AbstractThe supramolecular recognition of anions is increasingly harnessed to achieve the self‐assembly of supramolecular architectures, ranging from cages and polymers to (pseudo)rotaxanes. The cyanostar (CS) macrocycle has previously been shown to form 2 : 1 complexes with organophosphate anions that can be turned into [3]rotaxanes by stoppering. Here we achieved steric control over the assembly of pseudorotaxanes comprising the cyanostar macrocycle and a thread that is based, for the first time, on organo‐pyrophosphonates. Subtle differences in steric bulk on the threads allowed formation of either [3]pseudorotaxanes or [2]pseudorotaxanes. We demonstrate that the threading kinetics are governed by the steric demand of the organo‐pyrophosphonates and in one case, slows down to the timescale of minutes. Calculations show that the dianions are sterically offset inside the macrocycles. Our findings broaden the scope of cyanostar‐anion assemblies and may have relevance for the design of molecular machines whose directionality is a result of relatively slow slipping.
摘要阴离子的超分子识别越来越多地被用于实现超分子结构的自组装,从笼状结构、聚合物到(伪)轮烷。此前已有研究表明,
氰星(CS)大环与有机
磷酸酯形成 2 :1 的复合物,这些复合物可以通过堵塞变成 [3]rotaxanes 。在这里,我们首次实现了对由蓝星大环和基于有机-
焦磷酸盐的线组成的假轮烷组装的立体控制。螺纹上立体体积的细微差别使得[3]赝轴烷或[2]赝轴烷得以形成。我们证明,穿线动力学受有机-
焦磷酸盐的立体需求支配,在一种情况下,穿线速度会减慢到几分钟。计算结果表明,二离子在大环内部发生了立体偏移。我们的发现拓宽了青柱-阴离子组装的范围,并可能对设计其方向性是相对缓慢滑动结果的分子机器有意义。