A Two-Fold Interpenetrating Porous Metal–Organic Framework with a Large Solvent-Accessible Volume: Gas Sorption and Luminescent Properties

A luminescent porous metal–organic framework based on π-electron-rich tricarboxylate has been solvothermally prepared and characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, elemental analyses, and single-crystal X-ray diffraction analysis. This compound is a 2-fold interpenetrating framework with a large solvent-accessible volume and exhibits gas sorption behaviors for N₂, H₂, and CO₂ gases and relatively strong interactions between CO₂ and the framework. Furthermore, it also shows interesting guest-responsive luminescent changes toward different solvent molecules

Temperature-Dependent Crystal Self-Assembly, Disassembly, and Reassembly Among Three Cadmium(II) Carboxylate-Phosphinates

A metastable three-dimensional cadmium­(II) coordination polymer with (2-carboxyethyl)­(phenyl)­phosphinate (L^2–) and 4,4′-bipyridine (bipy) as ligands, namely, [Cd­(L)­(bipy)­(H₂O)₂] (<b>1</b>), can be converted to two new two-dimensional/three-dimensional varieties under hydrothermal treatments at different temperatures, that is, [Cd­(L)­(bipy)] (<b>2</b>) and [Cd­(L)­(bipy)_0.5]·0.5H₂O (<b>3</b>). Their syntheses, crystal structures, structural transformations, and luminescent properties are presented. In addition, <b>1</b> shows a second harmonic generation response that is ∼0.3 times that of KDP (KH₂PO₄)

Temperature-Dependent Crystal Self-Assembly, Disassembly, and Reassembly Among Three Cadmium(II) Carboxylate-Phosphinates

A metastable three-dimensional cadmium­(II) coordination polymer with (2-carboxyethyl)­(phenyl)­phosphinate (L^2–) and 4,4′-bipyridine (bipy) as ligands, namely, [Cd­(L)­(bipy)­(H₂O)₂] (<b>1</b>), can be converted to two new two-dimensional/three-dimensional varieties under hydrothermal treatments at different temperatures, that is, [Cd­(L)­(bipy)] (<b>2</b>) and [Cd­(L)­(bipy)_0.5]·0.5H₂O (<b>3</b>). Their syntheses, crystal structures, structural transformations, and luminescent properties are presented. In addition, <b>1</b> shows a second harmonic generation response that is ∼0.3 times that of KDP (KH₂PO₄)

Three-Dimensional Extended Frameworks Constructed from Dinuclear Lanthanide(III) 1,4-Naphthalenedicarboxylate Units with Bis(2,2′-biimidazole) Templates: Syntheses, Structures, and Magnetic and Luminescent Properties

Eight unprecedented Ln-NDC coordination polymers with BBI as templates {[HBBI]­[Ln­(NDC)₂(H₂O)]·H₂O [Ln = La (<b>1</b>), Pr (<b>2</b>)], [HBBI]₂[Sm­(NDC)₂(H₂O)]₂·1/2H₂O (<b>3</b>), and [HBBI]­[Ln­(NDC)₂(H₂O)] [Ln = Eu (<b>4</b>), Gd (<b>5</b>), Tb (<b>6</b>), Dy (<b>7</b>), Er (<b>8</b>)] [Ln = lanthanide, H₂NDC = 1,4-naphthalenedicarboxylic acid, BBI = bis­(2,2′-biimidazole)]} have been hydrothermally synthesized and structurally characterized by elemental analyses, IR spectra, and single-crystal X-ray diffraction. Complexes <b>1</b>–<b>8</b> crystallize in the monoclinic space group <i>P</i>2₁/<i>c</i> and display similar (8,8)-connected 3-D frameworks with different dinuclear Ln secondary building units due to the effect of Ln contraction and diverse coordination modes of NDC^2– ligands. As the ionic radii of Ln ions decrease, the coordination numbers of Ln ions decrease from 10, to 9, to 8. The variable-temperature magnetic properties of <b>2</b>–<b>8</b> have been investigated. The strong fluorescent emissions of <b>4</b> demonstrate that ligand-to-Eu^III energy transfer is efficient. In addition, thermogravimetric analyses and optical diffuse reflectance spectra of these compounds are also described

Three-Dimensional Extended Frameworks Constructed from Dinuclear Lanthanide(III) 1,4-Naphthalenedicarboxylate Units with Bis(2,2′-biimidazole) Templates: Syntheses, Structures, and Magnetic and Luminescent Properties

