Fa-Nian Shi

Structure, luminescence and magnetic properties of AgLnW2O8 (Ln = Eu, Gd, Tb AND Dy) compounds

Four new compounds AgLnW(2)O(8) (Ln = Eu, Gd, Tb and Dy) are prepared by solid-state reactions. They crystallize with a scheelite-related monoclinic symmetry. Infrared (IR) spectra show complicated absorption transitions in the region of 1000-400 cm(-1) that are similar to those of AgLnMo(2)O(8). Broad excitation and emission bands of the tungstate group are observed in AgGdW2O8 and AgTbW2O8 with a large Stokes shift, 12 573 and 12 387 cm(-1), respectively. Excitation and emission spectra of AgLnW(2)O(8) (Ln = Eu, Gd and Tb) show that energy transfer from the tungstate to EU3+, Gd3+ and Tb3+ occurs and that Eu3+ ions occupy a single crystallographic site with the C-2 Site symmetry

Highly emissive Zn–Ln metal–organic frameworks with an unusual 3D inorganic subnetwork

Mixed zinc-lanthanide (Zn-Ln) metal-organic frameworks (MOFs) based on the 3,5-pyrazoledicarboxylate ligand exhibit an unusual three-dimensional (3D) inorganic subnetwork and display highly efficient photoluminescence.

Mixed Cu(II)–Bi(III) metal organic framework with a 2D inorganic subnetwork and its catalytic activity

The very dense (d = 4.359 g cm−3) three dimensional (3D) hybrid heterometallic framework Bi3O2Cu(OH)(pdc)2 (pdc3−:3,5-pyrazoledicarboxylate), 1, features a 2D inorganic subnetwork representing an unprecedented topological type, and is an effective catalyst for the diastereoselective synthesis of E-α,β-unsaturated ketones.

Two dimensional porous 3d–4f heterometallic coordination polymers constructed by pyridine-2,3-dicarboxylic acid

Reactions of pyridine-2,3-dicarboxylic acid (pydcH2), cobalt acetate and lanthanide nitrate under hydrothermal conditions result in four new 3d–4f heterometallic coordination polymers, namely, [LnCo(pydc)3(H2O)3]·9H2O {Ln = Dy (1), Ho (2), Er (3) and Tm (4)}. All compounds were characterized by elemental analysis, IR spectroscopy, SEM, EDS, thermal gravimetric analysis and X-ray diffraction. The compounds feature a two dimensional (2-D) layer structure with large apertures, in which each pydc2− ligand links two metal centers and each metal center is bonded to three pydc2− and vice versa. The adsorption and catalytic properties of compound 1 were investigated.

Structure and luminescence properties of some newAgLnW2O8 compounds

Three new compounds, AgLnW 2 O 8 (Ln 3+ =Eu, Gd or Tb), have been prepared by a solid-state reaction and crystallize with a scheelite-related monoclinic symmetry. Their IR spectra show absorption transitions in the region 1000–400 cm -1 similar to KLnW 2 O 8 . Broad excitation and emission bands of the tungstate group with a large Stokes shift (12 573 cm -1 ) are observed in AgGdW 2 O 8 . Excitation and emission spectra of AgLnW 2 O 8 (Ln=Eu or Tb) show that energy transfer from tungstate to Eu and Tb occurs and that Eu 3+ ions occupy a unique crystallographic site with C 2 site symmetry.

Zeolite CAN and AFI-Type Zeolitic Imidazolate Frameworks with Large 12-Membered Ring Pore Openings Synthesized Using Bulky Amides as Structure-Directing Agents.

