德国海德堡大学Mastalerz Michael团队发现弱超分子相互作用驱动巨大手性[8 + 12]亚胺立方体的二聚体和三聚体连环化。相关研究成果发表在2022年12月1日出版的《自然—化学》。

机械联锁的结构，如链烷和轮烷，是令人着迷的合成目标，一些用于分子开关和机器。目前，绝大多数链状结构是建立在大环上的，只有极少数三维形状持久性有机笼形成这种结构的例子被报道。然而，在所有这些情况下，连接都是基于在特定反应条件下热力学倾向的π–π堆叠。

该文中，研究表明，在合成手性[8+12]亚胺立方体的过程中，通过向前体之一添加甲氧基或硫甲基，可以诱导连环烷的形成，从而形成二聚体和三聚体连环有机笼。为了阐明潜在的驱动力，研究人员在各种条件下使11种不同的1,4-二取代对苯二甲醛与手性三氨基三苯并三喹啉反应，以研究单体笼或链状笼二聚体是优选的产物。研究发现，连接主要是由取代基产生的弱相互作用而不是由π-堆叠引导的。

附：英文原文

Title: Dimeric and trimeric catenation of giant chiral [8 + 12] imine cubes driven by weak supramolecular interactions

Author: Benke, Bahiru Punja, Kirschbaum, Tobias, Graf, Jrgen, Gross, Jrgen H., Mastalerz, Michael

Issue&Volume: 2022-12-01

Abstract: Mechanically interlocked structures, such as catenanes and rotaxanes, are fascinating synthetic targets and some are used for molecular switches and machines. Today, the vast majority of catenated structures are built upon macrocycles and only a very few examples of three-dimensional shape-persistent organic cages forming such structures have been reported. However, the catenation in all these cases was based on a thermodynamically favoured π–π-stacking under certain reaction conditions. Here, we show that catenane formation can be induced by adding methoxy or thiomethyl groups to one of the precursors during the synthesis of chiral [8+12] imine cubes, giving dimeric and trimeric catenated organic cages. To elucidate the underlying driving forces, we reacted 11 differently 1,4-disubstituted terephthaldehydes with a chiral triamino tribenzotriquinacene under various conditions to study whether monomeric cages or catenated cage dimers are the preferred products. We find that catenation is mainly directed by weak interactions derived from the substituents rather than by π-stacking.

DOI: 10.1038/s41557-022-01094-w

Source: https://www.nature.com/articles/s41557-022-01094-w