Crystal and molecular structure of bis(3-chloropentane-2,4-dionato)-dioxo(triphenylphosphine oxide)uranium(VI) and dioxobis(pentane-2,4-dionato)(triphenylphosphine oxide)uranium(VI)–benzene (1/1)

Abstract

The crystal structures of the title complexes have been determined by single-crystal X-ray diffraction. The first, [UO₂(3Cl-pd)₂(PPh₃O)], is monoclinic and the second, [UO₂(pd)₂(PPh₃O)]·C₆H₆, belongs to the triclinic system. Both structures are molecular, with no strong association between molecules except for van der Waals forces and possible weak hydrogen-bond attractions. In each crystal the uranium co-ordination polyhedron is a pentagonal bipyramid. The packing of the complex molecules in the two structures is quite different, owing to the presence of the large chlorine atom in the first crystal and the solvent molecule in the second. In the chlorodiketonate the molecular planes are both mutually perpendicular and parallel, but in the unsubstituted diketonate are parallel only. The pentane-2,4-dionate molecules and the pentagonal ring have an L-shaped system in the chloro-derivative and a chair shape in the unsubstituted derivative.