Presented here are two isostructural uranyl coordination polymers [UO_2(EDO)(H_2O)]?H_2O(1) and [UO_2(BDO)(H_2O)]?2H2_O(2)(EDO^(2-)=ethylene-1,2-dioxamate; BDO^(2-)=butylene-1,2-dioxamate) with identical stepwise zigzag chain structure and distinct interchain hydrogen bonding interaction, prepared from hydrothermal reaction of DEEDO or DEBDO(DEEDO= diethyl ethylene-1,2-dioxamate; DEBDO=diethyl butylene-1,2-dioxamate) with uranyl ions. The monomeric uranyl-based fluorescence emissions of compounds 1 and 2 are red-shifted by about 6 and 5 nm respectively, compared to that of uranyl nitrate hexahydrate. Compound 1 has stronger emission than compound 2, but both their emissions exhibit triple-exponential decay. The photophysics of uranyl oxalate trihydrate was also investigated for comparison. The selective crystallization of compound 1 in alkaline solution was applied to the sequestration of uranyl ions, showing a kinetic preference.
Reported here is a water-soluble ligand, N-(sulfoethyl)-iminodiacetic acid(H3SEIDA), used for the complexation of uranyl ions. A coordination compound composed of uranyl cation and N-(sulfonatoethyl)-ammoniodiacetate(SEADA2?) zwitterion was synthesized from an acidic aqueous solution. This compound features a 2D undulating fes(4.82) coordination layer that is stacked and linked by hydrogen-bonding interaction to form a 3D supramolecular framework with a 1D larger-cycle channel. Thermal analysis demonstrates the relatively weak bonding between uranyl cation and SEADA2? zwitterion. The monomeric uranyl-based fluorescence emission is red-shifted by about 5 nm compared to that of uranyl nitrate hexahydrate. The hydrothermal synthesis of this uranyl compound was successfully applied to the sequestration of uranyl ions.
A series of isomorphic lanthanide coordination polymers [Ln(III)(MBP)_2(NO_3)_2(Br)?2C_3H_6O] [Ln=Eu, Tb, Er, Yb, and Gd; MBP=N,N′-methylene-bis(pyridin-4-one)] featuring polycatenated sql cationic network and incorporated bromide counter ion were prepared. Their visible and near-infrared(NIR) luminescence properties were characterized by steady-state excitation and emission spectra, as well as luminescence lifetimes and quantum yields. The D_(2d) dodecahedron coordination geometry causes visible light excitations and strongly monochromatic emissions. The external heavy-atom environment induces remarkable enhancement on the NIR emissions. The sensitization processes are revealed by analyzing the electronic properties of MBP ligand.
