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.