In situ deca-rbonylation of N,N-di-methyl-formamide to form di-methyl-ammonium cations in the hybrid framework compound {[(CH3)2NH2]2[Zn{O3PC6H2(OH)2PO3}]} n.

The title phospho-nate-based organic-inorganic hybrid framework, poly[bis(dimethylammonium) [(µ4-2,5-dihydroxybenzene-1,4-diphosphonato)zinc(II)]], {(C2H8N)2[Zn(C6H4O8P2)]} n , was formed unexpectedly when di-methyl-ammonium cations were formed from the in situ deca-rbonylation of the N,N-di-methyl-formamide solvent. The framework is built up from ZnO4 tetra-hedra and bridging di-phospho-nate tetra-anions to generate a three-dimensional network comprising [100] channels occupied by the (CH3)2NH2 + cations. Within the channels, an array of N-H⋯O hydrogen bonds help to establish the structure. In addition, intra-molecular O-H⋯O hydrogen bonds between the appended -OH groups of the phenyl ring and adjacent PO3 2- groups are observed.

Hybrid Uranyl-Phosphonate Coordination Nanocage.

We report herein a general synthetic approach for designing uranyl coordination cages. Compounds 1 and 2 are constructed through a temperature-dependent and solvent-driven self-assembly. In both cases, the synthetic strategy involves in situ phosphonate ligand condensation into a flexible pyrophosphonate ligand. This pyrophosphonate ligand formation is essential for the introduction of curvature into these compounds. In the presence of PF6- ions that are derived from hydrofluoric acid, a macrocyclic uranyl-phosphonate discrete compound, 1, whose cavity contains PF6- ions, hydronium ions, and water molecules, is obtained. When Cs+ cations are used in the synthesis, a remarkable uranyl coordination nanocage, 2, resulted. The macrocycle (1) is approximately 10.9 × 10.9 Å2 in diameter while the nanocage (2) is approximately 15.0 × 11.3 Å2 in diameter, as measured from the outer oxygen atoms of the uranyl centers. Both compounds are constructed from a UO22+ moiety, coordinated by an additional four oxygen atoms from the phosphonate group to form pentagonal bipyramidal geometry. All the compounds fluoresce at room temperature, showing characteristic vibronically coupled charge-transfer based emission.

Hybrid uranium-transition-metal oxide cage clusters.

Transition-metal based polyoxometalate clusters have been known for decades, whereas those built from uranyl peroxide polyhedra have more recently emerged as a family of complex clusters. Here we report the synthesis and structures of six nanoscale uranyl peroxide cage clusters that contain either tungstate or molybdate polyhedra as part of the cage, as well as phosphate tetrahedra. These transition-metal-uranium hybrid clusters exhibit unique polyhedral connectivities and topologies that include 6-, 7-, 8-, 10-, and 12-membered rings of uranyl polyhedra and uranyl ions coordinated by bidentate peroxide in both trans and cis configurations. The transition-metal polyhedra appear to stabilize unusual units built of uranyl polyhedra, rather than templating their formation.

Incorporation of Cu(2+) ions into nanotubular uranyl diphosphonates.

Three new multidimensional polymetallic uranyl diphosphonates were crystallized under mild hydrothermal conditions: [Cu(H2O)]2{(UO2)4F2[(PO3C6H4)(C6H4PO3H)3]2(bipym)}·6H2O (1), [Cu(H2O)]2{(UO2)4[(C6H4PO3)(C6H4PO3H)]4(bipym)} (2), and Cu{(UO2)(C6H4PO3)2(bipym)}·H2O (3). Compound 1 consists of UO6F pentagonal bipyramids connected by diphosphonate moieties into a tubular channel. The Cu(2+) cations are stabilized between the nanotubular subunits by 2,2'-bipyrimidine (bipym). The structure of 2 is similar to 1, except that it consists of relatively rare UO6 tetragonal bipyramids bridged by diphosphonate groups. Compound 3 also contains UO6 tetragonal bipyramids. Unlike compounds 1 and 2, only two of the tetradentate N atoms of the binucleating bipym group are coordinated. All three compounds show luminescent properties under ambient conditions, with evidence of the characteristic vibronically coupled charge-transfer based uranyl cation emissions.

Hybrid uranyl-carboxyphosphonate cage clusters.

