Equatorial penta coordination in uranyl complexes with N-ethylenedimethylaminesalicylaldimine

The crystal and molecular structure of bis(N-ethylenedimethylaminesalicylaldiminato) dioxouranium(VI), C22H30N4O4U, has been determined by three-dimensional X-ray methods. The crystals are triclinic, space group P1 with cell dimensions a = 10·501[8], b = 11·250[8], c = 10·729[11] Å, α = 103·97[9], β = 99·17[16], γ = 99·70[8]°; Dm = 1·82, Z = 2, Dc = 1·83 g cm−3. The structure was solved by the conventional heavy-atom method from 2973 reflections collected by counter, and refined by least-squares method to a conventional R factor of 0·034.Each uranium atom is in a pentagonal-bipyramidal environment; the coordination plane is comprised of the two oxygen and three nitrogen atoms of two potentially tridentate Schiff bases with the uranyl group perpendicular to this plane. The UO apical distances are both 1·78[1] Å and the equatorial 2·24[1] Å; the UN distances are 2·57[1], 2·59[1] and 2·69[1] Å, in accordance with the two different electronic situations at the nitrogen atoms. The complex exhibits an overall “stepped” geometry with the -CH2CH2- carbon atoms out from the equatorial plane by 0·27 and −0·54 Å.