A Combined Experimental and Theoretical Study of the Versatile Reactivity of an Oxocerium(IV) Complex: Concerted Versus Reductive Addition

A combined experimental and theoretical investigation on the cerium(IV) oxo complex [(L OEt ) 2 Ce(=O)(H 2 O)] ⋅ MeC(O)NH 2 ( 1 ; L OEt − =[Co(η 5 ‐C 5 H 5 ){P(O)(OEt) 2 } 3 ] − ) demonstrates that the intermediate spin‐state nature of the ground state of the cerium complex is responsible for the versatility of its reactivity towards small molecules such as CO, CO 2 , SO 2 , and NO. CASSCF calculations together with magnetic susceptibility measurements indicate that the ground state of the cerium complex is of multiconfigurational character and comprised of 74 % of Ce IV and 26 % of Ce III . The latter is found to be responsible for its reductive addition behavior towards CO, SO 2 , and NO. This is the first report to date on the influence of the multiconfigurational ground state on the reactivity of a metal–oxo complex.