Guest Segregation in Heteromeric Multicage Systems

Dynamically interconvertible metallo-supramolecular multicomponent assemblies, coexisting orthogonally in solution, serve as simplified mimics for complex networks found in biological systems. Building on recent advances in controlling the nonstatistical self-assembly of heteroleptic coordination cages and heteromeric completive self-sorting, i.e., the coformation of multiple low-symmetry assemblies, we herein describe the first instance of emerging functionality from a heteromeric multicage system. In particular, one heteroleptic cage coexists in equilibrium with one or two different homoleptic cages, each capable of preferentially encapsulating one out of three guests within their cavities. Guest segregation occurs under thermodynamic control and can be reached following several distinct paths. Each pathway involves different sequential transformations, eventually leading to the same outcome. We found that the most complex mixture of components (three ligands, three guests, plus palladium cations) always yields an ordered, pathway-independent final state of three coexisting host-guest species, thus representing a case of simplexity in self-sorted systems. This study forms a basis for expanding the scope of dynamic transformation processes implemented in multicage host-guest systems. Together with the incorporation of stimuli-responsive elements and other functionality, complex cage populations with bioinspired applications in controllable compound separation schemes, compartmentalized cascade reactions, and multistep (even bifurcated) molecular information processing will become accessible.