Structural Change and Radical Generation of a Cadmium-Based Metal-Organic Framework Induced by an Electric Field.

Herein we report the structural change and radical generation of a cadmium-based metal-organic framework (Cd-MOF) induced by external electric fields. Under a weaker single electric field, different coordination modes of Cd-L lead to 3D → 2D structural change. Under stronger superposed electric fields, Cd-MOF was excited to produce a stable free radical.

Cd-MOF: specific adsorption selectivity for linear alkyne (propyne, 2-butyne and phenylacetylene) molecules.

The selective adsorption of APPT-Cd-MOF 1 for propyne, 2-butyne and phenylacetylene was confirmed by single-crystal analysis. In addition, the selective adsorption performance of Cd-MOF for CH/CH/CH was investigated. The matching of the functionality and size/shape between porous materials and guest molecules clarified the specific recognition of 1 for linear alkyne molecules.

Rational Design of High-Relaxivity Eu -Based Contrast Agents for Magnetic Resonance Imaging of Low-Oxygen Environments.

Metal-based contrast agents for magnetic resonance imaging present a promising avenue to image hypoxia. Eu -based contrast agents have a unique biologically relevant redox couple, Eu , that distinguishes this metal for use in hypoxia imaging. To that end, we investigated a strategy to enhance the contrast-enhancing capabilities of Eu -based cryptates in magnetic resonance imaging by controlling the rotational dynamics.

Photochromic Rhenium-Based Molecular Rectangles: Syntheses, Structures, Photophysical Properties, and Electrochemistry.

Two novel -Re(CO)-based rectangles {[(CO)Re(μ-Cl)Re(CO)](μ-L)} () and {[(CO)Re(μ-OCH)Re(CO)](μ-L)}() based on new photochromic dithienylethene-containing ligand 2,7-di(pyridin-4-yl)-9,10-bis(5-chloro-2-methylthien-3-yl)-phenanthrene () were prepared. They displayed varying photochromic properties both in solution and in the single-crystal state. Through a judicious choice of the bridging ligands along the short sides of the rectangles, the photophysical and electrochemical properties of the complexes could also be readily tuned.

Syntheses of four porous 3-D Cd(ii) metal-organic frameworks from a new multidentate ligand 5-(imidazol-1-yl)--(pyridin-4-ylmethylene) nicotinohydrazide and their characterization and adsorption properties.

Herein, a new multidentate ligand, 5-(imidazol-1-yl)-(pyridin-4-ylmethylene) nicotinohydrazide (L), with an acylhydrazone group was synthesized and characterized. Subsequently, four porous Cd(ii)-MOFs, [Cd(L)(NO)] (1), [Cd(L)Cl] (2), [Cd(L)Br] (3), and [Cd(L)I] (4), were assembled using the ligand L by a solvothermal method and characterized by single-crystal X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, and powder X-ray diffraction. Structural analysis shows that the coordination environments around Cd(ii) in all the four compounds are different due to the different coordinated anions.

Three Ag, Cu and Cd coordination polymers based on the new asymmetrical ligand 2-{4-[(1H-imidazol-1-yl)methyl]phenyl}-5-(pyridin-4-yl)-1,3,4-oxadiazole: syntheses, characterization and emission properties.

The new asymmetrical organic ligand 2-{4-[(1H-imidazol-1-yl)methyl]phenyl}-5-(pyridin-4-yl)-1,3,4-oxadiazole (L, CHNO), containing pyridine and imidazole terminal groups, as well as potential oxdiazole coordination sites, was designed and synthesized. The coordination chemistry of L with soft Ag, Cu and Cd metal ions was investigated and three new coordination polymers (CPs), namely, catena-poly[[silver(I)-μ-2-{4-[(1H-imidazol-1-yl)methyl]phenyl}-5-(pyridin-4-yl)-1,3,4-oxadiazole] hexafluoridophosphate], {[Ag(L)]PF}, catena-poly[[copper(I)-di-μ-iodido-copper(I)-bis(μ-2-{4-[(1H-imidazol-1-yl)methyl]phenyl}-5-(pyridin-4-yl)-1,3,4-oxadiazole)] 1,4-dioxane monosolvate], {[CuI(L)]·CHO}, and catena-poly[[[dinitratocopper(II)]-bis(μ-2-{4-[(1H-imidazol-1-yl)methyl]phenyl}-5-(pyridin-4-yl)-1,3,4-oxadiazole)]-methanol-water (1/1/0.65)], {[Cd(L)(NO)]·2CHO·0.

