Metallogels and Silver Nanoparticles Generated from a Series of Transition Metal-Based Coordination Polymers Derived from a New Bis-pyridyl-bis-amide Ligand and Various Carboxylates

A new series of coordination polymers, namely, <b>CP2</b> [{(H₂O)­Co_1.5(μ-3-bpna)_1.5(μ-btc)}·3DMF·3H₂O]_α, <b>CP3</b> [{Cd­(μ-3-bpna)­(μ-hbtc)}·CH₃OH·2H₂O]_α, <b>CP4</b> [{Co­(μ-3-bpna)­(μ-ipa)}·DMF·2H₂O]_α, <b>CP5</b> [{Co­(μ-3-bpna)­(μ-1,3-pda)}·DMF]_α, <b>CP6</b> [Cd­(μ-3-bpna)_0.5(μ-1,3-pda)]_α, <b>CP7</b> [(H₂O)­Co_0.5(μ-3-bpna)_0.5(μ-1,4-pda)_0.5]_α, and <b>CP8</b> [{Zn­(μ-3-bpna)­(μ-oba)}·DMF·2H₂O]_α, has been synthesized by reacting a hydrogen-bond-functionalized bis-pyridyl ligand, namely, <i>N</i>′,<i>N</i>″-di­(pyridin-3-yl)­naphthalene-2,6-dicarboxamide, with various transition metal salts and different di- or tricarboxylates (as co-ligand) displaying 2D and 3D network topology and having lattice-occluded solvents in the majority of cases. A 1D coordination polymer, namely, <b>CP1</b> [{Ag_0.5(μ-3-bpna)}_0.5·0.5BF₄·CH₃CN]_α, has also been isolated by reacting 3-<b>bpna</b> with AgBF₄ in the absence of any carboxylate co-ligand. All of the CPs were characterized by single crystal X-ray diffraction. Interestingly, two such CPs, namely, <b>CP1</b> and <b>CP2</b>, produced metallogels, which were characterized by rheology, transmission electron microscopy, and X-ray powder diffraction. The metallogel of <b>CP1</b> produced Ag nanoparticles within the gel bed upon exposure to light

New Series of Zn^II/Cd^II Mixed Ligand Coordination Polymers: Toward the Design of Metallogels

A new series of mixed ligand based coordination polymers (CPs) has been synthesized by reacting a new ligand, namely, hpdia (5-(4-hydroxyphenylazo)­isophthalic acid); various bispyridyl coligands (2,2′-bipyridine (2,2′-bpy), 4,4′-bipyridine (4,4′-bpy), and 1,2-di­(4-pyridyl)­ethylene (bpe)); and Zn­(NO₃)₂/Cd­(NO₃)₂ under solvothermal conditions. The molecular structure of hpdia was established by analyzing the single crystal X-ray diffraction (SXRD) data of the sodium salt of hpdia which turned out to be an alkali coordination polymer with a formula [(H₂O)₄Na₂(μ-hpdia)₄]_∞ (CP1). SXRD analyses of the other transition metal compounds, thus synthesized, revealed that they were all coordination polymers (except DCC3a discrete coordination complex) having formulas [{(H₂O)­Zn­(μ-hpdia)­(2,2′-bpy)}·H₂O]_∞ (CP2), [(H₂O)­Zn₂(μ-hpdia)₂(2,2′-bpy)₂]₂ (DCC3), [{(H₂O)­Cd­(μ-hpdia)­(2,2′-bpy)}·H₂O]_∞ (CP4), [{(H₂O)­Zn­(μ-hpdia)­(4,4′-bpy)}·H₂O]_∞ (CP5), [Zn_0.5(hpdia)­(μ-4,4′-bpy)_0.5]_∞ (CP6), [{(H₂O)₂Cd₂(μ-hpdia)₂(μ-4,4′-bpy)}·2H₂O]_∞ (CP7), and [{Zn₂(μ-hpdia)₂(μ-bpe)}·H₂O]_∞ (CP8). The majority of the CPs were lattice occluded molecular solids. Remarkably, the reactants of all of the coordination polymers and also DCC3 showed the ability to produce metallogels which were characterized by rheology and scanning electron microscopy (SEM). The results supported the structural consideration based on which these metallogelators were designed

Metallogels and Silver Nanoparticles Generated from a Series of Transition Metal-Based Coordination Polymers Derived from a New Bis-pyridyl-bis-amide Ligand and Various Carboxylates

