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, H-1 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.

Automated summary

Two Np(III) halides, NpI3(THF)(4) and NpBr3(THF)(4), have been successfully prepared and characterized by single-crystal X-ray crystallography, H-1 NMR spectroscopy and electronic absorption spectroscopy. A higher yielding synthesis method was used to generate NpI3(THF)(4) and NpBr3(THF)(4) from NpCl4(DME)(2) through reduction and subsequent ligand exchange. These trivalent materials are straightforward to synthesize and can serve as useful starting materials for non-aqueous Np(III) chemistry, eliminating the need for rare and restricted Np metal and elemental halogens.