Recent progress on porous MOFs for process-efficient hydrocarbon separation, luminescent sensing, and information encryption

Unveiling the Molecular Origin of Vapor-Liquid Phase Transition of Bulk and Confined Fluids

At temperatures below the critical temperature, discontinuities in the isotherms are one critical issue in the design and construction of separation units, affecting the level of confidence for a prediction of vapor–liquid equilibriums and phase transitions. In this work, we study the molecular mechanisms of fluids that involve the vapor–liquid phase transition in bulk and confinement, utilizing grand canonical (GCE) and meso-canonical (MCE) ensembles of the Monte Carlo simulation. Different geometries of the mesopores, including slit, cylindrical, and spherical, were studied. During phase transitions, condensation/evaporation hysteretic isotherms can be detected by GCE simulation, whereas employing MCE simulation allows us to investigate van der Waals (vdW) loop with a vapor spinodal point, intermediate states, and a liquid spinodal point in the isotherms. Depending on the system, the size of the simulation box, and the MCE method, we are able to identify three distinct groups of vdW-type isotherms for the first time: (1) a smooth S-shaped loop, (2) a stepwise S-shaped loop, and (3) a stepwise S-shaped loop with just a vertical segment. The first isotherm type is noticed in the bulk and pores having small box sizes, in which vapor and liquid phases are close and not clearly identified. The second and the third types occurred in the bulk, cylindrical, and slit mesopores with sufficiently large spaces, where vapor and liquid phases are distinctly separated. Results from our studies provide an insight analysis into vapor–liquid phase transitions, elucidating the effect of the confinement of fluid behaviors in a visual manner.

Exchange of coordinated carboxylates with azolates as a route to obtain a microporous zinc-azolate framework

Metal-organic frameworks (MOFs) containing open metal sites are advantageous for wide applications. Here, carboxylate linkers are replaced with triazolate coordination in pre-formed Zn-MOF-74 via solvent-assisted linker exchange (SALE) to prepare the novel NU-250, within the known hexagonal channel-based MAF-X25 series that has not previously been synthesized de novo.

Water-Stable Eu6-Cluster-Based fcu-MOF with Exposed Vinyl Groups for Ratiometric and Fluorescent Visual Sensing of Hydrogen Sulfide

Detection of H₂S in the biological system has attracted enormous attention in recent years. In this work, a new vinyl-functionalized metal-organic framework (MOF), [(Me₂NH₂)₂] [Eu₆(μ₃-OH)₈(BDC-CH═CH₂)₆(H₂O)₆] (Eu-BDC-CH═CH₂, BDC-CH═CH₂ = 2-vinylterephthalic acid), was synthesized under solvothermal conditions. The vinyl groups in the ligands can not only modulate the "antenna effect" of the ligand on Eu³⁺ ions but also serve as an exposed reactive site to allow for the quantitative detection of H₂S by Eu-BDC-CH═CH₂. The ratiometric fluorescent probe has the advantages of water stability, acid-base stability (pH = 2-11), fast response (<2 min), high selectivity, and sensitivity (LOD = 38.4 μM). We also used Eu-BDC-CH═CH₂ to detect and analyze H₂S in tap and lake waters, demonstrating the potential of the probe for biological and environmental applications. In addition, the MOF-based agarose hydrogel film allows for the visual detection of H₂S via a smartphone by identifying the RGB values. The vinyl-functionalized MOF can thus be a powerful sensing platform for H₂S.

Porous Metal-Organic Frameworks for Hydrogen Storage

The high gravimetric energy density and environmental benefit place hydrogen as a promising alternative to the widely used fossil fuel, which is however impeded by the lack of safe, energy-saving...

Folic acid modified UiO-66 nano drug carrier for combination therapy

The drug delivery system which called RB-Drug@UiO-66-FA can release anticancer drugs slowly in an acidic environment, and generate 1O2 under light exposure, achieving the effect of chemotherapy–photodynamic therapy.

Preparation of nanoscale cationic metal–organic framework Nano Mn(iii)-TP for theranostics based on valence changes

Schematic illustrations of the synthesis and working principle of a platform MTXNa@Nano Mn(iii)-TP for tumor theranostics.