One-Dimensional Vanadium(III) Chalcogenidostannates Incorporating [V(tepa)]3+ Complexes as Bridging Groups

One-Dimensional Selenidostannates Based on an Infrequent Tetrameric Cluster [Sn4Se12] Exhibiting Electro-Catalytic Properties

The discovery of low-cost and efficient electro-catalytic materials for hydrogen evolution reaction (HER) is very desirable in hydrogen energy technology. Here, a new type of one-dimensional (1-D) organic hybrid selenidostannate [Ni(en)₃]_n[Sn₂Se₅]_n (SnSe-1, en = ethylenediamine) with an in situ [Ni(en)₃]²⁺ complex was achieved by the solvothermal reaction of Sn, Se, and NiCl₂·6H₂O in a mixed solvent of en and triethanolamine at 160 °C for 10 days. The crystal structure of SnSe-1 contains a unique 1-D [Sn₂Se₅^2-]_n chain built up from the sharing-edge connection of a hitherto-unknown tetrameric [Sn₄Se₁₂] cluster, which is separated by discrete [Ni(en)₃]²⁺ complexes. SnSe-1 is first combined with Ni nanoparticles supported on conductive porous Ni foam (NF) to constitute a Ni/SnSe-1/NF electrode as the HER electro-catalyst, displaying superior electro-catalytic activity in near-neutral conditions.

Magnetic anisotropy of transition metal and lanthanide ions in pentagonal bipyramidal geometry

The magnetic anisotropy associated with a pentagonal bipyramidal (PBP) coordination sphere is examined on the basis of experimental and theoretical investigations. The origin and the characteristics of this anisotropy are discussed in relation to the electronic configuration of the metal ions. The effects of crystal field, structural distortion, and a second-coordination sphere on the observed anisotropies for transition meal and lanthanide ions are outlined. For the Ln derivatives, we focus on compounds showing SMM-like behavior (i.e. slow relaxation of their magnetization) in order to highlight the essential chemical and structural parameters for achieving strong axial anisotropy. The use of PBP complexes to impart controlled magnetic anisotropy in polynuclear species such as SMMs or SCMs is also addressed. This review of the magnetic anisotropies associated with a pentagonal bipyramidal coordination sphere for transition metal and lanthanide ions is intended to highlight some general trends that can guide chemists towards designing a compound with specific properties.

Vanadium O-Centered Selenoiodide Complex: Synthesis and Structure of V4O(Se2)4I6·I2

The first vanadium selenoiodide V₄O(Se₂)₄I₆·I₂ was synthesized at a moderate temperature of 220 °C from V, Se, I₂, and water. Its crystal structure (tetragonal space group P4₂/nbc, a = 11.838(1) Å, c = 18.689(1) Å) contains O-centered vanadium(IV) tetranuclear fragment [V₄(μ₄-O)(μ₂-Se₂)₄(μ₂-I)₂I₄], where the edges of the distorted tetrahedron V₄ are bridged by four diselenide (Se₂)^2- and two iodide ligands; four terminal iodides coordinate V atoms additionally. This type of complex is known for Ti, Nb, and Ta but is new for vanadium. Magnetic susceptibility measurements of V₄O(Se₂)₄I₆·I₂ showed four unpaired electrons on vanadium atoms at room temperature and drop of the effective magnetic moment at cool down, presumably due to partial electron pairing. Probability of this transition to the diamagnetic state is in accord with the calculated electronic structure.

Synthesis, structure, and magnetic properties of the quaternary oxysulfides Ln 5V3O7S6 (Ln = La, Ce)

Two rare earth oxysulfides Ln 5V3O7S6 (Ln = La, Ce) have been synthesized and their structures determined. The two isostructural compounds crystallize in the orthorhombic space group Pmmn (no. 59). The structure features one-dimensional edge-sharing VS4O2 octahedron chains parallel to the b axis. The bonding between V and S/O is covalent, and between Ln 3+ and the rest of the matrix ionic. Magnetic susceptibility measurement revealed that V is in a mixed valence state of V3+ and V4+. Its magnetic behavior follows the Curie-Weiss law.

An Organic Hybrid Indium-Telluride Incorporating Binuclear Complexes [In2(ea)4]2+ with a Bridging Oxygen Donor

The new organic hybrid indium-telluride [In₂(ea)₂Te₂]_n (1; Hea = ethanolamine) exhibits a new type of one-dimensional polymeric chain based on the linkages of dinuclear [In₂(ea)₄]²⁺ and [In₂Te₄]^2- units, which offers the first example of an indium-telluride framework incorporating binuclear complexes [In₂(ea)₄]²⁺ with a bridging O donor. 1 shows a distinctive photocurrent response and photocatalytic properties under visible-light illumination.