Morphological Control of Heteroleptic cis‐ and trans‐Pd2L2L′2 Cages

摘要

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 [Pd2 >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‐[Pd2 >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‐[Pd2(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 [Pd2 >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.