Structure of the {U} polyoxo cluster UOCl(MeO) (x = 2.3, MeO = methoxide)

Fichter, S.*; Radoske, T.*; Ikeda, Atsushi  

A new type of polyoxo cluster complex that contains thirteen uranium atoms, {U}, was synthesised and characterised as [U(-O)(-O)(-O)Cl(O)] (x = 2.3, MeO = methoxide) (I). The complex crystallises from methanol containing tetravalent uranium (U) with a basic organic ligand. The characterised {U} polyoxo cluster complex possesses a single cubic uranium polyhedron at the centre of the cluster core. The observed shortening of U-O bonds, together with BVS calculations and the overall negative charge (2-) of (I), suggests that the central uranium atom in (I), that forms the single cubic polyhedron, is presumably oxidised to the pentavalent state (U) from the original tetravalent state (U). Complex I is, hence, the first example of a polyoxo cluster possessing a single cubic coordination polyhedron of U.