A three-dimensional gadolinium organic framework based on a pyridinedicarboxylic acid organic linker with a paddle-wheel-type network structure

A new gadolinium(III)–pyridine-2,5-dicarboxylic acid (GdIII–2,5-H2pdc)-based three-dimensional coordination polymer, namely, poly[dimethylazanium [bis(μ-pyridine-2,5-dicarboxylato)gadolinium(III)]], {[(CH3)2NH2][Gd(C7H3NO4)2]} n , CP-1, has been synthesized via a typical solvothermal method. The as-synthesized material was characterized in the solid state using single-crystal X-ray diffraction, powder X-ray diffraction, thermogravimetric analysis and FT–IR spectroscopy. During the synthesis of CP-1, the in situ dimethylformamide (DMF) promotes the formation of a dimeric unit and these act as secondary building blocks in the assembly of a three-dimensional anionic {[Gd(pdc)2]−}∞ framework. The framework has channels along the c axis which are filled by dimethylazanium cations. Interestingly, the framework shows a helical-type assembly running down the a axis. A Hirshfeld surface analysis of CP-1 suggests that extra stability is provided by hydrogen-bonding interactions. The magnetic properties of CP-1 showed weak antiferromagnetic couplings between adjacent Gd3+ ions.

Colloidal synthesis of metal chalcogenide nanomaterials from metal-organic precursors and capping ligand effect on electrocatalytic performance: progress, challenges and future perspectives

Renewable and sustainable functional nanomaterials, which can be employed in alternative green energy sources, are highly desirable. Transition metal chalcogenides are potential catalysts for processes resulting in energy generation and storage. In order to optimize their catalytic performance, high phase purity and precise control over shape and size are indispensable. Metal-organic precursors with pre-formed bonds between the metal and the chalcogenide atoms are advantageous in synthesizing phase pure transition metal chalcogenides with controlled shape and sizes. This can be achieved by the decomposition of metal-organic precursors in the presence of suitable surfactants/capping agents. However, the recent studies on electrocatalysis at the nanoscale level reveal that the capping agents attached to their surface have a detrimental effect on their efficiency. The removal of surfactants from active sites to obtain bare surface nanoparticles is necessary to enhance catalytic activity. Herein, we have discussed the properties of different metal-organic precursors and the role of surfactants in the colloidal synthesis of metal chalcogenide nanomaterials. Moreover, the effect of surfactants on their electrocatalytic performance, the commonly used strategies for removing surfactants from the surface of nanomaterials and the future perspectives are reviewed.

Synthesis, structure and the Hirshfeld surface analysis of three novel metal-tiron coordination complexes

Three novel metal-tiron (4,5-dihydroxy-1,3-benzenedisulfonic acid disodium salt) and other pillared ligand bpy (4,4′-bipyridyl)-centered coordination polymers of the formulae [Cd(tiron)(bpy)₂(H₂O)₂]·0.5(H₂O), 1, [Co₃(tiron-bpy)₂(bpy)(H₂O)₈]·(H₂O)₂, 2, and [Ba₂(tiron-bpy)₂(H₂O)₄][solvent], 3, were successfully synthesized under hydrothermal conditions. The as-synthesized materials were well characterized by complimentary techniques such as single-crystal X-ray diffraction, powder X-ray diffraction, Fourier-transform infrared spectroscopy and thermogravimetric analysis techniques. The as-synthesized coordination polymers of 1 and 2 featured 1D chains, while 3 shows a layered structure. Co-based 2 shows linear trinuclear Co(ii) ions and these Co(ii) ions have antiferromagnetic interactions among themselves. The structure of 1 features a zig-zag chain formed by the linkage between monodentate tiron ligands and octahedral Cd(ii) ions, interconnected by a twisted bpy ligand, 2 shows a linear chain constructed from corner-sharing trinuclear octahedral Co(ii) ions and coordinated with a tridentate tiron-bpy adduct ligand, whereas 3 shows nona-coordinated Ba(ii) ions sharing edges with other Ba(ii) ions and connected by hexadentate tiron-bridged structures resulting in a layered structure. In 2 and 3, the bpy nitrogen attacks at the ortho position of the tiron ligand and forms an in situ ligand adduct. The central metal ions show an octahedral geometry in 1 (Cd(ii) ions) and 2 (Co(ii) ions), but nona-coordination of Ba(ii) ions in 3. The short interatomic interactions in the crystal structures were evaluated by mapping the Hirshfeld surface process using pseudo-mirrored 2D fingerprint plots. The major short interatomic interactions H⋯H, O⋯H and C⋯H cover the Hirshfeld surfaces.

