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

• Published in: Chemistry : a European journal 2017-04, Vol.23 (24), p.5748-5757
• Main Authors: Mullane, Kimberly C., Carroll, Patrick J., Schelter, Eric J.
• Format: Article
• Language: English
• Subjects: Accessibility; Chemistry; Congeners; electrochemistry; Electronic structure; Graphite; imido; Ligands; Mathematical analysis; redox chemistry; Reduction; Uranium
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201605758

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. Redox activity of uranium imido complexes: Tailored, redox‐active multiply bonded ligands that bear naphthalene moieties are developed in the coordination chemistry of uranium.