[{[(η7-C2B10H12)(η6-C2B10H12)U][K2(thf)5]}2]: A Metallacarborane Containing the Novel η7-C2B10H124− Ligand

The tetranion ligand η⁷-C₂B₁₀H₁₂⁴⁻ has been observed for the first time in 1 , which was obtained from the reaction of o-C₂B₁₀H₁₂ with excess K metal followed by treatment with UCl₄. As shown in the picture (without K cations and coordinated THF molecules), 1 is a centrosymmetric dimer with a bent sandwich structure.