A homoleptic η² hydroxylaminato Ce(IV) complex with S₄ symmetry.

An electron rich, air-stable hydroxylamine ligand and a strongly stabilized cerium(IV) hydroxylaminato complex are described. The synthesis of Ce[η(2)-ON((t)Bu)(2-OMe-5-(t)Bu-C6H3)]4 (1) proceeded through a one pot protonolysis and oxidation procedure. Complex 1 crystallized with the molecule in exact S4 symmetry. The hydroxylaminato ligands were bound in an η(2) mode that is of interest for potential application in the separations chemistry of rare earth metals.