Templation and Concentration Drive Conversion Between a Fe II 12 L 12 Pseudoicosahedron, a Fe II 4 L 4 Tetrahedron, and a Fe II 2 L 3 Helicate.

We report the construction of three structurally distinct self-assembled architectures: Fe II 12 L 12 pseudoicosahedron 1 , Fe II 2 L 3 helicate 2 , and Fe II 4 L 4 tetrahedron 3 , formed from a single triazatriangulenium subcomponent A under different reaction conditions. Pseudoicosahedral capsule 1 is the largest formed through subcomponent self-assembly to date, with an outer-sphere diameter of 5.4 nm and a cavity volume of 15 nm 3 . The outcome of self-assembly depended upon concentration, where the formation of pseudoicosahedron 1 was favored at higher concentrations, while helicate 2 exclusively formed at lower concentrations. The conversion of pseudoicosahedron 1 or helicate 2 into tetrahedron 3 occurred following the addition of a CB 11 H 12 - or B 12 F 12 2- template.