A Metallosupramolecular Capsule with the Topology of the Tetrahedron, 3(3), Assembled from Four Guanidine-Based Ligands and Twelve Cadmium Centers This work was supported by the "Deutsche Forschungsgemeinschaft" DFG and the Australian Research Council. The authors thank Dr. B. F. Abrahams for help with the X-ray crystallography.