A tetravalent cerium complex containing a Ce=O bond.

Whereas terminal oxo complexes of transition and actinide elements are well documented, analogous lanthanide complexes have not been reported to date. Herein, we report the synthesis and structure of a cerium(IV) oxo complex, [CeO(LOEt )2 (H2 O)]⋅MeC(O)NH2 (1; LOEt (-) =[Co(η(5) -C5 H5 ){P(O)(OEt)2 }3 ](-) ), featuring a short CeO bond (1.857(3) Å). DFT calculations indicate that the hydrogen bond to cocrystallized acetamide plays a key role in stabilizing the CeO moiety of 1 in the solid state. Complex 1 exhibits oxidizing and nucleophilic reactivity.