Addition of excess CF3CO2H (HTFA) to [Rh2Pt2(CO)7(PPh3)3], I, under nitrogen results in the formation of a salt (X2+ Y2), which contains only the second example of a di-cationic carbonyl hydride tetra-nuclear cluster, [H2Rh2Pt2(CO)7(PPh3)3]2+, X2+, and a presently partially characterized polymetallic anion Y2. The di-cation X2+ has been characterized by mass spectrometry and a variety of multinuclear NMR methods. Since there is no difference in the electron count for I and X2+, it is probable that both I and X2+ adopt similar butterfly metallic frameworks with a Rh–Rh hinge; in X2+, there are two bridging hydrides to the same wing-tip Pt but the phosphine site occupancies on the Rh2Pt2-framework in I and X2+ are different.
Heaton, B. T., Iggo, J. A., Podkorytov, I. S., Ponomarenko, V. I., Selivanov, S. I., & Tunik, S. P. (2010). A Rare Example of a Di-cationic Hydrido Carbonyl Tetra-nuclear Cluster, [H2Rh2Pt2(CO)7(PPh3)3]2+. Inorganica Chimica Acta, 363(3), 549-554. https://doi.org/10.1016/j.ica.2009.03.045