8 research outputs found
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
N<sub>2</sub>, H<sub>2</sub>, and CO<sub>2</sub> gases and relatively
strong interactions between CO<sub>2</sub> 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 cadmiumÂ(II) coordination
polymer with (2-carboxyethyl)Â(phenyl)Âphosphinate (L<sup>2–</sup>) and 4,4′-bipyridine (bipy) as ligands, namely, [CdÂ(L)Â(bipy)Â(H<sub>2</sub>O)<sub>2</sub>] (<b>1</b>), can be converted to two
new two-dimensional/three-dimensional varieties under hydrothermal
treatments at different temperatures, that is, [CdÂ(L)Â(bipy)] (<b>2</b>) and [CdÂ(L)Â(bipy)<sub>0.5</sub>]·0.5H<sub>2</sub>O
(<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 (KH<sub>2</sub>PO<sub>4</sub>)
Temperature-Dependent Crystal Self-Assembly, Disassembly, and Reassembly Among Three Cadmium(II) Carboxylate-Phosphinates
A metastable three-dimensional cadmiumÂ(II) coordination
polymer with (2-carboxyethyl)Â(phenyl)Âphosphinate (L<sup>2–</sup>) and 4,4′-bipyridine (bipy) as ligands, namely, [CdÂ(L)Â(bipy)Â(H<sub>2</sub>O)<sub>2</sub>] (<b>1</b>), can be converted to two
new two-dimensional/three-dimensional varieties under hydrothermal
treatments at different temperatures, that is, [CdÂ(L)Â(bipy)] (<b>2</b>) and [CdÂ(L)Â(bipy)<sub>0.5</sub>]·0.5H<sub>2</sub>O
(<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 (KH<sub>2</sub>PO<sub>4</sub>)
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]Â[LnÂ(NDC)<sub>2</sub>(H<sub>2</sub>O)]·H<sub>2</sub>O [Ln
= La (<b>1</b>), Pr (<b>2</b>)], [HBBI]<sub>2</sub>[SmÂ(NDC)<sub>2</sub>(H<sub>2</sub>O)]<sub>2</sub>·1/2H<sub>2</sub>O (<b>3</b>), and [HBBI]Â[LnÂ(NDC)<sub>2</sub>(H<sub>2</sub>O)] [Ln =
Eu (<b>4</b>), Gd (<b>5</b>), Tb (<b>6</b>), Dy
(<b>7</b>), Er (<b>8</b>)] [Ln = lanthanide, H<sub>2</sub>NDC = 1,4-naphthalenedicarboxylic acid, BBI = bisÂ(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>2<sub>1</sub>/<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<sup>2–</sup> 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<sup>III</sup> 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]Â[LnÂ(NDC)<sub>2</sub>(H<sub>2</sub>O)]·H<sub>2</sub>O [Ln
= La (<b>1</b>), Pr (<b>2</b>)], [HBBI]<sub>2</sub>[SmÂ(NDC)<sub>2</sub>(H<sub>2</sub>O)]<sub>2</sub>·1/2H<sub>2</sub>O (<b>3</b>), and [HBBI]Â[LnÂ(NDC)<sub>2</sub>(H<sub>2</sub>O)] [Ln =
Eu (<b>4</b>), Gd (<b>5</b>), Tb (<b>6</b>), Dy
(<b>7</b>), Er (<b>8</b>)] [Ln = lanthanide, H<sub>2</sub>NDC = 1,4-naphthalenedicarboxylic acid, BBI = bisÂ(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>2<sub>1</sub>/<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<sup>2–</sup> 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<sup>III</sup> 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 [Ln<sub>2</sub>(1-tza)<sub>4</sub>(NO<sub>3</sub>)<sub>2</sub>(2,2′-bipy)<sub>2</sub>] (Ln = Sm (<b>1</b>), Eu (<b>2</b>), Gd (<b>3</b>), Tb (<b>4</b>), Dy (<b>5</b>)), [Dy<sub>2</sub>(1-tza)<sub>4</sub>Cl<sub>2</sub>(2,2′-bipy)<sub>2</sub>] (<b>6</b>), and [Yb<sub>2</sub>(1-tza)<sub>4</sub>(NO<sub>3</sub>)<sub>2</sub>(2,2′-bipy)<sub>2</sub>] (<b>7</b>) (1-tza = tetrazole-1-acetate
and 2,2′-bipy = 2,2′-bipyridine). They are dinuclear
complexes possessing similar structures but different lanthanideÂ(III)
ion coordination geometries because of the distinction of peripheral
anions (such as NO<sub>3</sub><sup>–</sup> and Cl<sup>–</sup>) and the effect of lanthanide contraction. The variable-temperature
magnetic susceptibilities of <b>1</b>–<b>6</b> were
measured. Both Dy<sup>III</sup> complexes (<b>5</b> and <b>6</b>) display field-induced single-molecule magnet behaviors.
Ab initio calculations revealed that the Dy<sup>III</sup> complex <b>6</b> possesses a more anisotropic Dy<sup>III</sup> ion in comparison
to that in <b>5</b>. The room-temperature photoluminescence
spectra of Sm<sup>III</sup> (<b>1</b>), Eu<sup>III</sup> (<b>2</b>), Tb<sup>III</sup> (<b>4</b>), and Dy<sup>III</sup> (<b>5</b> and <b>6</b>) complexes exhibit strong characteristic
emissions in the visible region, whereas the Yb<sup>III</sup> (<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, (Et<sub>4</sub>N)Â(CrO<sub>3</sub>X) (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, (Et<sub>4</sub>N)Â(CrO<sub>3</sub>X) (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