Neutral crown-containing and model styrylheterocycles of the 4-pyridine, 4-quinoline, and 9-acridine series were synthesized under acidic catalysis. The influence of the molecular geometry of these compounds, as well as of related styrylheterocycles of the 2-benzothiazole and benzobisthiazole series, on the formation of a particular crystal packing was investigated based on X-ray diffraction data. An extension of the conjugation system in the molecules can result in the sandwich-herringbone packing motif as the only one of the three packing motifs most typical of this class of compounds. This packing provides the preorganization of the structural units for the [2+2] photocycloaddition reaction. The styrylheterocycle containing the bulky 9-acridine moiety is nonplanar due to strong intramolecular steric interactions. The packing motifs formed by nonplanar molecules do not provide the preorganization of the molecules for the [2+2] photocycloaddition. The introduction of the crown ether moiety into the benzene ring of the styrylheterocycle can decrease the predictability of the packing motif as a result of the inclusion of solvent molecules capable of hydrogen bonding with the heteroatoms of the macrocycle in the crystal structure.
合成了中性含冠和模型的4-
吡啶、4-
喹啉和9-
咔唑系列的
苯乙烯杂环化合物,采用酸催化。基于X射线衍射数据,研究了这些化合物以及相关的2-
苯并噻唑和苯并双
噻唑系列的
苯乙烯杂环的分子几何形状对特定晶体堆积的影响。分子中共轭系统的扩展可能导致三种最典型堆积形式中的唯一一种——夹心鱼骨堆积。这种堆积为[2+2]光环加成反应的结构单元提供了预组织。由于强烈的分子内立体相互作用,含有笨重的9-
咔唑单元的
苯乙烯杂环呈非平面形态。非平面分子形成的堆积形式不提供分子在[2+2]光环加成反应中的预组织。将
冠醚单元引入
苯乙烯杂环的苯环中,可能会因能够与宏环的杂原子形成氢键的溶剂分子的参与而降低堆积形式的可预测性。