Tetravalent Cerium Alkyl and Benzyl Complexes.

High-valent cerium complexes of alkyl and benzyl ligands are unprecedented due to the incompatibility of the typically highly oxidizing Ce 4+ ion and the reducing alkyl or benzyl ligand. Herein we report the synthesis and isolation of the first tetravalent cerium alkyl and benzyl complexes supported by the tri- tert -butyl imidophosphorane ligand, [NP( t Bu) 3 ] 1- . The Ce 4+ monoiodide complex, [Ce 4+ I(NP( tert -butyl) 3 ) 3 ] ( 1-CeI ), serves as a precursor to the alkyl and benzyl complexes, [Ce 4+ (Npt)(NP( tert -butyl) 3 ) 3 ] ( 2-CeNpt ) (Npt = neopentyl, CH 2 C(CH 3 ) 3 ) and [Ce 4+ (Bn)(NP( tert -butyl) 3 ) 3 ] ( 2-CeBn ) (Bn = benzyl, CH 2 Ph). The bonding and structure of these complexes are characterized by single-crystal XRD, NMR and UV-vis-NIR spectroscopy, cyclic voltammetry, and DFT studies.