Synthesis of Non-Aqueous Neptunium(III) Halide Solvates from NpO2.

Two Np(III) halides, NpI3 (THF)4 and NpBr3 (THF)4 , have been prepared and isolated in high yields as described in this work. Starting with neptunia (NpO2 ), NpCl4 (DME)2 was first generated in an updated, higher yielding synthesis than what was previously reported by using HCl/HF. This material was then reduced with KC8 , followed by subsequent ligand exchange, to generate NpBr3 (THF)4 and NpI3 -(THF)4 . Full characterization by single-crystal X-ray crystallography, 1 H NMR spectroscopy and electronic absorption spectroscopy confirmed the molecular formulas and oxidation states. These trivalent materials are straightforward to synthesize and can be used as starting materials for non-aqueous Np(III) chemistry, obviating the need for rare and restricted Np metal and elemental halogens.