The simultaneous synthesis of a molecular nine-crossing composite knot that contains three trefoil tangles of the same handedness and a \(9_7^3\) link (a type of cyclic [3]catenane topologically constrained to always have at least three twists within the links) is reported. Both compounds contain high degrees of topological writhe (w = 9), a structural feature of supercoiled DNA. The entwined products are generated from the cyclization of a hexameric Fe(ii) circular helicate by ring-closing olefin metathesis, with the mixture of topological isomers formed as a result of different ligand connectivity patterns. The metal-coordinated composite knot was isolated by crystallization, the topology unambiguously proven by tandem mass spectrometry, with X-ray crystallography confirming that the 324-atom loop crosses itself nine times with matching handedness (all Δ or all Λ) at every metal centre within each molecule. Controlling the connectivity of the ligand end groups on circular metal helicate scaffolds provides an effective synthetic strategy for the stereoselective synthesis of composite knots and other complex molecular topologies.

同时合成一个分子九个交叉的复合结，该复合结包含三个相同手性的三叶缠结和一个（9_7 ^ 3 \）链接（一种受拓扑约束的环[3]环烷的类型，在其中始终具有至少三个扭曲）链接）。两种化合物都具有高度的拓扑结构扭曲（w  =  9），这是超螺旋DNA的结构特征。缠绕在一起的产物是由六聚Fe（ii）的环化生成的）通过闭环烯烃复分解反应形成环状螺旋结构，由于不同的配体连接方式，形成了拓扑异构体的混合物。通过结晶分离出金属配位的复合物结，通过串联质谱法明确证实了该拓扑，X射线晶体学证实，每个金属中心的324原子环相交九次都具有相称的手性（全部Δ或全部Λ）每个分子内。控制圆形金属螺旋支架上配体端基的连通性为复合结和其他复杂分子拓扑的立体选择性合成提供了有效的合成策略。