Three novel metal-tiron (4,5-dihydroxy-1,3-benzenedisulfonic acid disodium salt) and other pillared ligand bpy (4,4-bipyridyl) centered coordination polymers were successfully synthesized and characterized.

High proton conductivity behavior in a 2D metal sulfite constructed from a histidine ligand

In the presence of the amino acid histidine, an inorganic–organic hybrid metal sulfite, Zn₂(SO₃)₂(C₆N₃O₂H₉)₂·H₂O (1), has been prepared under hydrothermal conditions. Single-crystal X-ray diffraction analysis reveals that 1 shows a 2D layer framework built up from a classical second building unit (S4R), and bridged histidine molecule. Notably, it is the first report of a metal sulfite in the presence of an amino acid molecule. A 1D H-bonding array can be constructed by the H-bonding interaction between histidine molecules and sulfite groups. Moreover, a new function of metal sulfite for proton conduction was investigated by alternating-current impedance analysis. The results demonstrate that compound 1 shows a high proton conductivity of approximately 10⁻³ S cm⁻¹ at 348 K and 98% relative humidity.

In the presence of the amino acid histidine, an inorganic–organic hybrid metal sulfite (compound 1), has been prepared under hydrothermal conditions. Compound 1 shows a high proton conductivity of, approximately 10⁻³ S cm⁻¹ at 348 K and 98% RH.

Hybrid materials based on transition metal–BTC–benzimidazole: solvent assisted crystallographic and structural switching

Five transition metal–BTC–BIm based coordination polymers with hierarchical structures were synthesized under hydro/solvothermal condition. Crystal structure analysis of the compounds showed that 1 forms a 1D chain, 2 and 3 have 2D layers, while 4 and 5 have three-dimensional architectures.

Organically templated inorganic-organic hybrid metal (Zn and Cd) Sulfite-oxalates with layered and three-dimensional structures

We report single crystal X-ray investigations of three d¹⁰ metal based oxalate-sulfite inorganic-organic hybrid open framework materials, namely [Zn₂(SO₃)₂(C₂O₄)_0.5(C₆N₂H₁₃)]·(H₂O)₂, 1, [C₄N₂H₁₂]_0.5[Zn₂(SO₃)₂(C₂O₄)_0.5(H₂O)₂], 2 and [C₄N₂H₁₂][Cd₂(SO₃)₂(C₂O₄)(H₂O)]·H₂O, 3 which show layered and three dimensional structures with different organic templates. These materials were synthesized under hydrothermal conditions and characterized by techniques such as single crystal X-ray diffraction, dipole moment calculations, FTIR, powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The common feature for 1 and 2 is the interconnection of embedded zinc-sulfite chains via oxalate anions in the framework and in 3, cadmium-oxalate chains are interconnected via sulfite anions. The coordination geometries of metal(ii) ions vary significantly resulting in a ladder-like layered structure in the case of 1, a 3D framework in case of 2 and a layered structure with an embedded one-dimensional channel in 3. The observed structures can also be partly attributed to the influence exerted by the presence of different structure directing agents (SDA) in the lattice. The dipole moments for metal polyhedra 1, 2 and 3 were calculated from bond valence analyses and are 2.39 D for Zn(1)O₄N polyhedra and 1.66 D for Zn(2)O₄ polyhedra in 1, 24.90 D for Zn(1)O₆ and 29.52 D for Zn(2)O₄ in 2 and 5.82 D for Cd(1)O₇ and 2.90 D for Cd(2)O₆ in 3.

Two hybrid transition metal triphosphonates decorated with a tripodal imidazole ligand: synthesis, structures and properties

Two transition-metal triphosphonates with pillar-layered structures were synthesized and characterized. The luminescence, magnetic and proton conductive properties were investigated.

Organic–inorganic hybrid three-dimensional metal sulfite-oxalates with honeycomb-like structures

The crystallographic signatures and characterization of two novel mixed metal hybrid open-frameworks [Na₂Mn₂(C₂O₄)(SO₃)₂(H₂O)₂], 1 and [NaEu(C₂O₄)(SO₃)(H₂O)₃], 2 are reported for the first time; they are synthesized under hydrothermal conditions to generate 3D assemblies and honeycomb-like structures.

Multicomponent self-assembly of a pentanuclear Ir–Zn heterometal–organic polyhedron for carbon dioxide fixation and sulfite sequestration

An iridium-containing pentanuclear metal–organic polyhedron was constructedviaa subcomponent self-assembly. The three equatorial Zn(ii) ions in the structure induced atmospheric carbon dioxide transformation as carbonate and sulfur dioxide as sulfite with bonding to the three metal centers.