Crystal Packing-Driven Selective Hg(II) Ion Sensing Using Thiazolothiazole-Based Water-Stable Zinc Metal-Organic Framework

Tetranuclear Cluster-Based Eu(III)-Metal-Organic Framework: Ratiometric Platform Design and Ultrasensitive Phenylglyoxylic Acid Detection

Phenylglyoxalic acid (PGA) is a typical metabolite produced by the invasion of styrene into the human body. The detection of PGA can not only reflect the health status of the human body but also assess the level of styrene contamination in the environment. Herein, a novel Eu(III)-MOF (Eu-ttpd) with excellent fluorescence properties was designed by employing the tetrazole-based ligand of 5-((4'-(tetrazol-5'-yl)benzyl)oxy) isophthalic acid (H2ttpd), which successfully used a fluorescent sensor for PGA. The as-synthesized Eu-ttpd features the unique 10-connected tetranuclear cluster [Eu4(μ3-O)2(COO)8]4+ and exhibits a novel (3,10)-connected topological. Benefiting from the perfectly matched excited-state energy levels of the employed H2ttpd ligand with PGA, rapid photoinduced electron transfer (PET) and Dexter-ET can occur, which entitle Eu-ttpd a fast fluorescence quenching response to PGA with a remarkable LOD of 0.269 μM. More importantly, by integrating Eu-ttpd and Mg,N-CDs into the polyacrylamide hydrogel, we optimized Eu-ttpd into a hydrogel sensor which exhibited enhanced detection ability (LOD = 0.052 μM) accompanied by a distinguished color transformation (red-to-blue) and realized ultrasensitive and visual detection of PGA. This work offers an indication for the development of smart sensing materials for human health and environmental safety.

Mechanistic insight into Pb2+ and Hg2+ ion sensing using cobalt-based coordination polymer in aqueous phase

Emissive inorganic-organic hybrid materials open up a new prospect of fast and efficient heavy metal ion sensing in an aqueous medium. Here, we demonstrate highly sensitive lead(II) ion detection attributed to excited-state host-guest interaction, where mercury(II) shows lesser quenching efficiency due to both ground- and excited-state interaction.

A "heat set" Zr-Diimide based Fibrous Metallogel: Multiresponsive Sensor, Column-based Dye Separation, and Iodine Sequestration

Sensing and monitoring hazardous contaminants in water and radioactive iodine sequestration is pivotal due to their detrimental impact on biological ecosystems. In this context, herein, a water stable zirconium-diimide based metallogel (Zr@MG) with fibrous columnar morphology is accomplished through the "heat set" method. The presence of diimide linkage with long aromatic chain manifests active luminescence properties in the linker as well as in the supramolecular framework structure. The as-synthesized Zr@MG xerogel can selectively detectCr₂O₇^2- (LOD = 0.52 ppm) and 2,4,6-trinitrophenol (TNP) (LOD = 80.2 ppb) in the aqueous medium. The Zr@MG paper strip-based detection for Cr₂O₇^2- and nitro explosive makes this metallogel reliable and an attractive luminescent sensor for practical use. Moreover, a column-based dye separation experiment was performed to show selective capture of positively charged methylene blue (MB) dye with 98 % separation efficiency from the mixture of two dyes. Also, the Zr@MG xerogel showed effective iodine sequestration from the vapor phase (232 wt%).

Water stable MOFs as emerging class of porous materials for potential environmental applications

Metal-organic frameworks (MOFs) are extensively recognized for their wide applications in a variety of fields such as water purification, adsorption, sensing, catalysis and drug delivery. The fundamental characteristics of the majority of MOFs, such as their structure and shape, are known to be sensitively impacted by water or moisture. As a result, a thorough evaluation of the stability of MOFs in respect to factors linked to these property changes is required. It is quite rare for MOFs in their early stages to have strong water-stability, which is necessary for the commercialization and development of wider applications of this interesting material. Also, numerous applications in presence of water have progressed considerably as a "proof of concept" stage in the past and a growing number of water-stable MOFs (WSMOFs) have been discovered in recent years. This review discusses the variables and processes that affect the aqueous stability of several MOFs, including imidazolate and carboxylate frameworks. Accordingly, this article will assist researchers in accurately evaluating how water affects the stability of MOFs so that effective techniques can be identified for the advancement of water-stable metal-organic frameworks (WSMOFs) and for their effective applications toward a variety of fields.

Three new Zn(ii) coordination polymers for highly selective and sensitive detection of Fe3+

In this work, three novel Zn(ii)-CPs with diverse structures and fascinating topologies can be highly selective and sensitive luminescent sensors for detection of Fe3+.

Facile synthesis of dual-ligand terbium-organic gels as ratiometric fluorescence probes for efficient mercury detection

Mercury (Hg) pollution can negatively impact ecosystems, and there is a need for simple Hg²⁺ monitoring platforms. Here, a dual-ligand fluorescence probe based on terbium-organic gels (Tb-L_0.2P_0.8 MOGs) was constructed for efficient Hg²⁺ detection. Tb-L_0.2P_0.8 MOGs were developed through a facile room-temperature gelation method, showing two emission peaks derived from luminol and Tb³⁺ at 424 nm and 544 nm, respectively. The aggregation-induced emission (AIE) effect between luminol and Tb³⁺ led to luminol with blue fluorescence. However, Hg²⁺ could dramatically quench the fluorescence signal of luminol at 424 nm because of the intense coordination interaction of Hg²⁺ with luminol and photo-induced electron transfer (PET). The Phen ligand could sensitize the luminescence of Tb³⁺ and offer a reference fluorescence, thus resulting in a unique ratiometric fluorescence response toward Hg²⁺. This novel nanoprobe had excellent linearity with Hg²⁺ concentrations range of 0.1-30 μM; the detection limit was 3.6 nM. The analysis of real samples showed the potential application of MOGs for measuring Hg²⁺ in porphyra and tap water. Mixed ligands were introduced for high-efficiency strategies to improve the analytical performance by regulating the emission behavior of MOGs.