Backbone‐Bridging Promotes Diversity in Heteroleptic Cages
Kai Wu, Bo Zhang, Christoph Drechsler, Julian J. Holstein, Guido H. Clever
Abstract
Abstract The combination of shape‐complementary bis‐monodentate ligands L A and L B with Pd II cations yields heteroleptic cages cis‐[Pd 2 L A 2 L B 2 ] by self‐sorting. Herein, we report how such assemblies can be diversified by introduction of covalent backbone bridges between two L A units. Together with solvent and guest effects, the flexibility of these linkers can modulate nuclearity, topology, and number of cavities in a family of four structurally diverse assemblies. Ligand L A1 , with flexible linker, reacts in CH 3 CN with its L B counterpart to a tetranuclear dimer D1 . In DMSO, however, a trinuclear pseudo‐tetrahedron T1 is formed. The product of L A2 , with rigid linker, looks similar to D1 , but with a rotated ligand arrangement. In presence of an anionic guest, this dimer D2 transforms and a hexanuclear prismatic barrel P2 crystallizes. We demonstrate how controlling a ligand's coordination mode can trigger structural differentiation and increase complexity in metallo‐supramolecular assembly.