Actinide structural studies. Part 6. A confirmed non-linear uranyl group in dioxobis(pentane-2,4-dionato)pyridineuranium(VI)

Abstract

The crystal structure of the title compound has been determined using X-ray diffraction methods. The complex exhibits pentagonal-bipyramidal co-ordination involving two bidentate pentane-2,4-dionate ions and a pyridine molecule about the uranyl(VI) ion. The metal–ligand oxygen distances are 2.34(1) and 2.44(1)Å, the metal–ligand nitrogen distance is 2.47(1)Å, and the U–O (UO₂²⁺) distances are 1.83(1)Å. The bond angle O–U–O (UO₂²⁺) is 173.5(8)°, confirming the non-linearity previously suggested from spectroscopic evidence. The crystals are orthorhombic, space group Fdd2, with a= 29.702(4), b= 11.433(2), c= 10.593(2)Å, and Z= 8. The structure has been refined to an R value of 0.032 using 832 observed, diffractometer-measured intensities.