Implications of bond disorder in a S=1 kagome lattice.

Strong hydrogen bonds such as F···H···F offer new strategies to fabricate molecular architectures exhibiting novel structures and properties. Along these lines and, to potentially realize hydrogen-bond mediated superexchange interactions in a frustrated material, we synthesized [HF][NiF(Fpy)][SbF] (Fpy = 3-fluoropyridine). It was found that positionally-disordered HF ions link neutral NiF(Fpy) moieties into a kagome lattice with perfect 3-fold rotational symmetry.

Antiferromagnetism in a Family of S = 1 Square Lattice Coordination Polymers NiX2(pyz)2 (X = Cl, Br, I, NCS; pyz = Pyrazine).

The crystal structures of NiX2(pyz)2 (X = Cl (1), Br (2), I (3), and NCS (4)) were determined by synchrotron X-ray powder diffraction. All four compounds consist of two-dimensional (2D) square arrays self-assembled from octahedral NiN4X2 units that are bridged by pyz ligands. The 2D layered motifs displayed by 1-4 are relevant to bifluoride-bridged [Ni(HF2)(pyz)2]EF6 (E = P, Sb), which also possess the same 2D layers.

Soft chemical control of superconductivity in lithium iron selenide hydroxides Li(1-x)Fe(x)(OH)Fe(1-y)Se.

Hydrothermal synthesis is described of layered lithium iron selenide hydroxides Li(1-x)Fe(x)(OH)Fe(1-y)Se (x ∼ 0.2; 0.02 < y < 0.

Strontium vanadium oxide-hydrides: "square-planar" two-electron phases.

A series of strontium vanadium oxide-hydride phases prepared by utilizing a low-temperature synthesis strategy in which oxide ions in Sr(n+1)V(n)O(3n+1) (n=∞, 1, 2) phases are topochemically replaced by hydride ions to form SrVO2H, Sr2VO3H, and Sr3V2O5H2, respectively. These new phases contain sheets or chains of apex-linked V(3+)O4 squares stacked with SrH layers/chains, such that the n=∞ member, SrVO2H, can be considered to be analogous to "infinite-layer" phases, such as Sr(1-x)Ca(x)CuO2 (the parent phase of the high-T(c) cuprate superconductors), but with a d(2) electron count. All three oxide-hydride phases exhibit strong antiferromagnetic coupling, with SrVO2H exhibiting an antiferromagnetic ordering temperature, T(N)>300 K.