Abstract
Control over the integrative self-sorting of metallo-supramolecular assemblies opens up possibilities for introducing increased complexity and function into a single self-assembled architecture. Herein, the relationship between the geometry of three ligand components and morphology of three self-sorted heteroleptic [Pd(2) L(2) L'(2) ](4+) cages is examined. Pd-mediated assembly of two bis-monodentate pyridyl ligands with native bite angles of 75° and 120° affords a cis-[Pd(2) L(2) L'(2) ](4+) cage while the same reaction with two ligands with bite angles of 75° and 60° gives an unprecedented, self-penetrating structural motif; a trans-[Pd(2) (anti-L)(2) L'(2) ](4+) heteroleptic cage with a "doubly bridged figure eight" topology. Each heteroleptic assembly can be formed by cage-to-cage conversion of the homoleptic precursors and morphological control of [Pd(2) L(2) L'(2) ] cages is achieved by selective ligand displacement transformations in a system of three ligands and at least six possible cage products.