Synthesis, Spectroscopic Studies and Supramolecular Architecture in a Dinuclear Uranyl Complex, 2-Aminopyridinium [bis(µ2-hydroxo)-tetrakis(nitrato–κ2–O,O′)-tetraoxo-diuranium(VI)] Monohydrate

Abstract

The titled dinuclear uranyl complex, U2O18N4H2·2(C5H7N2) 2(H2O) was crystallised in Monoclinic (C2/c) space group with the cell parameters a = 18.0728(3) b = 10.6896(3) c = 13.9068(3)A, α = γ = 90.00° β = 103.988(2)°. In the structure, the U(VI) atom is eight coordinated with slightly distorted hexagonal bipyramidal geometry around the U(VI) ion. Two oxide ligands in the axial positions and four oxygen atoms from two bidentate nitrate ligands and two oxygen atoms from two hydroxy groups in the equatorial plane form the coordination sphere around the uranium atom. The two hydroxy groups act as bridging ligands between the uranyl ions generating a dinuclear unit having an inversion centre. The coordinated and non coordinated nitrate O atoms, axial uranyl O atoms, bridged hydroxy O atom, the non coordinated 2-aminopyridinium ion and the lattice water molecule play a vital role in assembling the three-dimensional structure via an extensive network of intermolecular O–H···O, N–H···O and C–H···O hydrogen bonds and aromatic π–π stacking interaction. The U(VI) atom is eight coordinated with slightly distorted hexagonal bipyramidal geometry. The three-dimensional structure is built through extensive network of intermolecular O–H···O, N–H···O, C–H···O hydrogen bonds and aromatic π–π stacking interaction.