在超分子化学领域中,有机金属超分子大环笼的受控合成仍然是有趣且具有挑战性的工作。这里,设计并合成了两个四核矩形大环和一个八核笼,利用刚性和功能化的柱状连接体,2,6-双(吡啶-4-基)-1,7-二氢苯并[1,2-d:4,5-d']二咪唑(BBI4PY)基于三个具有不同尺寸的半夹心铑积木。X射线晶体学结合1HNMR光谱阐明了具有较短间隔物的两个结构单元仅产生矩形大环。然而,避免两个配体BBI4PY之间的π-π堆叠相互作用的较大尺寸的构造块导致八核笼形络合物的形成。后者包含两种类型的金属离子,即Rh3+和Cu2+,表现出异质金属组装化合物的显著特征。此外,笼子容纳两个游离的异丙醚溶剂分子,从而显示主机-来宾行为。
The controlled synthesis of organometallic supramolecular macrocycles cages remains interesting and challenging work in the field of supramolecular chemistry. Here, two tetranuclear rectangular macrocycles and an octuclear cage were designed and synthesized utilizing a rigid and functionalized pillar linker, 2,6-bis(pyridin-4-yl)-1,7-dihydrobenzo [1,2-d:4,5-d\']diimidazole (BBI4PY) based on three half-sandwich rhodium building blocks bearing different sizes. X-ray crystallography in combination with 1H NMR spectroscopy elucidated that the two building blocks with shorter spacers only result in rectangular macrocycles. However, the building block of bulkier size to avoid the π-π stacking interactions between two ligands BBI4PY led to the formation of an octuclear cage complex. The latter cage contains two types of metal ions, namely Rh3+ and Cu2+, showing significant characteristics of heterogeneous metal-assembling compounds. In addition, the cage accommodates two free isopropyl ether solvent molecules, thus displaying host-guest behavior.