Crystal structures of the salts of chiral primary amines with achiral carboxylic acids: Recognition of the commonly-occurring supramolecular assemblies of hydrogen-bond networks and their role in the formation of conglomerates
Crystal structures of the salts of chiral primary amines with achiral carboxylic acids: Recognition of the commonly-occurring supramolecular assemblies of hydrogen-bond networks and their role in the formation of conglomerates
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DOI：
10.1021/ja9539960
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发表时间：
1996-04-10
影响因子：
15
通讯作者：
Saigo, K
中科院分区：
文献类型：
--
作者：
Kinbara, K;Hashimoto, Y;Saigo, K
对手性伯胺与非手性一元羧酸的7种聚合体、17种外消旋化合物和4种对映体纯盐进行了x射线晶体学研究。砾岩盐的晶体结构表明，这些晶体可以看作是一个典型的柱状氢键网络的组合，其中铵离子和羧酸阴离子围绕2倍螺旋轴排列。另一方面，外消旋化合物盐的晶体结构大致可分为两类。一种是由2(1)柱组成的晶体；另一种类型是由不同类型的柱状氢键网络组成的晶体，其中铵离子和羧酸阴离子通过反转中心（i柱）连接。研究结果表明，2(1)柱的形成和组装在这些盐的砾岩形成过程中是必不可少的，砾岩盐和外消旋化合物盐之间2(1)柱堆积的差异是由2(1)柱之间的范德华相互作用决定的。
X-ray crystallographic studies were carried out for seven conglomerates, seventeen racemic compounds, and four enantiomerically pure salts of chiral primary amines with achiral monocarboxylic acids. The crystal structures of the conglomerate salts revealed that these crystals can be regarded as being an assembly of a characteristic columnar hydrogen-bond network in which the ammonium cations and the carboxylate anions are aligned around a 2-fold screw axis (2(1)-column). On the other hand, the crystal structures of the racemic-compound salts could be broadly classified into two types. One type is a crystal consisting of 2(1)-columns; the other type is a crystal consisting of a different type of columnar hydrogen-bond network in which the ammonium cations and the carboxylate anions are related by inversion centers (i-column). Our results suggest that both the formation and the assembly of 2(1)-columns are essential in the formation of conglomerates from these salts, and that the difference in the packing of 2(1)-columns between conglomerate salts and racemic-compound salts is governed by van der Waals interaction between the 2(1)-columns.