Imidazolin‐2‐iminato Cerium(IV) Chlorides: Synthesis, Structure and Electrochemical Properties.

The ligand field greatly affects the redox properties of cerium. Herein, cerium(III) and cerium(IV) complexes supported by imidazolin‐2‐iminato ligands were synthesized and structurally characterized, and their electrochemical properties were investigated. Silylamine elimination of cerium(III) amide Ce{N(SiMe3)2}3 with imidazolin‐2‐imine ImRNH (R=Mes, tBu, iPr) provided imidazolin‐2‐iminato cerium(III) complexes, [(ImMesN)(ImMesNH)Ce{N(SiMe3)2}2] (1), [(ImtBuN)2(ImtBuNH)Ce{N(SiMe3)2}] (2) and [(ImiPrN)2(ImiPrNH)Ce(μ‐ImiPrN)]2 (4) in 71–85% yields. These cerium(III) complexes were successfully oxidized by Ph3CCl or C2Cl6 to afford imidazolin‐2‐iminato cerium(IV) chlorides, [(ImMesN)2Ce{N(SiMe3)2}Cl] (5), [(ImtBuN)3CeCl] (6) and [(ImiPrN)2Ce(μ‐ImiPrN)Cl]2 (7) in 70%–76% yields. All complexes were characterized by the single‐crystal X‐ray diffraction, which showed that 1, 2, 5 and 6 are monomers while 4 and 7 are dimers. The electrochemical studies indicated that the Ce(III/IV) couples for 5 and 6 are more negative than those of silylamido cerium(IV) complexes, and the Ce(III/IV) couples for 1 and 2 have a similar trend. [ABSTRACT FROM AUTHOR]