A new series of coordination polymers, namely, <b>CP2</b> [{(H₂O)­Co_1.5(μ-3-bpna)_1.5(μ-btc)}·3DMF·3H₂O]_α, <b>CP3</b> [{Cd­(μ-3-bpna)­(μ-hbtc)}·CH₃OH·2H₂O]_α, <b>CP4</b> [{Co­(μ-3-bpna)­(μ-ipa)}·DMF·2H₂O]_α, <b>CP5</b> [{Co­(μ-3-bpna)­(μ-1,3-pda)}·DMF]_α, <b>CP6</b> [Cd­(μ-3-bpna)_0.5(μ-1,3-pda)]_α, <b>CP7</b> [(H₂O)­Co_0.5(μ-3-bpna)_0.5(μ-1,4-pda)_0.5]_α, and <b>CP8</b> [{Zn­(μ-3-bpna)­(μ-oba)}·DMF·2H₂O]_α, has been synthesized by reacting a hydrogen-bond-functionalized bis-pyridyl ligand, namely, <i>N</i>′,<i>N</i>″-di­(pyridin-3-yl)­naphthalene-2,6-dicarboxamide, with various transition metal salts and different di- or tricarboxylates (as co-ligand) displaying 2D and 3D network topology and having lattice-occluded solvents in the majority of cases. A 1D coordination polymer, namely, <b>CP1</b> [{Ag_0.5(μ-3-bpna)}_0.5·0.5BF₄·CH₃CN]_α, has also been isolated by reacting 3-<b>bpna</b> with AgBF₄ in the absence of any carboxylate co-ligand. All of the CPs were characterized by single crystal X-ray diffraction. Interestingly, two such CPs, namely, <b>CP1</b> and <b>CP2</b>, produced metallogels, which were characterized by rheology, transmission electron microscopy, and X-ray powder diffraction. The metallogel of <b>CP1</b> produced Ag nanoparticles within the gel bed upon exposure to light

Healthnet News v.16:no.4 Winter 2001

A newsletter for public librarians and others interested in consumer health information services

Perpetually Self-Propelling Chiral Single Crystals

When heated, single crystals of enantiomerically pure d- and l-pyroglutamic acid (PGA) are capable of recurring self-actuation due to rapid release of latent strain during a structural phase transition, while the racemate is mechanically inactive. Contrary to other thermosalient materials, where the effect is accompanied by crystal explosion due to ejection of debris or splintering, the chiral PGA crystals respond to internal strain with unprecedented robustness and can be actuated repeatedly without deterioration. It is demonstrated that this superelasticity is attained due to the low-dimensional hydrogen-bonding network which effectively accrues internal strain to elicit propulsion solely by elastic deformation without disintegration. One of the two polymorphs (β) associated with the thermosalient phase transition undergoes biaxial <i>negative</i> thermal expansion (α_<i>a</i> = −54.8(8) × 10^–6 K^–1, α_<i>c</i> = −3.62(8) × 10^–6 K^–1) and exceptionally large uniaxial thermal expansion (α_<i>b</i> = 303(1) × 10^–6 K^–1). This second example of a thermosalient solid with anomalous expansion indicates that the thermosalient effect can be expected for first-order phase transitions in soft crystals devoid of an extended 3D hydrogen-bonding network that undergo strongly anisotropic thermal expansion around the phase transition

A Functional Zn(II) Metallacycle Formed from an N‑Heterocyclic Carbene Precursor: A Molecular Sensor for Selective Recognition of Fe³⁺ and IO₄^– Ions

We have reported the synthesis and structural characterization of a unique Zn­(II) metallacycle (<b>1</b>) and its utilization as a fluorescent probe for the shape-specific selective recognition (turn-off) of Fe³⁺ and IO₄^– ions. The relevant Stern–Volmer graphs indicate that the recognitions of Fe³⁺ and IO₄^– ions are examples of diphasic and monophasic quenchings, respectively. The title metallacycle has been prepared by the reaction of a novel N-heterocyclic carbene precursor, 1,3-bis­(2,6-diisopropyl-4-(pyridin-4-yl)­phenyl)-1<i>H</i>-imidazol-3-ium chloride/bromide (<b>L</b>), and zinc­(II) chloride salt. Notably, the ligand itself did not show any type of recognition for any ions. DFT calculations were performed on <b>L</b> and metallacycle <b>1</b> using the geometric parameters, obtained from their single-crystal X-ray diffraction data, to understand the electronic structures of the ligand and macrocycle. The detection limit for the recognition of the Fe³⁺ ion was determined to be 2.5 × 10^–6 mol/L, and that for IO₄^– ion was found to be 6.3 × 10^–5 mol/L

Single-Crystal-to-Single-Crystal Transformation of a Novel 2‑Fold Interpenetrated Cadmium-Organic Framework with Trimesate and 1,2-Bis(4-pyridyl)ethane into the Thermally Desolvated Form Which Exhibits Liquid and Gas Sorption Properties

