Ruthenium–Cobalt Bimetallic Supramolecular Cages via a Less Symmetric Tetrapyridyl Metalloligand and the Effect of Spacer Units

The self-assembly of Cs-symmetric tetra­pyridyl cobalt–​metallo­ligand 2 with three half-sandwich diruthenium acceptors, 3–5, led to the formation of A4D2 (A = acceptor, D = donor) metalla­cages 6–8, as shown by ESI mass spectrometry, NMR spectroscopy, and X-ray crystallography. The solid-state structures of 6–8 revealed that the length of the acceptor unit greatly influences the molecular packing of these metalla­cages. Hence, in the solid state, 6–8 can be considered to have water­wheel-shaped, tweezer-shaped, and butterfly-like architectures, respectively.