Design Rules for Controlling Connectivity, Topology, and Sorting Using Hydrogen-Bonded Pairs and Aromatic Components in Palladium(II)-Based Interlocked and Foldameric Systems.

Nature's exquisite control over structure arises from its use of complex arrays of topologically complicated species capable of forming and functioning orthogonally. Chemists seek the same level of control in synthetic systems, and here we report the design rules for self-assembly of systems integrating metal-coordination to Pd(II), complementary geometries, interligand hydrogen bonding, and π─π interactions. This has been achieved by integrating hydrogen-bonded complementary pairs, AA:DD and DA:AD (A = acceptor, D = donor), and complementary aromatic regions of high and low electron density into a series of ligands which controllably self-assemble into defined three-dimensional structures with Pd(II). These rules have allowed us to elucidate pathways to multiple molecular types with defined connectivity and topology, including metallo-foldamers, cyclic species, and an interlocked clippane formed under thermodynamic control. We have also established that, despite similarities between their respective components, these diverse structures persist in a combinatorial mixture.