[Ag-Ag] Unit-Encapsulated Trimetallic Cages: One-Pot Syntheses and Modulation of Argentophilic Interactions by the Uncoordinated Substituents.

Four [Ag-Ag] unit-encapsulated trimetallic cages 1-4 were synthesized from one new tripodal ligand L and silver salts in different solvent systems by a one-pot method. The formation of coordination cages occurred simultaneously with the condensation of amino groups and ketone. The remarkable structural feature of cages 1-4 is their spontaneous incorporation of [Ag-Ag] cationic units.

Visual Recognition and Removal of CH from CH/CH Mixtures by a Cu-MOF.

A Cu-MOF was found to be a highly selective visual sensor for recognizing CH. Gas chromatography studies indicated that it can be used to effectively remove minor amounts of CH from CH/CH mixtures (98:2) and produce highly pure CH (nearly 100%).

Characterization and gas adsorption of a novel three-dimensional metal-organic framework (MOF) generated from a new polydentate fluorene-bridged ligand.

A polydentate ligand bridged by a fluorene group, namely 9,9-bis(2-hydroxyethyl)-2,7-bis(pyridin-4-yl)fluorene (L), has been prepared under solvothermal conditions in acetonitrile. Crystals of the three-dimensional metal-organic framework (MOF) poly[[[μ-9,9-bis(2-hydroxyethyl)-2,7-bis(pyridin-4-yl)fluorene-κN:N':O]bis(methanol-κO)(μ-sulfato-κO:O')nickel(II)] methanol disolvate], {[Ni(SO)(CHNO)(CHOH)]·2CHOH}, (I), were obtained by the solvothermal reaction of L and NiSO in methanol. The ligand L forms a two-dimensional network in the crystallographic bc plane via two groups of O-H.

Unique Eu(II) Coordination Environments with a Janus Cryptand.

Two new Eu(II)-containing cryptates were prepared with a new nitrogenous cryptand functionalized with three benzo groups. The introduction of three aromatic rings into the ligand backbone imparts lopsided geometrical features on the resulting Eu(II) coordination environments. In both complexes, the interactions between Eu and the amines on the aromatic side of the molecule are weaker than those on the nonaromatic side, resulting in one discrete unit with two distinct faces.

[Dy(acac)₃(dppn)]·C₂H₅OH: construction of a single-ion magnet based on the square-antiprism dysprosium(III) ion.

The present work reports a new mononuclear Dy(III) complex [Dy(acac)3(dppn)]·C2H5OH (1) (acac = acetylacetone, dppn = benzo[i]dipyrido-[3, 2-a:2',3'-c]phenazine). X-ray crystallography analysis reveals that compound 1 is a discrete molecular complex and the Dy(III) center lies in a square-antiprism coordination environment. Furthermore, complex 1 shows single-ion magnet (SIM) behavior.

[Ag(2)(C(33)H(26)N(2)O(2))(H(2)O)(2)(SO(3)CF(3))(2)].0.5C(6)H(6): a luminescent supramolecular silver(I) complex based on metal-carbon and metal-heteroatom interactions.

A novel fulvene-type bidentate ligand 1 has been synthesized by an aroylation reaction of cyclohexyl-substituted cyclopentadienyl anions. Compound 1 crystallizes in the triclinic space group P(-)1, with a = 7.0419(5) A, b = 11.