Investigation of Uranium Tris(imido) Complexes: Synthesis, Characterization, and Reduction Chemistry of [U(NDIPP)3(thf)3]

Addition of KC8 to trivalent [UI3(thf)(4)] in the presence of three equivalents of 2,6-diisopropylphenylazide (N3DIPP) results in the formation of the hexavalent uranium tris(imido) complex [U(NDIPP)(3)(thf)(3)] (1) through a facile, single-step synthesis. The X-ray crystal structure shows an octahedral complex that adopts a facial orientation of the imido substituents. This structural trend is maintained during the single-electron reduction of 1 to form dimeric [U(NDIPP)(3){K(Et2O)}](2) (2). Variable-temperature/field magnetization studies of 2 show two independent U-V 5f(1) centers, with no antiferromagnetic coupling present. Characterization of these complexes was accomplished using single-crystal X-ray diffraction, variable-temperature (HNMR)-H-1 spectroscopy, as well as IR and UV/Vis absorption spectroscopic studies.