Rana Dalapati

Carbon disulfide (CS2) has been widely recognized as a versatile building block in chalcogen chemistry and has attracted the research community to the synthesis of a variety of highly functionalized organic scaffolds. Conversely, carbon disulfide (CS₂) serves as a valuable chemical synthon due to its wide availability from various inexpensive sources and remarkable stability, making it a crucial substrate in organic chemistry. CS2 exhibits a versatile reactivity under mild ambient conditions for the synthesis of a library of S-containing biologically important molecules. The electrophilic nature of the carbon center, combined with the nucleophilicity of the sulfur atoms, enables CS2 to participate in a wide array of reactions, making it a key sulfur source for the introduction of sulfur functionalities into organic molecules. Moreover, the ambident nature of CS2 allows it to interact effectively with a range of nucleophiles, including amines, thiols, and organometallic reagents, leading to key intermediates such as dithiocarbamates and xanthates. This review summarizes recent developments in the use of carbon disulfide for the preparation of novel organosulfur compounds under mild reaction conditions. The sustainable techniques employed herein involve the use of non-toxic, low-cost, commercial-grade reagents and environmentally benign, greener solvents. By summarizing recent developments, this review aims to inspire further research in advancing the green synthesis of organosulfur compounds.

Dual-functional MOF enables efficient PFOA removal and sensitive detection via fluorescence turn-on through indicator displacement, offering a simple solution for PFAS remediation with real time monitoring.

Arsenic is a well-known, highly toxic carcinogen element that is widely found in nature, with numerous studies highlighting its hazardous impact on human health and the environment. Therefore, considering its toxicity and adverse health effects on mammals and the environment, rapid, sensitive, and effective methods for the recognition of arsenic are necessary. Over the past decade, a variety of fluorescent probes, such as small molecules, nanomaterials, gold nanoparticles (AuNPs), carbon dots (CDs), quantum dots (QDs), and more, have been designed and successfully employed for the recognition of lethal arsenic. Compared to other conventional sensor materials, sensors based on metal-organic frameworks (MOFs) are advantageous due to their simple preparation, easy functional group modulation, large specific surface area, and excellent chemical stability. In recent years, MOFs have been utilized as dual-functional materials for the detection and adsorptive removal of arsenic from water. This unique functionality distinguishes MOF-based materials from conventional sensors and arsenic adsorbents. Herein, we provide an overview of the state-of-the-art knowledge on the current development of MOFs for the fluorogenic detection of arsenic in aqueous media. Furthermore, the underlying detection mechanisms are also summarized in this review. The existing challenges in this field and potential remedial strategies for improving detection are elaborated upon in the relevant sections.

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This paper reports a wake-up gas sensor based on a lateral nanogap structure that is capable of increasing nanogap surface area by 11.2 times and thus improving the limit-of-detection (LOD) by 10 times down to 5 ppm in comparison to the previous vertical nanogap structure. Unlike the vertical nanogap structure with a suspended membrane, this lateral nanogap structure avoided fragile components and thus was able to reliably release a relatively large surface area of a 5-nm gap structure. The microfabricated lateral nanogap structure spanned over an enlarged area of 700 μm ² , in comparison to the maximum area of 62.5 μm2 in the previous vertical gap structure, with the highest surface-area-to-nanogap-size aspect ratio of 130 μm ² /nm. When coated with a customized linker, it demonstrated (1) a gas sensing capability down to 5 ppm under the exposure of hexanal at a flow rate of 50 sccm, (2) a high wake-up ON current of 460 nA, and (3) an ON/OFF ratio of 1.51, which are sufficient for detection.

Psychrotrophic bacteria, commonly called spoilage bacteria, can produce highly toxic hydrogen sulfide (H₂S) in meat products. Thus, monitoring the presence of hydrogen sulfide in meat samples is crucial for food safety and storage. Here, we report a unique chemical sensor based on supramolecular nanorods synthesized via copper ion induced self-assembly of N,N-bis[aspartic potassium salt]-3,4,9,10-perylenetetracarboxylic diimide (APBI-K). The self-assembled nanorods can specifically detect sulfide with a detection limit of 0.181 μM in solution. The nanorods suspended in pure water show a turn-on fluorescence sensing behavior along with color change, acting as a dual fluorometric and colorimetric sensor. Spectroscopic investigation confirms the sensing mechanism due to copper ion displacement induced by the association with sulfide. Based on the high selectivity and sensitivity, supramolecular nanorod sensors were successfully employed to detect H₂S in spoiled meat sample as well as dissolved H₂S in water.

An overview of recent development of optical chemosensors for detecting volatile aldehydes, covering the sensing mechanisms based on colorimetric, fluorometric, etc., or dual modes, in correlation with the materials design and structure optimization.

A well-known fluorophore molecule, pyrene was encapsulated into a stable metal organic framework by in situ encapsulation method. The existing metal-organic framework (MOF) called UiO-66 (UiO = University of Oslo) served as host material for pyrene fluorophore. The fluorescence of pyrene was quenched after encapsulation inside the porous host. Recovery of quenched fluorescence was accomplished by anion induced host dissolution, followed by the release of the fluorophore molecule. Using this anion induced dissolution, a selective sensing of fluoride anion in pure aqueous was achieved.

A hydrazine-functionalized, highly stable Al(III) based metal–organic framework (MOF) with CAU-10 (CAU = Christian-Albrechts-University) framework topology namely CAU-10-N₂H₃ (1) was specifically designed to detect lethal CN⁻ ions in aqueous medium. The MOF was characterized by X-ray powder diffraction, infrared spectroscopy, gas sorption and thermogravimetric analyses. The isophthalate ligand in CAU-10 was functionalized by the hydrazine group to make the acidic –NH protons easily available to the CN⁻ ions. Indeed, the activated compound (1′) showed highly selective and sensitive responses to CN⁻ ions over other common anions with a detection limit of 0.48 μM. A rapid fluorescence enhancement was observed for 1′ with a large spectral shift (Δλ = 30 nm) in the presence of CN⁻ ions in aqueous solution with the development of visible green fluorescence under a UV lamp. Due to the excellent detection performance to CN⁻ by 1′ in aqueous medium, the material was further used for CN⁻ detection in real water samples. The fluorescence increment with a large blue shift is attributed to the cyanide-induced deprotonation of the –NH group, which was confirmed by ¹H NMR titration measurements. The initial photo-induced electron transfer (PET) process is prohibited by this deprotonation, which causes the fluorescence enhancement. Time-resolved fluorescence lifetime measurements suggest that 1′ can also act as a lifetime based CN⁻ sensor. Finally, the CN⁻ sensing ability of 1′ inside living RAW 264.7 macrophages was demonstrated through live-cell imaging investigations.