Thiol and thioether-based metal-organic frameworks: synthesis, structure, and multifaceted applications.

Metal-organic frameworks (MOFs) are unique hybrid porous materials formed by combining metal ions or clusters with organic ligands. Thiol and thioether-based MOFs belong to a specific category of MOFs where one or many thiols or thioether groups are present in organic linkers. Depending on the linkers, thiol-thioether MOFs can be divided into three categories: (i) MOFs where both thiol or thioether groups are part of the carboxylic acid ligands, (ii) MOFs where only thiol or thioether groups are present in the organic linker, and (iii) MOFs where both thiol or thioether groups are part of azolate-containing linkers. MOFs containing thiol-thioether-based acid ligands are synthesized through two primary approaches; one is by utilizing thiol and thioether-based carboxylic acid ligands where the bonding pattern of ligands with metal ions plays a vital role in MOF formation (HSAB principle). MOFs synthesized by this approach can be structurally differentiated into two categories: structures without common structural motifs and structures with common structural motifs (related to UiO-66, UiO-67, UiO-68, MIL-53, NU-1100, etc.). The second approach to synthesize thiol and thioether-based MOFs is indirect methods, where thiol or thioether functionality is introduced in MOFs by techniques like post-synthetic modifications (PSM), post-synthetic exchange (PSE) and by forming composite materials. Generally, MOFs containing only thiol-thioether-based ligands are synthesized by interfacial assisted synthesis, forming two-dimensional sheet frameworks, and show significantly high conductivity. A limited study has been done on MOFs containing thiol-thioether-based azolate ligands where both nitrogen- and sulfur-containing functionality are present in the MOF frameworks. These materials exhibit intriguing properties stemming from the interplay between metal centres, organic ligands, and sulfur functionality. As a result, they offer great potential for multifaceted applications, ranging from catalysis, sensing, and conductivity, to adsorption. This perspective is organised through an introduction, schematic representations, and tabular data of the reported thiol and thioether MOFs and concluded with future directions.

A coordination driven 'heat-set' Zr-gel: efficient fluorophore probe for selective detection of Fe3+ and nitrofuran-based antibiotics and smart approach for UV protection.

Nature creates definite architecture with fluorescence capabilities and superior visual adaptation in many organisms, e.g., cephalopods, which differentiates them from their surroundings in the context of colour and texture that allows them to use this in defence, communication, and reproduction. Inspired by nature, we have designed a coordination polymer gel (CPG)-based luminescent soft material where the photophysical properties of the material can be tuned using a low molecular weight gelator (LMWG) with chromophoric functionalities. Herein, a water-stable coordination polymer gel-based luminescent sensor was created using zirconium oxychloride octahydrate as a metal source and H3TATAB (4,4',4''-((1,3,5-triazine-2,4,6-triyl)tris(azanediyl))tribenzoic acid) as a LMWG. The tripodal carboxylic acid gelator H3TATAB with a triazine backbone induces rigidity in the coordination polymer gel network structure along with the unique photoluminescent properties. The xerogel material can selectively detect Fe3+ and nitrofuran-based antibiotics (i.e., NFT) in aqueous medium through luminescent 'turn-off' phenomena. This material is a potent sensor because of the ultrafast detection of the targeted analytes (Fe3+ and NFT), with consistent efficacy in quenching activity up to five consecutive cycles. More interestingly, colorimetric, portable handy paper strip, thin film-based smart detection approaches (under an ultraviolet (UV) source) were introduced to make this material a viable sensor probe in real-time applications. In addition, we developed a facile method to synthesize CPG-polymer composite material that can be utilized as a transparent thin film to protect against UV radiation (200-360 nm), with approximately 99% absorption efficacy.

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 detectCr2O72- (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 Cr2O72- 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%).

Jaundice and anaemia as presenting features of an incomplete autoimmune polyglandular syndrome type II.

The coexistence of adrenal failure with either autoimmune thyroid disease and/or type 1 diabetes is defined as autoimmune polyglandular syndrome (APS) type 2 or Schmidt's syndrome. Vitiligo, hypergonadotropic hypogonadism, chronic autoimmune hepatitis, alopecia, pernicious anaemia and seronegative arthritis may also be present. We present a case of 45-year-old Indian man with progressive jaundice and asthenia for 3 months. He was also found to have pallor, icterus, dry coarse skin and delayed relaxation of ankle jerk. Investigations showed pancytopaenia with megaloblastic changes due to pernicious anaemia, autoimmune hypothyroidism and autoimmune adrenalitis with evolving adrenal insufficiency. Upper gastrointestinal endoscopy guided biopsy showed evidence of gastric mucosal atrophy. Patient responded well to hydroxocobalamin and thyroxine replacement. Detailed workup to check for evolving APS II is prudent in a hypothyroid patient presenting with pallor and jaundice. It may alert physicians to possible adrenal crisis in the future, especially after starting levothyroxine replacement in these patients.