Isolation of a Tetrameric Cation−Cation Complex of Pentavalent Uranyl

A polymetallic assembly containing mutually coordinated highly reactive UO<sub>2</sub><sup>+</sup> groups was isolated in the presence of dibenzoylmethanate. NMR studies showed unambiguously the presence of the cation−cation complex in pyridine solution while more polar solvents lead to the disruption of the UO<sub>2</sub><sup>+</sup>/UO<sub>2</sub><sup>+</sup> interaction and increased stability.