The 3D porous metal-organic framework constructed by Cd(II) with 2-methylimidazole-4,5-dicarboxylic acid

Abstract  

A 3D metal-organic framework, [C₆H₃CdN₂O₄]·NH₄, was synthesized solvothermally and structurally characterized by single-crystal X-ray structure determination. This compound crystallizes in the tetragonal system with the space group P42/nmc. The crystal structure presents a 3D framework and open channels, exhibiting guest-coordination sites at channel walls and strong fluorescent emission.     

Two luminescent complexes constructed from different metals with pyridine-2,4-dicarboxylic acid (H2PDC)

Two coordination complexes, [Mg(HPDC)₂(H₂O)₂] (1) and [Dy(PDC)₂(H₂O)₂]·5H₂O·NH₄ (2), were synthesized under hydrothermal conditions. The structures and fluorescent properties of the complexes were studied by elemental analysis, IR, thermal analysis, powder X-ray diffraction, and X-ray crystallography. In 1, Mg(II) coordinated with six oxygens from H₂PDC and water. For 2, there were NH₄ ⁺ ions in the holes of the metal quarternary rings to balance electronic charges. Compared to 1, 2 constructed from Dy(III) had larger void space and potential applications on gas adsorption. The two complexes show similar fluorescence in the visible region.     

Syntheses,structure and characterization of a fourfold interpenetrated 3D Cd(II) organic framework constructed with a zwitterionic ligand

A 3-D cadmium(II) organic framework with a fourfold interpenetrated diamond topological structure, {[CdLBDC]·(H₂O)₂}_n (1), was synthesized through zwitterionic ligand H₃LBr₃ (1,1′,1″-(2,4,6-trimethylbenzene-1,3,5-triyl)-tris(methylene)tris(4-carboxypyridinium)tribromide), secondary ligand H₂BDC (1,4-benzenedicarboxylic acid) and Cd(NO₃)₂·4H₂O by solvothermal method. Compound 1 was characterized by elemental analyses, FT-IR spectroscopy, powder, and single-crystal X-ray diffraction and thermogravimetric analysis. The photophysical properties of 1 were investigated by solid-state diffuse reflectance spectrum. In 1, each L is linked by two separate Cd(II)-centered distorted tetrahedra, which are also linked by two L, thereby forming a head-to-tail connected 2-D layer structure and further building the 3-D framework through BDC^2?-chelating-bridging between layers.     

Two new 3D metal-organic frameworks of nanoscale cages constructed by Cd(II) and conformationally-flexible cyclohexanehexacarboxylate

Hydrothermal reactions of Cd(NO3)2.4H2O with a,e,a,e,a,e-1,2,3,4,5,6-cyclohexanehexacarboxylic acid (H6L(I)) generate two new 3D MOFs with nanoscale cages, in which the L(I) ligand in the first MOF transforms its conformation to the e,e,e,e,e,e form while the L(I) ligand in the second MOF transforms its conformation to mixed e,e,e,e,e,e and e,e,e,e,a,a forms in a 1 : 3 ratio, showing the effect of the auxiliary sodium ion on stabilizing the intermediate conformations and on the construction of the heterometallic MOF structure.     

A pillar-layered Cd(II) metal-organic framework for selective detection of organic explosives

The detection of explosives is crucial for homeland security, environmental cleaning, and military issues. As a new class of porous materials, metal-organic frameworks (MOFs) are promising platforms for the detection of organic explosives. In this work, a new pillar-layered Cd(II) MOF, [CdL_0.5dpe_0.5]·2H₂O (BUT-202, H₄L = 4,8-disulfonaphthalene-2,6-dicarboxylic acid, dpe = 1,2-bis(4-pyridyl)ethylene), was synthesized and characterized by single-crystal X-ray diffraction, powder X-ray diffraction, thermogravimetric analysis, infrared spectroscopy, and elemental analysis. BUT-202 has good fluorescent properties, which can be selectively quenched by trace amounts of 2,4,6-trinitrophenol (TNP) in DMF with low detection limit of 0.2 μM.     