Two new hybrid uranyl-carboxyphosphonate cage clusters built from uranyl peroxide units were crystallized from aqueous solution under ambient conditions in approximately two months. The clusters are built from uranyl hexagonal bipyramids and are connected by employing a secondary metal linker, the 2-carboxyphenylphosphonate ligand. The structure of cluster A is composed of a ten-membered uranyl polyhedral belt that is capped on either end of an elongated cage by five-membered rings of uranyl polyhedra. The structure of cluster B consists of 24 uranyl cations that are arranged into 6 four-membered rings of uranyl polyhedra. Four of the corresponding topological squares are fused together to form a sixteen-membered double uranyl pseudobelt that is capped on either end by 2 topological squares. Cluster A crystallizes over a wide pH range of 4.6-6.8, while cluster B was isolated under narrower pH range of 6.9-7.8. Studies of their fate in aqueous solution upon dissolution of crystals by electrospray ionization mass spectrometry (ESI-MS) and small-angle X-ray scattering (SAXS) provide evidence for their persistence in solution. The well-established characteristic fingerprint from the absorption spectra of the uranium(VI) cations disappears and becomes a nearly featureless peak; nonetheless, the two compounds fluoresce at room temperature.

Hybrid uranyl arsonate coordination nanocages.

Nanoscopic uranyl coordination cages have been prepared by a facile route involving self-assembly via temperature and solvent-driven, in situ ligand synthesis. The synthesis of hydrogen arsenate and pyroarsonate ligands in situ enhances flexibility, which is an important factor in producing these compounds.

Correlations and differences between uranium(VI) arsonates and phosphonates.

Three new uranium arsonate compounds, UO(2)(C(6)H(5))(2)As(2)O(5)(H(2)O) (UPhAs-1), UO(2)(HO(3)AsC(6)H(4)AsO(3)H)(H(2)O)·H(2)O (UPhAs-2), and UO(2)(HO(3)AsC(6)H(4)NH(2))(2)·H(2)O (UPhAs-3) have been synthesized under mild hydrothermal conditions. UPhAs-1 is constructed from UO(7) pentagonal bipyramids that are chelated by the pyroarsonate moiety, [PhAs(O(2))OAs(O(2))Ph](2-), forming chains of layered uranyl polyhedra. Two of the phenylarsonic acids are condensed in situ to form the fused tetrahedra of the pyroarsonate moiety through a metal-mediated, thermally induced condensation process. The structure of UPhAs-2 consists of UO(7) pentagonal bipyramids that are chelated by phenylenediarsonate ligands, forming one-dimensional chains of uranyl polyhedra. UPhAs-3 consists of a rare UO(6) tetragonally distorted octahedron (D(4h)) that is on a center of symmetry and linked to two pairs of adjacent 4-aminophenylarsonate ligands. This linear chain structure is networked through hydrogen bonds between the lattice water molecules and the -NH(2) moiety. All three of these compounds fluoresce at room temperature, showing characteristic vibronically coupled charge-transfer based emission.

One-dimensional uranyl-2,2'-bipyridine coordination polymer with cation-cation interactions: (UO2)2(2,2'-bpy)(CH3CO2)(O)(OH).

A uranyl-2,2'-bipyridine coordination polymer, (UO(2))(2)(2,2'-bpy)(CH(3)CO(2))(O)(OH) (1; 2,2'-bpy = 2,2'-bipyridine) has been synthesized hydrothermally at 165 °C and characterized via single-crystal X-ray diffraction and UV-vis-near-IR, fluorescence, and IR spectroscopies. The structure consists of two uranyl pentagonal bipyramids that are linked through cation-cation interactions (CCIs) to form chains that are truncated in the second and third dimensions by 2,2'-bpy. These chains of uranyl polyhedra consist of a rare case of CCIs through the edge-sharing polyhedral connection mode instead of the more common corner-sharing connection mode. 1 is the first uranium(VI) compound reported that contains CCIs in which the structural unit is one-dimensional, although lower-dimensional structural units with CCIs are known for pentavalent actinides.

1-Benzyl-3-[(4-methyl-phen-yl)imino]-indolin-2-one.

In the title compound, C(22)H(18)N(2)O, the phenyl and tolyl rings make dihedral angles of 84.71 (7) and 65.11 (6)°, respectively, with the isatin group. The aromatic rings make a dihedral angle of 60.90 (8)°. The imino C=N double bond, exists in an E conformation. In the crystal, mol-ecules are linked by weak π-π stacking inter-actions [centroid-centroid distance = 3.6598 (13) Å].

11-(4-Meth-oxy-phen-yl)-3,3-dimethyl-2,3,4,5,10,11-hexa-hydro-1H-dibenzo[b,e][1,4]diazepin-1-one monohydrate.

