Uranyl Peroxide Oxalate Cage and Core–Shell Clusters Containing 50 and 120 Uranyl Ions

Cage clusters built from uranyl hexagonal bipyramids and oxalate ligands crystallize from slightly acidic aqueous solution under ambient conditions, facilitating structure analysis. Each cluster contains uranyl ions coordinated by peroxo ligands in a bidentate configuration. Uranyl ions are bridged by shared peroxo ligands, oxalate ligands, or through hydroxyl groups. U₅₀Ox₂₀ contains 50 uranyl ions and 20 oxalate groups and is a topological derivative of the U₅₀ cage cluster that has a fullerene topology. U₁₂₀Ox₉₀ contains 120 uranyl ions and 90 oxalate groups and is the largest and highest mass cluster containing uranyl ions that has been reported. It has a core–shell structure, in which the inner shell (core) consists of a cluster of 60 uranyl ions and 30 oxalate groups, identical to U₆₀Ox₃₀, with a fullerene topology. The outer shell contains 12 identical units that each consist of five uranyl hexagonal bipyramids that are linked to form a ring (topological pentagon), with each uranyl ion also coordinated by a side-on nonbridging oxalate group. The five-membered rings of the inner and outer shells (the topological pentagons) are in correspondence and are linked through K cations. The inner shell topology has therefore templated the location of the outer shell rings, and the K counterions assume a structure-directing role. Small-angle X-ray scattering data demonstrated U₅₀Ox₂₀ remains intact in aqueous solution upon dissolution. In the case of clusters of U₁₂₀Ox₉₀, the scattering data for dissolved crystals indicates the U₆₀Ox₃₀ core persists in solution, although the outer rings of uranyl bipyramids contained in the U₁₂₀Ox₉₀ core–shell cluster appear to detach from the cluster when crystals are dissolved in water

Uranyl Peroxide Oxalate Cage and Core–Shell Clusters Containing 50 and 120 Uranyl Ions

Cage clusters built from uranyl hexagonal bipyramids and oxalate ligands crystallize from slightly acidic aqueous solution under ambient conditions, facilitating structure analysis. Each cluster contains uranyl ions coordinated by peroxo ligands in a bidentate configuration. Uranyl ions are bridged by shared peroxo ligands, oxalate ligands, or through hydroxyl groups. U₅₀Ox₂₀ contains 50 uranyl ions and 20 oxalate groups and is a topological derivative of the U₅₀ cage cluster that has a fullerene topology. U₁₂₀Ox₉₀ contains 120 uranyl ions and 90 oxalate groups and is the largest and highest mass cluster containing uranyl ions that has been reported. It has a core–shell structure, in which the inner shell (core) consists of a cluster of 60 uranyl ions and 30 oxalate groups, identical to U₆₀Ox₃₀, with a fullerene topology. The outer shell contains 12 identical units that each consist of five uranyl hexagonal bipyramids that are linked to form a ring (topological pentagon), with each uranyl ion also coordinated by a side-on nonbridging oxalate group. The five-membered rings of the inner and outer shells (the topological pentagons) are in correspondence and are linked through K cations. The inner shell topology has therefore templated the location of the outer shell rings, and the K counterions assume a structure-directing role. Small-angle X-ray scattering data demonstrated U₅₀Ox₂₀ remains intact in aqueous solution upon dissolution. In the case of clusters of U₁₂₀Ox₉₀, the scattering data for dissolved crystals indicates the U₆₀Ox₃₀ core persists in solution, although the outer rings of uranyl bipyramids contained in the U₁₂₀Ox₉₀ core–shell cluster appear to detach from the cluster when crystals are dissolved in water

A. Relationship between modeled NPP and observed NPP. B. Relationship between modeled NPP and other evaluations.

<p>A. Relationship between modeled NPP and observed NPP. B. Relationship between modeled NPP and other evaluations.</p

Difference analysis of ecosystem service values (ESVs) in the national nature reserves in Ningxia in 2000, 2005 and 2010.

<p>Difference analysis of ecosystem service values (ESVs) in the national nature reserves in Ningxia in 2000, 2005 and 2010.</p

Areas of land use types in the national nature reserves in Ningxia in 2000, 2005, and 2010.

<p>Areas of land use types in the national nature reserves in Ningxia in 2000, 2005, and 2010.</p

Distribution of land use types during 2000–2010.

<p>Distribution of land use types during 2000–2010.</p

Distribution of weather stations.

<p>Distribution of weather stations.</p

Equivalent value per unit area of ecosystem services in China [26].

<p>Equivalent value per unit area of ecosystem services in China <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0089174#pone.0089174-Xie1" target="_blank">[26]</a>.</p

Dynamic rates of each land use type during 2000–2010.

<p>Dynamic rates of each land use type during 2000–2010.</p

Interaction of Ionic Liquids with a Lipid Bilayer: A Biophysical Study of Ionic Liquid Cytotoxicity

Ionic liquids (ILs) have been widely considered and used as “green solvents” for more than two decades. However, their ecotoxicity results have contradicted this view, as ILs, particularly hydrophobic ones, are reported to exhibit high toxicity. Yet the origin of their toxicology remains unclear. In this work, we have investigated the interaction of amphiphilic ILs with a lipid bilayer as a model cell membrane to understand their cytotoxicity at a molecular level. By employing fluorescence imaging and light and X-ray scattering techniques, we have found that amphiphilic ILs could disrupt the lipid bilayer by IL insertion, end-capping the hydrophobic edge of the lipid bilayer, and eventually disintegrating the lipid bilayer at high IL concentration. The insertion of ILs to cause the swelling of the lipid bilayer shows strong dependence on the hydrophobicity of IL cationic alky chain and anions and is strongly correlated with the reported IL cytotoxicity