Steric effects in complexes of diphenyl(2-pyridyl)phosphine oxide with the uranyl ion. Synthetic, structural and theoretical studies

Abstract

Uranyl complexes containing diphenyl(2-pyridyl)phosphine oxide, with the formulae [UO2(NO3)2({C6H5}2POC5H4N)2] (1) and [UO2(DBM)2({C6H5}2POC5H4N)] (2) (where DBM=C6H5COCHCOC6H5), were prepared and characterized by IR, NMR spectroscopic and elemental analysis methods. The structures of the compounds were determined by X-ray diffraction methods and revealed a monodentate mode of bonding for the ligand through the phosphine oxide oxygen atom to the uranyl group. The pyridyl nitrogen atom of the ligand is uncoordinated. The uranyl group is surrounded by eight oxygen atoms in a hexagonal bi-pyramidal geometry in 1 and seven oxygen atoms in a pentagonal bi-pyramidal geometry in 2.