A novel 2-fold interpenetrated, pillared, cadmium metal–organic framework, namely, [Cd­(HBTC)­BPE]_<i>n</i>·<i>n</i>DMF, has been synthesized using 1,3,5-benzenetricarboxylic acid and 1,2-bis­(4-pyridyl)­ethane (BPE). This compound has been desolvated and subjected to various liquids and gases for sorption studies. Structures of the as-synthesized (<b>1</b>), desolvated (<b>2</b>), and resolvated in benzene (<b>3</b>) have been determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis, IR spectra, and thermogravimetric/differential scanning calorimetry analysis. Single crystal X-ray analysis revealed a 2-fold interpenetrated, three-dimensional (3D) framework which exhibits a 3,5-connected network with the Schläfli symbol of [(6³)­(6⁹.8) and <i>hms</i> topology. Compound <b>1</b> exhibits a temperature-induced single-crystal-to-single-crystal (SC–SC) transformation upon the release of <i>N</i>,<i>N</i>′-dimethylformamide molecules forming compound <b>2</b> (stable up to 300 °C). SC–SC transformation is also observed when it is immersed in benzene, chloroform, 1,4-dioxane, and tetrahydrofuran. The uptake of different solvent molecules was analyzed, and desolvated samples selectively adsorb benzene, chloroform, 1,4-dioxane, and THF molecules over other selected polar solvents. Gas (N₂, CO₂, and N₂O) sorption experiments were also performed and the structure showed 2.5% N₂, 4.5% CO₂, and 3.4% N₂O absorption by mass at room temperature and moderate gas pressures (∼10 bar)

Single-Crystal-to-Single-Crystal Transformation of a Novel 2‑Fold Interpenetrated Cadmium-Organic Framework with Trimesate and 1,2-Bis(4-pyridyl)ethane into the Thermally Desolvated Form Which Exhibits Liquid and Gas Sorption Properties

A novel 2-fold interpenetrated, pillared, cadmium metal–organic framework, namely, [Cd­(HBTC)­BPE]_<i>n</i>·<i>n</i>DMF, has been synthesized using 1,3,5-benzenetricarboxylic acid and 1,2-bis­(4-pyridyl)­ethane (BPE). This compound has been desolvated and subjected to various liquids and gases for sorption studies. Structures of the as-synthesized (<b>1</b>), desolvated (<b>2</b>), and resolvated in benzene (<b>3</b>) have been determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis, IR spectra, and thermogravimetric/differential scanning calorimetry analysis. Single crystal X-ray analysis revealed a 2-fold interpenetrated, three-dimensional (3D) framework which exhibits a 3,5-connected network with the Schläfli symbol of [(6³)­(6⁹.8) and <i>hms</i> topology. Compound <b>1</b> exhibits a temperature-induced single-crystal-to-single-crystal (SC–SC) transformation upon the release of <i>N</i>,<i>N</i>′-dimethylformamide molecules forming compound <b>2</b> (stable up to 300 °C). SC–SC transformation is also observed when it is immersed in benzene, chloroform, 1,4-dioxane, and tetrahydrofuran. The uptake of different solvent molecules was analyzed, and desolvated samples selectively adsorb benzene, chloroform, 1,4-dioxane, and THF molecules over other selected polar solvents. Gas (N₂, CO₂, and N₂O) sorption experiments were also performed and the structure showed 2.5% N₂, 4.5% CO₂, and 3.4% N₂O absorption by mass at room temperature and moderate gas pressures (∼10 bar)

Table_1_Retinal changes in patients with idiopathic inflammatory myopathies: A case-control study in the MyoCite cohort.docx

BackgroundRetinal changes are the window to systemic vasculature. Therefore, we explored retinal changes in patients with Idiopathic inflammatory myopathies (IIM) as a surrogate for vascular health.MethodsAdult and Juvenile IIM patients (2017 ACR/EULAR criteria), visiting a tertiary care center in 2021 were enrolled for detailed ophthalmic examination in comparison with healthy controls (HC). Patients with conditions that precluded thorough posterior chamber examination were excluded. Scale variables are expressed as median (IQR). Multivariate analysis (binary logistic regression-BLR) was conducted, adjusting for age, gender, and comorbidities besides factors significant in univariate analysis.Results43 patients with IIM [31 females; age 36 (23–45) years; disease duration 5.5 (2-12) months] were enrolled for participation. DM (44%) was the most common diagnosis. IIM patients exhibited frequent attenuation of retinal vessels (32.6 vs. 4.3%, p ConclusionRetinal microvasculopathy and diminution of vision occur in nearly one-thirds to half of the patients with IIM. Microvasculopathy occurs across subtypes of IIM, and more so in adults, calling for further investigation as a surrogate for damage assessment and potentially even systemic vascular health.</p