Polyamine-Cladded 18-Ring-Channel Gallium Phosphites with High-Capacity Hydrogen Adsorption and Carbon Dioxide Capture

In this study, we synthesized a unique inorganic framework bearing the largest 18-membered-ring channels in gallium phosphites, denoted as NTHU-15, which displayed genuine porosity even though large organic templates were present. The idea of using the “template-cladded” strategy succeeded in releasing channel space of up to ∼24% of the unit-cell volume as highly positive-charged organic templates were manipulated to cling to the anionic inorganic walls. NTHU-15 showed both high H₂ uptake of 3.8 mmol/g at 77 K and effective CO₂ adsorption of ∼2.4 mmol/g at 298 K, which surpassed those of all other known extra-large-channel inorganic framework structures. NTHU-15 has been successful at overcoming the long-standing problem of organic-templated extra-large-channel structures as opposed to a “true open” framework. Moreover, it realized practical gas sorption functionality in innovated metal phosphites. In view of its high stability in hot water and high selectivity for CO₂ adsorption, NTHU-15 may be the first novel inorganic framework material to be applied to the field of flue gas cleaning

Cordierite@MOFs with Easy Recovery in CO₂ Cycloaddition

The objective of this research is to create monolithic heterogeneous catalysts (cordierite@MOFs) through the application of metal–organic framework (MOF) materials onto honeycomb cordierite for CO2 cycloaddition. By employing monolithic catalysts instead of powdered catalysts, the recycling and reusability of catalysts during postreaction treatment can be significantly improved

One-pot synthesis of Claisen–Schmidt reaction through (<i>E</i>)-chalcone derivatives: Spectral studies in human serum albumin protein binding and molecular docking investigation

<p>An efficient and environmentally benign one-pot multicomponent synthesis of <i>E</i>-chalcones was developed using a mild and reusable new boron nitride-sulphonic acid catalyst. The catalyst was prepared by activating the boron nitride surface with nitric acid, followed by a simple reaction with 3-mercaptopropyl trimethoxysilane. The catalyst was characterized and morphological properties were studied by Fourier transform infrared, X-ray diffraction, transmission electron spectroscopy, scanning electron microscopy, Brunauer–Emmett–Teller theory, and Raman spectroscopy techniques. The solid acid catalyst was recycled five times in a Claisen–Schmidt reaction to synthesize new chalcone derivatives, and X-ray crystallography was used to elucidate the structure of (<i>E</i>)-1-(anthracen-9-yl)-3-(2-(4-methylpiperazin-1-yl)quinolin-3-yl)prop-2-en-1-one. A fluorescence quench titration method was used to assess its binding ability with human serum albumin (HSA), while molecular docking was also performed to get a more detailed insight into their interaction at the binding site of HSA.</p

Metal–Organic Framework–Polymer Composite as a Highly Efficient Sorbent for Sulfonamide Adsorption and Desorption: Effect of Coordinatively Unsaturated Metal Site and Topology

In this study, we first demonstrated the effect of two types of metal–organic framework–polymer (MOF–polymer) monoliths on in-tube solid-phase microextraction (IT-SPME) of sulfonamides. Sulfonamides were successfully adsorbed onto MIL-101­(Cr)–polymer but were difficult to elute due to these sulfonamides could interact via Lewis acid–base interaction with the presence of Cr­(III) coordinatively unsaturated metal sites (CUS). Moreover, the cage-type topology of MIL-101­(Cr) that could produce multiple pathways thus complicates the desorption of the test analytes from the sorbent. Contrastingly, MIL-53­(Al)–polymer provided weaker Al­(III) CUS, and its one-dimensional channel pore structure could provide an unhindered pathway for sulfonamides transfer during elution. After optimizing the IT-SPME condition such as MOF content, pH of sample matrix, column length, extraction flow rate, and elution volume, the calculated extraction recovery of sulfonamides in MIL-53­(Al)–polymer as analyzed by microemulsion electrokinetic chromatography (MEEKC) were in the range of 40%–90% with relative standard deviations (RSDs) below 5% and a reusability of at least 30 times

Object-oriented synthetic approach toward angular and linear fused pyrazoloquinolines of biological importance with InCl₃ catalyst

