Synthesis and structure of [CeF4(Me2SO)2]—A rare neutral ligand complex of a lanthanide tetrafluoride

Hydrated cerium(IV) fluoride dissolves in hot dimethylsulfoxide to form yellow [CeF4(Me2SO)2], the X-ray structure of which reveals a chain polymer with eight-coordinate cerium bound to two terminal and four bridging fluorines and two O-bonded Me2SO molecules. The complex was also characterised by IR, 1H and 19F{1H} NMR and UV/visible spectroscopies. Attempts to use [CeF4(Me2SO)2] as a synthon to prepare other complexes with phosphine oxides or 2,2′-bipyridyl were unsuccessful. Thorium(IV) fluoride hydrate does not react with boiling dmso.