Assembly of a Truncated-Tetrahedral Chiral [M12(μ-L)18]24+ Cage

Instead of the expected tetrahedral M4L6 cage, a far more complicated M12L18 cage forms when the bridging ligand shown reacts with CoII ions. The dodecanuclear cage has the topology of a tetrahedron in which all four vertices are truncated to reveal triangular faces. A bridging ligand spans each of the 18 edges of the metal cage, and all 12 metal–tris(chelate) centers are homochiral. [BF4]− ions are located in the large central cavity and in the two-dimensional cavities at the center of each face.