A 3-D metal-organic framework constructed with cobalt(II), 1,3-di(4-pyridyl)propane (bpp) and 3,5-dinitrobenzoate (DNBA) with methyl-3,5-dinitrobenzoate (MDNBA) by in-situ synthesis as a guest

A new 3-D cobalt(II) mixed ligand, metal-organic framework {[Co₂(bpp)₂(DNBA)₄H₂O] ·?MDNBA} (1), (bpp =?1,3-di(4-pyridyl)propane, DNBA =?3,5-dinitrobenzoate and MDNBA =?methyl-3,5-dinitrobenzoate) was synthesized in aqueous-methanol medium. X-ray structural analysis of 1 revealed that the dinuclear cobalt clusters interlinked by two μ-carboxylates and a μ ₂ water molecule, acting as a node, are connected to four other clusters through bridging bpp to generate an extended neutral 3-D network. MDNBA was in-situ synthesized and encapsulated in the framework as a guest molecule. Moreover, the fluorescence spectrum shows 1 exhibits blue fluorescent emission in the solid state at room temperature.     

Hydrothermal synthesis,structure,fluorescence property of a novel 3D metal-organic framework with high thermal stability

A novel 3D metal-organic framework(MOF) with remarkable thermal stability,Ni(BIC)2.2·5H2O(JUC-86)(HBIC = 1-H-benzimidazole-5-carboxylic acid and JUC = Jilin University China),has been synthesized under hydrothermal conditions.It crystallizes in tetragonal symmetry with P43212 space group.The 3D structure consists of channels assembled from triple helices with a 4.5 × 4.52 aperture,which are formed by the parallel alignment of three infinite helical chains.The thermogravimetric analysis(TGA) and powder X-ra...     

Novel 3D metal-organic framework with Prussian Blue topology: [Mn(HCOO)3]n·xnH2O

A novel complex, [Mn(HCOO)₃]_n·xnH₂O, has been synthesized and studied by X-ray crystallography. The structure is trigonal, space group R-3c, a = 8.327(1) Å, c = 22.890(6) Å, V = 1374.4(5) ų, Z = 6; final R = 0.045. The crystal structure reveals both O-atoms of the formic acid ligand coordinated to Mn(III) to form a three-dimensional porous framework with the topology of Prussian Blue.     

Synthesis and Structure of a POMs-based 3D Zeolike Ionic Crystal, {[Co（dpdo）2（H2O）2（CH3CN）]2（SiMo12O40）（H2O）2}n

A POMs-based 3D zeolike ionic crystal 1, {[Co（dpdo）2（CH3CN）（H2O）2]2（SiMo12O40）- （HEO）2}n （dpdo = 4,4＇-bipyridine-N,N＇-dioxide）, was constructed via self-assembly by embedding Keggintype [SiMo12O40]^4- polyanions within the intercrystalline voids as pillars and structurally characterized. The crystal structure was determined by single-crystal X-ray diffraction. The crystal is of triclinic, space group P1 with a = 11.430（3）, b = 12.242（3）, c = 14.279（3）A, α = 106.196（4）,β = 94.316（4）, γ = 98.294（3）°, V = 1884.5（7）A^3 Z = 1, C44H50N10O54CoEMo12Si, Mr = 2880.17, Dc = 2.538 g/cm^3, p = 2.484 mm^-1,F（000） = 1388, the final R = 0.0383 and wR = 0.1096 for 7753 observed reflections with I 〉 2σ（I）. Flack factor is 0.22（3）. Compound 1 is a pillar-layered framework with the [SiMo12O40]^4- anions linearly located on the square voids between the 2D bilayers which are formed by the dpdo ligands and cobalt（II） ions.     

Nickel(II)-azido ferromagnetic chains in a 3D porous metal-organic framework with breathing guest molecules

A new 3D porous Ni(II)-azido complex has been synthesized and characterized and exhibits guest sorption properties explored by single-crystal to single-crystal transformations and linear ferromagnetic chains held together by a Ni-isonicotinate framework.     

