Supramolecular architectures of two novel organic-inorganic hybrid materials containing identical monomeric uranyl units.

Two isostructural uranyl complexes have been crystallized with different bipyridyl cations to yield the compounds hemi(4,4'-bipyridinium) tris(5-chlorothiophene-2-carboxylato)dioxidouranate(VI) monohydrate, (C(10)H(10)N(2))(0.5)[U(C(5)H(2)ClO(2)S)(3)O(2)]·H(2)O, (I), and hemi[4,4'-(ethane-1,2-diyl)dipyridinium] tris(5-chlorothiophene-2-carboxylato)dioxidouranate(VI) monohydrate, (C(12)H(14)N(2))(0.5)[U(C(5)H(2)ClO(2)S)(3)O(2)]·H(2)O, (II). In the [UO(2)X(3)](-) complexes (X is 5-chlorothiophene-2-carboxylate), the uranyl O atoms occupy the two axial positions and the equatorial positions are occupied by six O atoms of the three X ions so that each U atom is eight coordinated in a puckered hexagonal-bipyramidal structure. In both compounds, the metal centres are linked by classical O-H...O and N-H...O hydrogen bonds involving the coordinated ligands, the diprotonated organic linker cation (which rests on a centre of inversion at the mid-point of the central C-C bond) and water molecules. The crystal structures are further stabilized by weak C-H...O and π-π stacking interactions, forming similar three-dimensional supramolecular architectures, forming a two-dimensional network parallel to the (100) plane in (I) and a three-dimensional network in (II).