Neptunium Alkoxide Chemistry: Expanding Alkoxides to the Transuranium Elements

Two oxo-containing neptunium(IV) tert-butoxides, [Np3O((OBu)-Bu-t)(10)] (1) and [K4Np2O((OBu)-Bu-t)(10)] (2), were synthesized using the ligand substitution between neptunium(IV) silylamides and HOtBu, whereas the salt metathesis between [NpCl4(DME)(2)] (DME = dimethoxyethane) and various amounts of LiOtBu resulted in the formation of oxo-free alkoxides [Np((OBu)-Bu-t)(4)(py)(2)] (3; py = pyridine) and [Li(THF)](2)[Np((OBu)-Bu-t)(6)] (4; THF = tetrahydrofuran). These complexes are the first structurally characterized neptunium(IV) alkoxides using single-crystal X-ray diffraction and solid-state absorption spectroscopy, which provide data for the development of anhydrous metal-organic neptunium chemistry.