Topological prediction of palladium coordination cages.

The preparation of functionalized, heteroleptic Pd L coordination cages is desirable for catalytic and optoelectronic applications. Current rational design of these cages uses the angle between metal-binding (∠) sites of the di(pyridyl)arene linker to predict the topology of homoleptic cages obtained non-covalent chemistry. However, this model neglects the contributions of steric bulk between the pyridyl residues-a prerequisite for endohedrally functionalized cages, and fails to rationalize heteroleptic cages. We describe a classical mechanics (CM) approach to predict the topological outcomes of Pd L coordination cage formation with arbitrary linker combinations, accounting for the electronic effects of coordination and steric effects of linker structure. Initial validation of our CM method with reported homoleptic Pd ( = 2,5-bis(pyridyl)furan) assembly suggested the formation of a minor topology Pd , identified experimentally by mass spectrometry. Application to heteroleptic cage systems employing mixtures of (∠ = 127°) and its thiophene congener (∠ = 149° ∠ = 152.4°) enabled prediction of PdL and PdL coordination cages formation, reliably emulating experimental data. Finally, the topological outcome for exohedrally () and endohedrally () functionalized heteroleptic Pd L coordination cages were predicted to assess the effect of steric bulk on both topological outcomes and coordination cage yields, with comparisons drawn to experimental data.