Elucidation of Crystallization Process and Crystal Engineering of Conglomerates

已知由手性胺和非手性羧酸组成的一些盐结晶成聚集体。该项目旨在阐明该因素并建立外消旋体转化为砾岩晶体的指导方针。通过对大量伯羧酸铵晶体结构的分析，试图提取砾岩晶体的结构特征。结果，对于大部分的盐晶体，酸和胺组分形成由氢键构成的柱，并且晶体由这些柱制成。圆柱体可分为两类，一类是以双螺旋轴为特征，另一类是以中心对称为特征。在砾岩盐的情况下，只有前者是可能的，而这两种类型的柱在非手性盐或外消旋化合物盐中以竞争的概率存在。当外消旋体形成中心对称柱时，盐可能是外消旋化合物。相反，当一个无规晶体形成螺旋柱时，可以通过聚集具有相同手性的柱来形成聚集体。然而，即使在这种情况下，通过以1：1的比例聚集对映体柱，外消旋化合物也是可能的。这两种类型的结构可以在外消旋化合物盐中以竞争的概率看到。影响这两种类型的包装之间的势能的因素是柱的形状和货车的范德华势，并将估计通过计算方法，如分子mechanism.The的主要因素，形成的砾岩晶体的衍生化的手性胺与非手性羧酸的盐，可以归因于形成的光学活性，螺旋柱。用计算方法估计砾岩晶体的形成是一个很有前景的课题。

It is known that a few salts consisting of a chiral amine and an achiral carboxylic acid crystallize into conglomerates. This project aimed to elucidate the factor and to establish a guideline for converting racemates into conglomerate crystals. By means of crystal structural analysis of a large number of primary ammonium carboxylates, we tried to extract the characteristic structural feature of conglomerate crystals. As a result, for the most part of the salt crystals, acid and amine components make a column constructed by hydrogen bonds, and the crystals were made up from these columns. The column could be classified into two categories ; one is characterized by a two-fold screw axis and others by centrosymmetry. In the case of conglomerate salts, only the former is possible, while the two types of columns exist in a competitive probability in achiral salts or racemic compound salts. When a racemate formed centrosymmetric columns, the salt could be a racemic compound. In contrast, when a racemate formed helical columns, a conglomerate can be formed by gathering the columns having the same chirality. However, a racemic compound is also possible even in this case by gathering the enantiomeric columns in 1 : 1 ratio. These two types of structures can be seen in racemic compound salts in a competitive probability. The factors influencing the potential energies between these two types of packing are the shape of column and van der Waals potential, and would be estimated by computational methodology such as molecular mechanics.The primary factor for the formation of a conglomerate crystal by derivatization of a chiral amine to a salt with an achiral carboxylic acid could be attributable to the formation of optically active, helical column. The estimation for the formation of a conglomerate crystal with computational methodology is a prospective subject.