<p>A simple and short approach for the synthesis of pyrazolo[3,4-b]quinoline (<b>3a</b>–<b>3p</b>) and pyrazolo[4,3-c]quinoline (<b>6a</b>–<b>6 h</b>) using various Lewis acid catalysts was developed. InCl₃ was found to be more effective in providing greater yield of products compared to Yb(OTf)₃, Sc(OTf)₃, SnCl₄, AlCl₃, TiCl₄, ZnCl₂, FeCl₃, and BF₃ · Et₂O. Moreover, a comparison of conventional and microwave methods has revealed that the latter method is more efficient compared to former one. Structures were confirmed by Fourier transform infrared, mass spectrometry, ¹H and ¹³C NMR, X-ray crystallography, and elemental analyses. All of the synthesized compounds were evaluated for α-glucosidase inhibitory activity. Compounds <b>3a, 3p, 3i, 3 h, 3k, 3o,</b> and <b>3 g</b> exhibited anti α-glucosidase inhibitory activity with IC₅₀ values of 57.5, 60.3, 65.9, 71.9, 80.8, 123.7, and 126.4 µM, respectively, which is quite comparable to the standard drug acarbose (IC₅₀ = 115.8 µM).</p

Raman Observation of the “Volcano Curve” in the Formation of Carbonized Metal–Organic Frameworks

The carbonization of various types of metal–organic frameworks (MOFs) was carried out under N₂ gas flow and high temperature. The formation of carbonized MOFs (CMOFs) was monitored by Raman spectroscopy. In addition to the well-known D and G bands in Raman spectra, the salient G′ band feature was observed only in Mn-, Fe-, Co-, and Ni-containing CMOFs. On the other hand, CMOFs containing other metals (Al, Cr, V, Cu, and Zr) do not show the G′ band. Furthermore, the G′ band was also observed when we mixed the nitrate salts of Mn­(II), Fe­(III), and Co­(II) with Al-containing MOFs using the same treatment conditions as in the formation of CMOFs. The G′ band is known to be related to the stacking order of graphitic layers. The presence of the Raman G′ band in CMOFs can be ascribed to the catalytic activity of Mn, Fe, Co, and Ni. The trend of the G′ band to G band intensity ratio resembles the “volcano curve” in the description of the behavior of catalytic activities of transition metals. The G′ bands in Mn-, Fe-, Co-, and Ni-containing CMOFs were well-fitted with two-component peaks which indicates that these CMOFs have well-stacked graphitic structures

Multidimensional (0D to 3D) Alkaline-Earth Metal Diphosphonates: Synthesis, Structural Diversity, and Luminescence Properties

A series of new alkaline-earth metal diphosphonate frameworks were successfully synthesized under solvothermal reaction condition (160 °C, 3 d) using 1-hydroxyethylidene-1,1-diphosphonic acid (CH₃C­(OH)­(H₂PO₃)₂, hedpH₄) as a diphosphonate building block and Mg­(II), Ca­(II), Sr­(II), or Ba­(II) ions as alkaline-earth metal ion centers in water, dimethylformamide, and/or EtOH media. These diphosphonate frameworks, (H₂NMe₂)₄­[Mg­(hedpH₂)₃]·3H₂O (<b>1</b>), (H₂NMe₂)₂­[Ca­(hedpH₂)₂] (<b>2</b>), (H₂NMe₂)₂­[Sr₃(hedpH₂)₄­(H₂O)₂] (<b>3</b>), and [Ba₃(hedpH₂)₃]·H₂O (<b>4</b>) exhibited interesting structural topologies (zero-, one-, two-, and three-dimensional (0D, 1D, 2D, and 3D, respectively)), which are mainly depending on the metal ions and the solvents used in the synthesis. The single-crystal analysis of these newly synthesized compounds revealed that <b>1</b> was a 0D molecule, <b>2</b> has 1D chains, <b>3</b> was a 3D molecule, and <b>4</b> has 2D layers. All compounds were further characterized using thermogravimetric analysis, solid-state ³¹P NMR, powder X-ray diffraction analysis, UV–vis spectra, and infrared spectroscopy. In addition, Eu­(III)- and Tb­(III)-doped compounds of <b>1</b>–<b>4</b>, namely, (H₂NMe₂)₄­[Ln_<i>x</i>Mg_1–<i>x</i>(hedpH₂)₂­(hedpH_2–<i>x</i>)]·3H₂O (<b>1Ln</b>), (H₂NMe₂)₂­[Ln_<i>x</i>Ca_1–<i>x</i>(hedpH₂)­(hedpH_2–<i>x</i>)] (<b>2Ln</b>), (H₂NMe₂)₂[Ln_<i>x</i>Sr_3–<i>x</i>(hedpH₂)₃(hedpH_2–<i>x</i>)­(H₂O)₂] (<b>3Ln</b>), and [Ln_<i>x</i>Ba_3–<i>x</i>(hedpH₂)₂­(hedpH_2–<i>x</i>)]·H₂O (<b>4Ln</b>) (where Ln = Eu, Tb), were synthesized, and their photoluminescence properties were studied. The quantum yield of <b>1Eu</b>–<b>4Eu</b> was measured with reference to commercial red phosphor, Y₂O₂S:Eu³⁺ (YE), and the quantum yield of terbium-doped compounds <b>1Tb</b>–<b>4Tb</b> was measured with reference to commercial green-emitting phosphor CeMgAl₁₀O₁₇:Tb³⁺. Interestingly, the compound <b>2Eu</b> showed very high quantum yield of 92.2%, which is better than that of the reference commercial red phosphor, YE (90.8%)

