Introducing Chlorido Cerium Complexes with the Methoxy Kläui Ligand [Co(η5-C5H5){P(O)(OMe)2}3]−

The treatment of Ce(OH)4 in thionyl chloride and dimethoxyethane (DME) resulted in the formation of a highly unstable red Ce(IV) complex with the composition [CeCl4(DME)2] (1). From the reaction of 1 with the Na[Co(η5-C5H5){P(O)(OMe)2}3] (NaLOMe) salt containing the anionic tripodal Kläui ligand η5-cyclopentadienyltris(dimethylphosphonato)cobaltate(III), the two new cerium(III) complexes [Ce(LOMe)2(H2O)2]Cl·2.5H2O (2), 1D-[Ce(μ-Cl)(LOMe)(H2O)3]Cl (3) and the cerium(IV) complex [CeCl2(LOMe)2]·acetone (4) were obtained and structurally characterized. The complexes 3 and 4 are the first cerium complexes featuring the LOMe ligand together with chlorido ligands. Due to the potential exchange of the chloride counterions with other ligands in 2−4, these complexes could serve as precursors in molecular cerium coordination chemistry. The assigned cerium oxidation states are supported by the bond valence sum (BVS) method. The 31P-NMR spectra with δ(31P) = 160.20 ppm (2) and 159.43 ppm (3) are diagnostic of cerium(III).