Formation of a Ce(IV) Oxo Complex via Inner Sphere Nitrate Reduction

Reaction of Ce­(NO3)3(THF)4 with Li3(THF)3(NN′3) (NN′3 = N­(CH2CH2NR)3, R = SitBuMe2) in Et2O, in the presence of 12-crown-4, results in the formation of [Li­(12-crown-4)]­[(NN′3)­Ce­(O)] (1) in 36% yield. This transformation proceeds via formation of a Ce­(III) nitrate intermediate, [Li­(12-crown-4)]­[(NN′3)­Ce­(κ2-O2NO)] (2), which undergoes inner sphere nitrate reduction. In addition, reaction of 1 with tBuMe2SiCl results in the formation of (NN′3)­Ce­(OSitBuMe2) (3), confirming the nucleophilic character of its oxo ligand. Natural bond orbital and quantum theory of atoms-in-molecules data reveal the Ce–O interaction in 1 to be significantly covalent, and strikingly similar to analogous U–O bonding.