Highly Anisotropic Pd 2 L ab 2 L cc 2 and Pd 2 L ab 2 L cd 2 Type Cages by Heteromeric Completive Self-Sorting.

Pd(II)-based low-symmetry coordination cages possessing anisotropic cavities are of great interest. The common strategies employed to achieve such cages utilize either more than one type of symmetrical ligands (e.g., L aa , L bb etc.) or only one type of unsymmetrical ligand (e.g., L ab ). To significantly enhance the anisotropy, we have designed two unsymmetrical bidentate ligands i.e., L ab and L cd , aiming at a low-symmetry Pd 2 L ab 2 L cd 2 -type cage. It was accomplished by high-fidelity integrative self-sorting of two different low-symmetry cages having Pd 2 L ab 4 and Pd 4 L cd 8 -type architectures (homoleptic complexes of the designed ligands). Structural constraints and geometry complementarity in the ligand design drive the non-statistical exclusive self-assembly of the Pd 2 L ab 2 L cd 2 -type cage. By taking advantage of the complemental geometries between ligands, a low-symmetry Pd 2 L ab 2 L cc 2 -type cage was also obtained. Heteromeric completive self-sorting of three homoleptic assemblies (Pd 2 L ab 4 , Pd 4 L cc 8 and Pd 4 L cd 8 -type cages) into an exclusive mixture of Pd 2 L ab 2 L cd 2 and Pd 2 L ab 2 L cc 2 -type mixed ligated assemblies was demonstrated through cage-to-cage transformations.