In the title compound, C(22)H(24)N(2)O(2)·H(2)O, the co-crystallized water mol-ecule inter-acts with the N and O atoms of the mol-ecule through O(w)-H⋯N, O(w)-H⋯O(meth-yl) and N-H⋯O(w) hydrogen-bonding inter-actions. These hydrogen bonds, along with the inter-molecular N-H⋯O=C hydrogen-bonding inter-actions, connect the mol-ecules into a three-dimensional network. The dihedral angle between the two aromatic rings is 65.46 (10)°.

Uranyl heteropolyoxometalate: synthesis, structure, and spectroscopic properties.

A novel uranium heteropolyoxometalate, [H(3)O](4)[Ni(H(2)O)(3)](4){Ni[(UO(2))(PO(3)C(6)H(4)CO(2))](3)(PO(4)H)}(4)·2.72H(2)O, has been prepared under mild hydrothermal conditions using the diethyl(2-ethoxycarbonylphenyl)phosphonate ligand and in situ ligand synthesis of the HPO(4)(2-) anion. The cluster is derived from a common UO(7), pentagonal bipyramid and is constructed by employing nickel(II) metal ions as linkers. The 3d-5f heteropolyoxometalate core incorporates 12 classical pentagonal uranyl groups and four Ni(2+) octahedral units.

Metal-controlled assembly of uranyl diphosphonates toward the design of functional uranyl nanotubules.

Two uranyl nanotubules with elliptical cross sections were synthesized in high yield from complex and large oxoanions using hydrothermal reactions of uranyl salts with 1,4-benzenebisphosphonic acid or 4,4'-biphenylenbisphosphonic acid and Cs(+) or Rb(+) cations in the presence of hydrofluoric acid. Disordered Cs(+)/Rb(+) cations and solvent molecules are present within and/or between the nanotubules. Ion-exchange experiments with A(2){(UO(2))(2)F(PO(3)HC(6)H(4)C(6)H(4)PO(3)H)(PO(3)HC(6)H(4)C(6)H(4)PO(3))}·2H(2)O (A = Cs(+), Rb(+)), revealed that A(+) cations can be exchanged for Ag(+) ions. The uranyl phenyldiphosphonate nanotubules, Cs(3.62)H(0.38)[(UO(2))(4){C(6)H(4)(PO(2)OH)(2)}(3){C(6)H(4)(PO(3))(2)}F(2)]·nH(2)O, show high stability and exceptional ion-exchange properties toward monovalent cations, as demonstrated by ion-exchange studies with selected cations, Na(+), K(+), Tl(+), and Ag(+). Studies on ion-exchanged single crystal using scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM/EDS) provide evidence for chemical zonation in Cs(3.62)H(0.38)[(UO(2))(4){C(6)H(4)(PO(2)OH)(2)}(3){C(6)H(4)(PO(3))(2)}F(2)]·nH(2)O, as might be expected for exchange through a diffusion mechanism.

Comparison of thorium(IV) and uranium(VI) carboxyphosphonates.

The hydrothermal reactions of thorium nitrate and uranyl acetate with carboxyphenylphosphonic acid and HF result in the formation of ThF(2)(PO(3)C(6)H(4)CO(2)H) and UO(2)(PO(3)HC(6)H(4)CO(2)H)(2).2H(2)O, respectively. ThF(2)(PO(3)C(6)H(4)CO(2)H) adopts a pillared structure constructed from thorium oxyfluoride layers built from [ThO(4)F(4)] units that are bridged by carboxyphenylphosphonate to yield a three-dimensional network. UO(2)(PO(3)HC(6)H(4)CO(2)H)(2).2H(2)O forms one-dimensional chains of UO(6) tetragonal bipyramids that are bridged by the phosphonate moiety of the ligand. The carboxylate portion of the structure links the chains together into layers via a hydrogen-bonding network. The higher effective charge and more isotropic coordination of the Th(IV) centers versus the uranium centers contained within uranyl cations allow for coordination by the protonated carboxylate portions of the ligands to the thorium cations, which does not occur with uranium in carboxyphosphonates. UO(2)(PO(3)HC(6)H(4)CO(2)H)(2).2H(2)O displays vibronically coupled fluorescence and the potential for energy transfer from the ligand to the charge-transfer bands of the uranyl cations. The main fluorescence by the ligand is quenched in ThF(2)(PO(3)C(6)H(4)CO(2)H).

Uranyl diphosphonates with pillared structures.

A series of five uranyl diphosphonates with pillared and canted pillared structures have been prepared and characterized. These compounds are constructed from UO(6) tetragonal bipyramids and UO(7) pentagonal bipyramids that are bridged by the diphosphonate anions. All of these compounds fluoresce at room temperature.