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.