Structure and small molecule activation reactivity of a metallasilsesquioxane of divalent ytterbium.

The first metallasilsesquioxane of a divalent lanthanide, [Yb{Cy7Si7O11(OSiMe3)}(THF)]2, 1, was synthesized and structurally characterized. The Cy7Si7O11(OSiMe3)2- ligands in 1 bind two Yb(ii) ions in a bridging mode. The dinuclear complex effects the two-electron reduction of azobenzene yielding the Yb(iii) complex [{Yb(Cy7Si7O11(OSiMe3))(THF)2}2(PhNNPh)], 2, and the CO2 reduction to CO and carbonate.