Thermal Stability of Metal–Organic Frameworks and Encapsulation of CuO Nanocrystals for Highly Active Catalysis

We report an aerosol-based approach to study the thermal stability of metal–organic frameworks (MOFs) for gas-phase synthesis of MOF-based hybrid nanostructures used for highly active catalysis. Temperature-programmed electrospray-differential mobility analysis (TP-ES-DMA) provides the characterization of temperature-dependent morphological change directly in the gas phase, and the results are shown to be highly correlated with the structural thermal stability of MOFs determined by the traditional measurements of porosity and crystallinity. The results show that MOFs underwent thermal decomposition via simultaneous disassembly and deaggregation. Trimeric Cr-based MIL-88B-NH₂ exhibited a higher temperature of decomposition (<i>T</i>_d), 350 °C, than trimeric Fe-based MIL-88B-NH₂, 250 °C. For UiO-66, a significant decrease of <i>T</i>_d by ≈100 °C was observed by using amine-functionalized ligands in the MOF structure. Copper oxide nanocrystals were successfully encapsulated in the UiO-66 crystal (Cu_<i>x</i>O@UiO-66) by using a gas-phase evaporation-induced self-assembly approach followed by a suitable thermal treatment below <i>T</i>_d (i.e., determined by TP-ES-DMA). Cu_<i>x</i>O@UiO-66 demonstrated a very high catalytic activity and stability to CO oxidation, showing at least a 3-time increase in CO conversion compared to the bare CuO nanoparticle samples. The study demonstrates a prototype methodology (1) to determine structural thermal stability of MOFs using a gas-phase electrophoretic method (TP-ES-DMA) and (2) to gas-phase synthesize CuO nanocrystals encapsulated in MOFs

Solvothermal Synthesis, Structural Diversity, and Properties of Alkali Metal–Organic Frameworks Based on V‑shaped Ligand

A series of four new metal–organic frameworks, [Na₂(SBA)] (<b>1</b> or <b>CYCU-6</b>), [K₈(H₂O)₂(SBA)₄(DMF)] (<b>2</b>), [Rb₂(SBA)] (<b>3</b>), and [Cs­(H₂O)­(HSBA)]·DMF (<b>4</b>), have been constructed under solvothermal conditions by using 4,4′-sulfonyldibenzoic acid (H₂SBA) as ligand. The structure of the complexes has been determined by single-crystal X-ray diffraction analysis and further characterized by elemental analyses, reflectance UV–vis, and IR spectra, powder X-ray diffraction (PXRD), and thermogravimetric analysis (TGA). The single crystal X-ray structural studies showed that all the complexes display three-dimensional (3D) structures containing inorganic motifs with one-dimensional chains connected through organic linkers and forming 3D networks. Among the four complexes, the Na­(I) complex (<b>1</b>) displays very high thermal stability, which was inferred from TGA and PXRD results. Moreover, the solid state luminescent properties of the new complexes have been investigated at room temperature. In addition, the gas sorption properties of <b>1</b> toward nitrogen, hydrogen, carbon dioxide, and methane are reported