Synthesis of polycarbonate diol catalyzed by metal-organic framework Zn_4O[CO_2-C_6H_4-CO_2]_3

The metal-organic framework Zn4O[1,4-benzenedicarboxylate]3(Zn4O[CO2-C6H4-CO2]3,commonly known as MOF-5,was prepared by the ultrasonic irradiation method.The catalyst was characterized by X-ray diffraction(XRD) and Fourier transform infrared(FTIR) spectroscopy.It was then used as the catalyst for the preparation of polycarbonate diol(PCDL) via the transesterification between diphenyl carbonate(DPC) and 1,6-hexandiol(1,6-HD).Its catalytic activity in the transesterification process is evaluated by the yield ...     

A new 1D chiral metal-organic coordination polymer constructed by Cu(II) with L-3-Cyanophenylalanine

A new 1D chiral metal-organic coordination polymer [Cu(Cphe)₂] · 3H₂O (I) (HCphe = L-3-Cyanophenylalanine) has been synthesized in an aqueous solution and characterized by elemental analysis, thermogravimetric analysis (TGA), X-ray powder diffraction (XRPD), infrared spectroscopy (IR) and single crystal X-ray diffraction. The X-ray diffraction analysis reveals that I crystallizes in the monoclinic space group P2₁. The adjacent copper(II) atoms are linked by Cphe ligands to form a 1D zigzag chain, which is further connected via strong hydrogen bonds to form a 3D supramolecular framework. The unit cell parameters for I are: a = 12.0201(8), b = 6.1495(4), c = 14.8576(10) Å, β = 94.1720(10)°, V = 1095.00(13) ų, and Z = 2.     

Alkyldiamine bis(selenocyanato)cadmium(II) complexes: Synthesis, Cd, Se, N and C NMR spectroscopy and X-ray structure of a 2D metal-organic framework

Complexes of cadmium(II)-selenocyanate with several alkyldiamine ligands have been synthesized and characterized by IR, ¹¹³Cd, ⁷⁷Se, ¹⁵N and ¹³C NMR spectroscopy. The X-ray structure of the complex [Cd(SeCN)₂-en] reveals two non-equivalent metal ion centers, both with a distorted octahedral geometry. The combined bridging modes of selenocyanate and ethylenediamine with the blocking mode of a chelating ethylenediamine generate a 2D metal-organic framework.     

Computer‐Assisted 3D Structure Elucidation (CASE‐3D): The Structural Value of 2JCH in Addition to 3JCH Coupling Constants

We present a method to use long‐range CH coupling constants to derive the correct diastereoisomer from the molecular constitution of small molecules. A set of 79 ²J_CH and ³J_CH values collected from a single HSQMBC experiment on a sample of strychnine were used in the CASE‐3D (computer‐assisted 3D structure elucidation) protocol. In addition to the most commonly used ³J_CH coupling constants, the subset of 32 ²J_CH values alone showed an excellent degree of configuration selection. The study is mainly based on comparison of DFT‐calculated ^2,3J_CH values with experimental ones, critical for the case of ²J_CH. But the configuration selection also works well using ³J_CH values predicted from a semi‐empirical Karplus‐based equation limited to H?C?C?C fragments. The robustness, shown using strychnine as a proof of concept, makes the J‐based CASE‐3D analysis a viable option for the application in fields such as peptide and carbohydrate research, organic synthesis, natural‐product identification and analysis, as well as medicinal chemistry.     

Coexistence of water dimer and hexamer clusters in 3D metal-organic framework structures of Ce(III) and Pr(III) with pyridine-2,6-dicarboxylic acid

Ce(NO3)3.6H2O or Pr(NO3)3.6H2O and pyridine-2,6-dicarboxylic acid form a linear coordination polymeric structure under hydrothermal conditions. Hexameric water clusters join these linear chains through bonding to the metal ions. Other coordinated water and the carboxylate oxygen form an intricate array of hydrogen bonding resulting in a 3D network where each metal ion shows 9-coordination with an approximate D3 symmetry. Dimeric water clusters are also located in the void spaces. In the structure containing Pr(III), the water dimers are hydrogen-bonded to the hexamers, whereas in the Ce(III) structure, the dimers and the hexamers are far apart.     

