In Situ Formation of Unprecedented Neptunium-Oxide Wheel Clusters Stabilized in a Metal–Organic Framework

An isostructural series of Np­(V) MOFs with shp-topology were synthesized and characterized. X-ray diffraction data revealed an unusual wheel-shaped node of 18 neptunyl polyhedra stabilized in the framework. Strong distortion in local coordination of the neptunium atoms is evidenced by Np–Oyl bond lengths that lie outside the typical range for Np­(V). The structure was further interrogated by Raman spectroscopy and density functional theory calculations to assign the vibrational modes.