Chemistry of the uranyl group. Part IV. Preparation and properties of triphenyl-phosphine and -arsine oxide complexes of uranyl dithioacetate and dithiobenzoate, and the structure of bis(dithioacetato)dioxo-(triphenylphosphine oxide)uranium(VI)

Abstract

Monomeric complexes of formula UO₂(MeCS₂)₂L and UO₂(PhCS₂)₂L (L = Ph₃PO and Ph₃AsO) have been synthesized and characterized. The crystal structure of UO₂(MeCS₂)₂(Ph₃PO) has been determined from three-dimensional counter data by Patterson and electron-density syntheses and refined by least-squares to R 0·077 for 3924 reflections. The crystals are monoclinic, space-group P2₁/c, with a= 16·728 Å, b= 11·001 Å, c= 15·678 Å, β= 113° 29′, Z= 4. The uranium(VI) atom is in a seven-co-ordinate, pentagonal-bipyramidal environment. The linear uranyl group is perpendicular to the equatorial plane in which four sulphur atoms of two dithioacetate groups and the oxygen atom of the ligand occupy the corners of an irregular pentagon.