Using bulky amides as the structure-directing agents (SDAs) is an alternative synthetic strategy for the exploration of crystalline large pore (≥12-membered ring) zeolitic imidazolate frameworks (ZIFs). Specifically, by using the bulky amides, dibutylformamide (DBF) and dipropylformamide (DPF) as solvent and imidazole (Im) as a ligand, two ZIFs mimicking the CAN and AlPO-5 (AFI) zeotypes with 12-membered ring (MR) pore openings were synthesized, and denoted as CAN-[Zn(Im)2] and AFI-[Zn(Im)2], respectively. These two materials are the first known examples of Zn(Im)2 polymorphs with 12-MR pores and AFI-[Zn(Im)2] has the largest pore apertures reported to date for ZIF materials. The concept that the bulky amides used were not simply acting as the solvent, but were in fact acting as SDAs or templates during the synthesis of the large pore ZIFs, was suggested by the closeness of the geometrical fit between the guest DBF and the can cages (composite building units) of the CAN-[Zn(Im)2].

Calcium Phosphonate Frameworks for Treating Bone Tissue Disorders

Two new examples of uncommon three-dimensional Ca-bearing metal organic frameworks, [Ca(H2O)3(HPXBP)] (CaP1) and [Ca2(H2O)2(HPXBP)1.5] (CaP2) (PXBP: p-xylylenebisphosphonate), were prepared and their structures characterized by single crystal X-ray diffraction. CaP1 crystallizes in the monoclinic C2/c space group, with three water molecules occupying a half coordination sphere on one side of the Ca atom, while CaP2 crystallizes in the triclinic P1̅ space group, with two crystallographic unique Ca atoms, each coordinated by a single water molecule. In contrast with CaP2, which exhibits very low bioactivity, CaP1 readily precipitates bone-precursor phases (octacalcium phosphate, OCP, and hydroxyapatite) in SBF solutions. Moreover, studies with MG63 osteoblast-like cells indicate that CaP1 is not toxic and stimulates bone mineralization and, thus, holds considerable potential for treating bone diseases, such as osteoporosis.

Transposition of chirality from diphosphonate metal–organic framework precursors onto porous lanthanide pyrophosphates

Chiral porous inorganic materials, lanthanide pyrophosphates, were prepared from chiral porous metal-organic framework precursors, which upon thermal decomposition transpose their chirality and porosity onto the inorganic framework. It is argued that this synthesis concept may be extended to other chiral porous inorganic solids.

Crystal structure, topology, tiling and photoluminescence properties of 4d–4f hetero-metal organic frameworks based on 3,5-pyrazoledicaboxylate

Reaction of lanthanide oxides, cadmium acetate and 3,5-pyrazoledicarboxylic acid under hydrothermal conditions afforded five new isostructural 4d–4f hetero-metal organic frameworks, [Cd3Ln(pdc)3(H2O)] {H3pdc = 3,5-pyrazoledicarboxylic acid, Ln = La (1), Pr (2), Nd (3), Sm (4) and Eu (5)}. All compounds were characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy. The compounds feature a very interesting 3D structure built up from a secondary building unit, [Cd12Ln8(pdc)6], and possess a new topology type and complicated unique tiling. The solid state photoluminescence properties of compounds 3–5 were investigated at room temperature.

Syntheses, crystal structures and magnetic properties of two honeycomb-layered bimetallic assemblies, K2[NiII(cyclam)]3[FeII(CN)6]2 · 12H2O and [NiII(cyclam)]3[FeIII(CN)6]2 · 16H2O

Two bimetallic assemblies, K2[NiII(cyclam)]3[FeII(CN)6]2 · 12H2O (1) and [NiII(cyclam)]3[FeIII(CN)6]2 · 16H2O (2) (cyclam = 1,4,8,11-tetraazacyclotetradecane), were obtained by reaction of K4[Fe(CN)6] and [Ni(cyclam)](ClO4)2 in aqueous media at different temperatures. Their crystals were structurally determined and magnetic properties were studied. Both of the compounds have honeycomb-layered structures, which are formed by Fe6Ni6 units linked through the cyanide bridges. Structure (1) consists of polyanions containing NiII–N≡C–FeII linkages and K+ cations, while structure (2) is a two-dimensional neutral layer containing NiII–N≡C–FeIII linkages. The magnetic properties of (1) and (2) have been investigated in the 5–300 K range. Compound (1) exhibits a weak antiferromagnetic interaction with Weiss constant Θ = −0.35 K; compound (2) shows ferromagnetic intralayer and antiferromagnetic interlayer interactions.