NN-dimethyl- and NN-diethyl-propionamide complexes of uranium tetrachloride; crystal structure of trichlorotetrakis(NN-diethylpropion- amide)uranium(IV) pentachloro(NN-diethylpropionamide)uranate(IV), [UCl3(EtCONEt2)4]+[UCl5(EtCONEt2)]–

Abstract

The complexes UCl₄·xL [x= 2 or 2.5, L = EtCONMe₂(dmpa) and EtCONEt₂(depa)] have been prepared and their u.v.–visible and i.r. spectra are reported. The crystal and molecular structure of UCl₄·2.5depa has been determined from single-crystal, X-ray diffractometer data and refined by least squares to R 0.0478 for 3 386 independent reflections. Crystals of U₂Cl₈·5depe are monoclinic, space group P2₁(no. 4), with Z = 2, a= 16.817(2), b= 10.339(1), c= 16.400(2)Å, and β= 104.99(1)°. The compound is ionic, [UCl₃(depa)₄]⁺[UCl₅(depa)]^–, and the co-ordination geometry about the seven-co-ordinate uranium atom in the cation is pentagonal bipyramidal, while that about the six-co-ordinate uranium atom in the anion is octahedral.