid was found to possess a significant degree of disorder with C--O bond lengths of 1.256 (3) and 1.274 (3) A, and C--C--O bond angles of 117.7 (2) and 119.1 (2) degrees. In 2-naphthoic acid, the acid H atom was refined at two sites with 0.5 occupancy at each. Analysis of the anisotropic displacement ellipsoids of the acid O atoms for each structure demonstrated that these parameters are consistent with thermal motion of the O atoms. These results indicated that the proton, but not the O atoms, is disordered in the carboxylic acid group of 2-naphthoic acid. In each structure, the acid molecules form cyclic dimers about inversion centers, with an O...O(acceptor) distance of 2.653 (3) in 1-naphthoic acid and 2.618 (3) A in 2-naphthoic acid. The cyclic dimers form layers in each of these structures wherein lateral closest intermolecular approaches to the acid O atoms are from ring H atoms. The intermolecular O...H close approaches, together with the intramolecular close approaches, are very uniform in distance and angle of approach for the two O atoms in the 2-naphthoic acid structure.(ABSTRACT TRUNCATED AT 250 WORDS)