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.

具有Cs对称（Cs-symmetric）的四吡啶基钴金属配体2，与三个半三明治型二钌受体3~5进行自组装，成功得到了A4D2型（A代表受体，D代表给体）金属笼6~8，该结果通过电喷雾电离质谱（ESI）、核磁共振波谱（NMR）以及X射线晶体学得以证实。6~8的固态结构解析结果显示，受体单元的长度对这类金属笼的分子堆积具有显著影响。因此在固态条件下，6~8分别呈现出水车状、镊子状及类蝴蝶状的分子构型。