Orientational self-sorting in cuboctahedral Pd cages.

Cuboctahedral coordination cages of the general formula [PdL] (L = low-symmetry ligand) were analyzed theoretically and experimentally. With 350 696 potential isomers, the structural space of these assemblies is vast. Orientational self-sorting refers to the preferential formation of particular isomers within the pool of potential structures. Geometric and computational analyses predict the preferred formation of cages with a arrangement at the metal centers. This prediction was corroborated experimentally by synthesizing a [PdL] cage with a bridging 3-(4-(pyridin-4-yl)phenyl)pyridine ligand. A crystallographic analysis of this assembly showed exclusive coordination of the 3- and the 4-pyridyl donor groups at the Pd ions.