Templation and Concentration Drive Conversion Between a (Fe12L12)-L-II Pseudoicosahedron, a (Fe4L4)-L-II Tetrahedron, and a (Fe2L3)-L-II Helicate

We report the construction of three structurally distinct self-assembled architectures: (Fe12L12)-L-II pseudoicosahedron 1, (Fe2L3)-L-II helicate 2, and (Fe4L4)-L-II 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 CB11H12- or B12F122- template.