Synthesis and 2D H-bonded Cd（ Ⅱ ） Network Structure of [Cd（C10H15N3）Cl2]

1 INTRODUCTION Transition metal Schiff base complexes have been extensively studied in the past two decades for their various crystallographic features, enzymatic reactions, steric effects[1～4], catalysis and magnetic properties[5, 6] as well as their important role in organisms[7, 8]. Most of these first-row materials are biologically essential with a number of their complexes showing bioactivities[9, 10]. Herein we describe the synthesis and X-ray structure of the cadmium (Ⅱ) compl…     

Two zinc(II) complexes based on indole-3-acetic acid: crystal structures,fluorescence sensors,and ion exchange with mercury(II)

Two new coordination complexes, [Zn(IA)₂(phen)] (1) and [Zn(IA)₂(4,4′-bipy)] _n ?·?C₂H₅OH (2) (IAH?=?indole-3-acetic acid, phen?=?1,10-phenanthroline, 4,4′-bipy?=?4,4′-bipyridine), have been prepared and characterized by single-crystal X-ray diffraction. Complex 1 is mononuclear and 2 presents a 1-D zigzag chain, in which 4,4′-bipy connects the Zn(II) ions. Both complexes show fluorescence emissions and exhibit fluorescence quenching when Hg²⁺ ions are present. ICP, EDS, and SEM experiments reveal that zinc in both complexes can be exchanged by toxic mercury ions.     

A novel 4.6 5-connected metal-organic framework with strong fluorescent emission constructed by m-thioacetatebenzoic acid

A novel uninodal 5-connected metal-organic framework (MOF), [Cd₂L₂(4,4′-bipy)_3/2(H₂O)₂]_n (H₂L=m-thioacetatebenzoic acid and 4,4′-bipy=4,4′-bipyridine), was prepared under hydrothermal condition. It features an unusual brick-wall shape layer by 4,4′-bipy, which consists of right- and left-handed helical chains arrayed alternatively and finally expands by L^2- to a rare 5-connected nov (4⁴.6⁶) topology network. Photoluminescence study reveals that it displays intense structure-related fluorescent emission bands (λ_ex=355 nm) at 450 nm in the solid state at room temperature.     

Lead(II) coordination frameworks with 3-fluorophthalic acid: hydrothermal synthesis,crystal structure,and luminescence

Hydrothermal reactions of Pb(NO₃)₂ and 3-fluorophthalic acid (H₂Fpht) in the absence or presence of 2,2′-bipyridine (bpy) gave two coordination polymers: Pb₅(Fpht)₄(Fba)₂ (1) and [Pb₂(Fpht)₂(bpy)(H₂O)]·3H₂O (2). The 3-fluorobenzoic acid (HFba) results from an in situ decarboxylation of H₂Fpht. Solid 1 displays a 2-D structure, comprising center-related hexanuclear [Pb₃(COO)₆]₂ units. There are three crystallographically different Pb(II) ions and two different ligands, Fpht and Fba. The Fpht ligands adopt μ_6?:?η⁵η³ and μ_6?:?η³η⁴ unusual bridging coordination modes. A 3-D supramolecular architecture is formed via C–H?F hydrogen bonds. Solid 2 possesses a 1-D chain structure, comprising center-related tetranuclear [Pb₂(COO)₄]₂ units. There are two crystallographically different Pb(II) ions. The Fpht ligands adopt μ_3?:?η²η³ and μ_4?:?η³η³ bridging coordination. The free water molecules form (H₂O)₃ clusters to link the 1-D chain by hydrogen bonds. A 3-D supramolecular assembly is constructed via hydrogen bonds between the free water and the F of Fpht ligands. Fluorescence of the complexes originates from π*–π transitions of the ligands.