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

[Image: see text] 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.