Synthesis and Reduction of Uranium(V) Imido Complexes with Redox-Active Substituents.

Organic azides that contain naphthyl functional groups were used to prepare uranium(V) imido complexes UV [=NC(2-naph)Ph2 ][N(SiMe3 )2 ]3 (2), UV [=NC(2-naph)3 ][N(SiMe3 )2 ]3 (3), and UV [=N(2-naph)][N(SiMe3 )2 ]3 (4), and their properties were compared with UV [=NCPh3 ][N(SiMe3 )2 ]3 (1). The electronic structures of these compounds were investigated by solution electrochemistry studies, which revealed accessible UV/VI , UIV/V , and naphthalene0 /naphthalene-1 couples. The uranium(V) naphthylimido complexes were reduced by potassium graphite to yield their uranium(IV) congeners K[UIV [=NC(2-naph)Ph2 ][N(SiMe3 )2 ]3 ] (2-K), K[UIV [=NC(2-naph)3 ][N(SiMe3 )2 ]3 ] (3-K), and K[UIV [=N(2-naph)][N(SiMe3 )2 ]3 ] (4-K). The electronic structure of the dianionic compounds were investigated by DFT calculations, and this revealed that the second reduction was ligand-based, which opens the possibility of accomplishing multi-electron redox chemistry by using a tailored multiply-bonded ligand.