Syntheses and characterizations of a series of heptanuclear octahedral polyhedra {LnNi6} with different amino acids as ligands in aqueous media

Inorganic open framework based on lanthanide ions and polyoxometalates with high proton conductivity

The development of new proton-conducting materials that are cost effective and have high proton conductivity and water stability is very important in fuel cell technology.

Crystal structure of an unknown solvate of dodecakis-(μ2-alaninato-1:2κ(2) O:N,O)cerium(III)hexa-nickel(II) aqua-tris-(hydroxido-κO)tris-(nitrato-κ(2) O,O')cerate(III)

The chiral title compound, [CeNi6(C3H6NO2)12][Ce(NO3)3(OH)3(H2O)], comprises a complex heterometallic Ni/Ce cation and a homonuclear Ce anion. Both the cation and anion exhibit point group symmetry 3. with the Ce(III) atom situated on the threefold rotation axis. The cation metal core consists of six Ni(II) atoms coordinated in a slightly distorted octa-hedral N2O4 configuration by N and O atoms of 12 deprotonated l-alaninate ligands exhibiting both bridging and chelating modes. This metal-organic coordination motif encapsulates one Ce(III) atom that shows an icosa-hedral coordination by the O-donor atoms of the l-alaninate ligands, with Ce-O distances varying in the range 2.455 (5)-2.675 (3) Å. In the anion, the central Ce(III) ion is bound to three bidentate nitrate ligands, to three hydroxide ligands and to one water mol-ecule, with Ce-O distances in the range 2.6808 (19)-2.741 (2) Å. The H atoms of the coordinating water mol-ecule are disordered over three positions due to its location on a threefold rotation axis. Disorder is also observed in fragments of two l-alaninate ligands, with occupancy ratios of 0.608 (14):0.392 (14) and 0.669 (8):0.331 (8), respectively, for the two sets of sites. In the crystal, the complex cations and anions assemble through O-H⋯O and N-H⋯O hydrogen bonds into a three-dimensional network with large voids of approximately 1020 Å(3). The contributions of highly disordered ethanol and water solvent mol-ecules to the diffraction data were removed with the SQUEEZE procedure [Spek (2015 ▸). Acta Cryst. C71, 9-18]. The given chemical formula and other crystal data do not take into account the unknown amount of these solvent mol-ecules.

Syntheses, structures, and properties of a series of novel high-nuclear 3d–4f clusters with mixed amino acids as ligands: {Ln6Cu24}(Ln = Gd, Tb, Pr and Sm)

The first examples of high-nuclear 3d–4f heterometallic clusters {Ln₆Cu₂₄}(Ln = Gd, Tb, Pr and Sm) with mixed amino acid ligands are reported.