Expanding the Nonaqueous Chemistry of Neptunium: Synthesis and Structural Characterization of [Np(NR2)3Cl], [Np(NR2)3Cl]-, and [Np{N(R)(SiMe2CH2)}2(NR2)]- (R = SiMe3)

Reaction of 3 equiv of NaNR2 (R = SiMe3) with NpCl4(DME)(2) in THF afforded the Np(IV) silylamide complex, [Np(NR2)(3)Cl] (1), in good yield. Reaction of 1 with 1.5 equiv of KC8 in THF, in the presence of 1 equiv of dibenzo-18-crown-6, resulted in formation of [{K(DB-18-C-6)(THF)}(3)(mu(3)-Cl)][Np(NR2)(3)Cl](2) (4), also in good yield. Complex 4 represents the first structurally characterized Np(III) amide. Finally, reaction of NpCl4(DME)(2) with 5 equiv of NaNR2 and 1 equiv of dibenzo-18-crown-6 afforded the Np(IV) bis(metallacycle), [{Na(DB-18-C-6)(Et2O)(0.62)(kappa(1)-DME)(0.38)}(2)(mu-DME)][Np{N(R)(SiMe2CH2)}(2)(NR2)](2) (8), in moderate yield. Complex 8 was characterized by H-1 NMR spectroscopy and X-ray crystallography and represents a rare example of a structurally characterized neptunium-hydrocarbyl complex. To support these studies, we also synthesized the uranium analogues of 4 and 8, namely, [K(2,2,2-cryptand)][U(NR2)(3)Cl] (2), [K(DB-18-C-6)(THF)(2)][U(NR2)(3)Cl] (3), [Na(DME)(3)][U{N(R)(SiMe2CH2)}(2)(NR2)] (6), and [{Na(DB-18-C-6)(Et2O)(0.5)(kappa(1)-DME)(0.5)}(2)(mu-DME)][U{N(R)(SiMe2CH2)}(2)(NR2)](2) (7). Complexes 2, 3, 6, and 7 were characterized by a number of techniques, including NMR spectroscopy and X-ray crystallography.

Automated summary

A series of new neptunium and uranium complexes were synthesized and characterized using techniques such as NMR spectroscopy and X-ray crystallography.