Although mechanically interlocked molecules (MIMs) display unique properties and functions associated with their intricate connectivity, limited assembly strategies are available for their synthesis. Herein, we presented a synergistic assembly strategy based on coordination and noncovalent interactions (π–π stacking and CH⋯π interactions) to selectively synthesize molecular closed three-link chains ( 6 1 3 links), highly entangled figure-eight knots ( 4 1 knots), trefoil knot ( 3 1 knot), and Borromean ring ( 6 2 3 link). 6 1 3 links can be created by the strategic assembly of nonlinear multicurved ligands incorporating a furan or phenyl group with the long binuclear half-sandwich organometallic Cp*Rh III (Cp* = η 5 -pentamethylcyclopentadienyl) clip. However, utilizing much shorter binuclear Cp*Rh III units for union with the 2,6-naphthyl-containing ligand led to a 4 1 knot because of the increased π–π stacking interactions between four consecutive stacked layers and CH⋯π interactions. Weakening such π–π stacking interactions resulted in a 3 1 knot. The universality of this synergistic assembly strategy for building 4 1 knots was verified by utilizing a 1,5-naphthyl-containing ligand. Quantitative conversion between the 4 1 knot and the simple macrocycle species was accomplished by adjusting the concentrations monitored by NMR spectroscopy and electrospray ionization mass spectrometry (ESI-MS). Furthermore, increasing the stiff π-conjugated area of the binuclear unit afforded molecular Borromean ring, and this topology is a topological isomer of the 6 1 3 link. These artificial metalla-links and metalla-knots were confirmed by single-crystal X-ray diffraction, NMR and ESI-MS. The results offer a potent strategy for building higher-order MIMs and emphasize the critical role that noncovalent interactions play in creating sophisticated topologies.

中文翻译：

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通过配位和非共价相互作用共同驱动分子金属连接 (613, 623) 和金属结 (41, 31) 的组装


尽管机械互锁分子（MIM）显示出与其复杂连接相关的独特性质和功能，但可用于其合成的组装策略有限。在此，我们提出了一种基于配位和非共价相互作用（π-π堆积和CH⋯π相互作用）的协同组装策略，以选择性合成分子闭合三链接链（6 1 3链接）、高度纠缠的八字结（4 1结）、三叶结（3 1 结）和博罗梅安环（6 2 3 环）。 6 1 3 连接可以通过包含呋喃或苯基的非线性多曲线配体与长双核半夹心有机金属 Cp*Rh III (Cp* = η 5 -五甲基环戊二烯基) 夹的战略组装来创建。然而，利用更短的双核 Cp*Rh III 单元与含 2,6-萘基的配体结合会导致 4 1 结，因为四个连续堆叠层之间的 π-π 堆叠相互作用和 CH⋯π 相互作用增加。减弱这种 π-π 堆积相互作用会导致 3 1 结。通过利用含 1,5-萘基的配体验证了这种构建 4 1 结的协同组装策略的普遍性。 4 1 结和简单大环物质之间的定量转化是通过调整 NMR 光谱和电喷雾电离质谱 (ESI-MS) 监测的浓度来完成的。此外，增加双核单元的刚性π共轭面积提供了分子Borromean环，并且该拓扑是6 1 3链接的拓扑异构体。这些人工金属链接和金属结通过单晶X射线衍射、NMR和ESI-MS得到证实。 研究结果为构建高阶 MIM 提供了一种有效的策略，并强调了非共价相互作用在创建复杂拓扑中的关键作用。