This metalla-cube is highly cytotoxic, with an IC₅₀ value of 2.1 mM against A2780 cancer cells and 3.8 mM against the cisplatin resistant A2780cisR cells. Its characterization by NMR spectroscopy was challenging: for the benzoquinone moiety, the impossibility to distinguish between closed ¹³C signals in a standard ¹H-¹³C HSQC experiment is readily demonstrated (top), in which only two distinct cross peaks out of the six are identified.
On the other hand, the 10-ppm HSQC experiment increases the resolution in the ¹³C dimension by a factor of about 25, thus enabling to separate all resonances. Indeed, the six independent signals of the three benzoquinone groups are now resolved (bottom), thus confirming the structure of the metalla-cube.

The NMR investigation was carried out by Dr. Julien Furrer.

References:

• N. P. E. Barry, O. Zava, J. Furrer, P. J. Dyson and B. Therrien;
  "Anticancer activity of opened arene ruthenium metalla-assemblies"
  Dalton Trans., 39, 5272-5277, (2010); doi:10.1039/c001521k.