NMR-Based Structure Determination of an Intertwined Coordination Cage Resembling a Double Trefoil Knot


  • This work was funded by the DFG IRTG 1422. We thank Dr. H. Frauendorf for the HRMS measurements and Prof. Dr. C. Griesinger (MPI Göttingen) for access to his NMR facilities.


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A knot that ties itself! The entanglement of six ligands coordinated to three PdII ions results in the quantitative formation of a walnut-shaped supramolecular cage. Each of the two hemispheres resembles a trefoil knot. The solution-state structure was elucidated using a combination of NMR experiments and calculated model structures. The final structure was selected from several models by topological analyses and encapsulation of chiral camphorsulfonate ions.