Iodine networks in polyiodides of M(III) urea complexes: Crystal structures of [V(Ur)6][I3]3 and [Dy(Ur)8][I5][I3]2[I2]

Unique [V(Ur)6][I3]3 and [Ln(Ur)8][I5][I3]2[I2] (Ln = Dy, La) were prepared by reactions of hexaureavanadium(III) and tetraaquatetraurealanthanide(III) iodides with iodine and the crystal structures of the vanadium and dysprosium compounds are reported. Metal ions are located at the centres of distorted octahedral and square-antiprismatic arrangements, respectively, of oxygen atoms of covalent-coordinated urea. The triiodide anions in the vanadium polyiodide are united in infinite helical chains fitting between the columns of complex cations and binding them together by hydrogen bonding. In the dysprosium polyiodide, the V-shaped I5− ions are united in infinite planar twisting chains. The chains are connected by short contacts through bridging V-shaped I5− ions (combined of I2 molecule and I3− ion) and symmetric I3− ions. Another I3− ion is isolated. The bonded iodine atoms form hexahedral channels, and the columns of the complex cations are localized in these channels and stabilized by hydrogen bonding.

Graphical abstractUnique [V(Ur)6][I3]3 and [Ln(Ur)8][I5][I3]2[I2] (Ln = Dy, La) were prepared by reactions of hexaureavanadium(III) and tetraaquatetraurealanthanide(III) iodides with iodine and the crystal structures of the vanadium and dysprosium compounds are reported.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Polyiodides [V(Ur)6][I3]3 and [Ln(Ur)8][I5][I3]2[I2] (Ln = Dy, La) were prepared. ► Crystal structures of vanadium(III) and dysprosium(III) polyiodides were studied. ► Structures of polyiodides in the V-Cr-Fe and La-Dy-Tm-Yb-Lu rows are discussed.