Eight unprecedented Ln-NDC coordination polymers with BBI as templates {[HBBI]­[Ln­(NDC)₂(H₂O)]·H₂O [Ln = La (<b>1</b>), Pr (<b>2</b>)], [HBBI]₂[Sm­(NDC)₂(H₂O)]₂·1/2H₂O (<b>3</b>), and [HBBI]­[Ln­(NDC)₂(H₂O)] [Ln = Eu (<b>4</b>), Gd (<b>5</b>), Tb (<b>6</b>), Dy (<b>7</b>), Er (<b>8</b>)] [Ln = lanthanide, H₂NDC = 1,4-naphthalenedicarboxylic acid, BBI = bis­(2,2′-biimidazole)]} have been hydrothermally synthesized and structurally characterized by elemental analyses, IR spectra, and single-crystal X-ray diffraction. Complexes <b>1</b>–<b>8</b> crystallize in the monoclinic space group <i>P</i>2₁/<i>c</i> and display similar (8,8)-connected 3-D frameworks with different dinuclear Ln secondary building units due to the effect of Ln contraction and diverse coordination modes of NDC^2– ligands. As the ionic radii of Ln ions decrease, the coordination numbers of Ln ions decrease from 10, to 9, to 8. The variable-temperature magnetic properties of <b>2</b>–<b>8</b> have been investigated. The strong fluorescent emissions of <b>4</b> demonstrate that ligand-to-Eu^III energy transfer is efficient. In addition, thermogravimetric analyses and optical diffuse reflectance spectra of these compounds are also described

Anion Effects on Lanthanide(III) Tetrazole-1-acetate Dinuclear Complexes Showing Slow Magnetic Relaxation and Photofluorescent Emission

Three types of lanthanide complexes based on the tetrazole-1-acetic acid ligand and the 2,2′-bipyridine coligand were prepared and characterized by single-crystal X-ray diffraction, IR spectroscopy, and elemental analyses; the formulas of these complexes are [Ln₂(1-tza)₄(NO₃)₂(2,2′-bipy)₂] (Ln = Sm (<b>1</b>), Eu (<b>2</b>), Gd (<b>3</b>), Tb (<b>4</b>), Dy (<b>5</b>)), [Dy₂(1-tza)₄Cl₂(2,2′-bipy)₂] (<b>6</b>), and [Yb₂(1-tza)₄(NO₃)₂(2,2′-bipy)₂] (<b>7</b>) (1-tza = tetrazole-1-acetate and 2,2′-bipy = 2,2′-bipyridine). They are dinuclear complexes possessing similar structures but different lanthanide­(III) ion coordination geometries because of the distinction of peripheral anions (such as NO₃^– and Cl^–) and the effect of lanthanide contraction. The variable-temperature magnetic susceptibilities of <b>1</b>–<b>6</b> were measured. Both Dy^III complexes (<b>5</b> and <b>6</b>) display field-induced single-molecule magnet behaviors. Ab initio calculations revealed that the Dy^III complex <b>6</b> possesses a more anisotropic Dy^III ion in comparison to that in <b>5</b>. The room-temperature photoluminescence spectra of Sm^III (<b>1</b>), Eu^III (<b>2</b>), Tb^III (<b>4</b>), and Dy^III (<b>5</b> and <b>6</b>) complexes exhibit strong characteristic emissions in the visible region, whereas the Yb^III (<b>7</b>) complex shows near-infrared (NIR) luminescence

Plastic Crystals with Polar Halochromate Anion: Thermosensitive Dielectrics Based upon Plastic Transition and Dipole Rotation

Plastic crystals functioning with rotatable components offer new opportunities in areas such as modern optoelectronic materials. Here, by taking advantage of controllable rotation of the polar component within the ion-pair plastic-crystal system, we present two such crystals, namely, (Et₄N)­(CrO₃X) (X = Cl or Br), which are unusual examples exhibiting two-staged thermosensitive dielectric responses above room temperature. The frequency-dependent response in the first stage is due to the structural phase transitions, whereas that in the second stage is induced by dynamic rotation of the polar halochromate anions in their NaCl-type plastic-crystal phases. The intrinsic mechanisms were also explicated by molecular dynamics simulations, providing a direct insight into the dynamic characteristics of these two compounds. These studies show that ionic plastic crystals functioning with polar groups are an attractive candidate as sensitive thermoresponsive dielectric materials

Plastic Crystals with Polar Halochromate Anion: Thermosensitive Dielectrics Based upon Plastic Transition and Dipole Rotation

Plastic crystals functioning with rotatable components offer new opportunities in areas such as modern optoelectronic materials. Here, by taking advantage of controllable rotation of the polar component within the ion-pair plastic-crystal system, we present two such crystals, namely, (Et₄N)­(CrO₃X) (X = Cl or Br), which are unusual examples exhibiting two-staged thermosensitive dielectric responses above room temperature. The frequency-dependent response in the first stage is due to the structural phase transitions, whereas that in the second stage is induced by dynamic rotation of the polar halochromate anions in their NaCl-type plastic-crystal phases. The intrinsic mechanisms were also explicated by molecular dynamics simulations, providing a direct insight into the dynamic characteristics of these two compounds. These studies show that ionic plastic crystals functioning with polar groups are an attractive candidate as sensitive thermoresponsive dielectric materials