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首页> 外文期刊>Acta Crystallographica, Section B. Structural Science >Basic forms of supramolecular self-assembly organized by parallel and antiparallel hydrogen bonds in the racemic crystal structures of six disubstituted and trisubstituted cyclopentane derivatives.
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Basic forms of supramolecular self-assembly organized by parallel and antiparallel hydrogen bonds in the racemic crystal structures of six disubstituted and trisubstituted cyclopentane derivatives.

机译：由六个双取代和三取代环戊烷衍生物的外消旋晶体结构中的平行和反平行氢键组成的超分子自组装的基本形式。

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摘要

A selection of stereoisomeric 2-hydroxy-1-cyclopentanecarboxamides, a 4-tert-butyl derivative and three tert-butyl derivatives of the respective carboxylic acid were subjected to X-ray crystallography. The optically active molecules (I)--(VI) form racemic crystals. Each racemic structure is basically determined by two intermolecular hydrogen bonds of O--H...O==C--XH and O==C--X--H...OH types (X = O, NH). The partially similar patterns of close packing observed reflect five basic forms of supramolecular self-assembly. In the racemic crystals of chiral molecules, there are homo- and heterochiral chains of molecules formed by the principal (O--H...O==C) hydrogen bonds. These chains assemble either in a parallel or antiparallel mode. The parallel homochiral chains (hop) observed in structure (II), (1R*,2R*)-2-hydroxy-1-cyclopentanecarboxamide, demand the polar space group Pca2(1), while the parallel heterochiral chains (hep) are organized in antiparallel layers with space group P2(1) in structure (VI), (1R*,2S*,5R*-5-tert-butyl-2-hydroxy-1-cyclopentanecarboxylic acid). Heterochiral chains in an antiparallel array (hea) are found in (I), (1R*,2S*)-2-hydroxy-1-cyclopentanecarboxamide, and (V) [(1R*,2S*4S*)-4-tert-butyl-2-hydroxy-1-cyclopentanecarboxylic acid, space group P2(1)/c]. Structures (IV), (1R*,2S*,4R*)-4-tert-butyl-2-hydroxy-1-cyclopentanecarboxylic acid, and (III), (1R*,2R*,4S*)-4-tert-butyl-2-hydroxy-1-cyclopentanecarboxamide, reveal that homochiral chains in an antiparallel array (hoa; cross-linked by heterochiral dimers held together by the second hydrogen bonds) can be formed by either translation (space group P1) or a screw axis (space group P2(1)/c). These alternatives are denoted hoa1 and hoa2. Similarly, within each pattern (hea, hep and hop) two slightly different alternatives can be expected. The partial similarities in the identified five patterns of hydrogen bonding are described by graph-set notations. Structures (I), (IV) and (V) can be characterized by a common supramolecular synthon, while the highest degree of similarity is shown by the isostructurality of (I) and (V).
机译：对各种羧酸的各种立体异构体2-羟基-1-环戊烷甲酰胺，4-叔丁基衍生物和三种叔丁基衍生物进行X射线晶体学分析。旋光分子（I）-（VI）形成外消旋晶体。每个外消旋结构基本上由O--H ... O == C–XH和O == C--X–H ... OH类型（X = O，NH）的两个分子间氢键决定。观察到的部分相似的紧密堆积模式反映了超分子自组装的五种基本形式。在手性分子的外消旋晶体中，存在由主要（OH--O ... O == C）氢键形成的分子的同手性和杂手性链。这些链以并行或反并行模式组装。在结构（II）中观察到的平行同手性链（hop）（1R *，2R *）-2-羟基-1-环戊烷羧酰胺需要极性空间基团Pca2（1），而平行杂手性链（hep）则是有组织的在结构（VI）中具有空间基团P2（1）/ n的反平行层中，（1R *，2S *，5R * -5-叔丁基-2-羟基-1-环戊烷羧酸）。在（I），（1R *，2S *）-2-羟基-1-环戊烷羧酰胺和（V）[（1R *，2S * 4S *）-4-tert -丁基-2-羟基-1-环戊烷羧酸，空间基团P2（1）/ c]。结构（IV），（1R *，2S *，4R *）-4-叔丁基-2-羟基-1-环戊烷羧酸和（III），（1R *，2R *，4S *）-4-叔-丁基-2-羟基-1-环戊烷甲酰胺表明，反平行阵列中的同手性链（hoa;通过由第二个氢键保持在一起的杂手性二聚体交联）可以通过翻译（空间组P1）或螺钉形成轴（空间组P2（1）/ c）。这些替代方案表示为hoa1和hoa2。同样，在每个模式（hea，hep和hop）内，可以预期有两个略有不同的替代方案。通过图形集符号描述了已识别的五个氢键模式中的部分相似性。结构（I），（IV）和（V）可以通过共同的超分子合成子来表征，而最高的相似度则通过（I）和（V）的同构性来显示。

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