Hydrazine (N2H4) is a crucial chemical raw material extensively utilized in chemical production. However, due to its volatility, water solubility, and high toxicity, both the gaseous form and aqueous solution of N2H4 pose significant environmental risks by causing severe pollution that can adversely impact plants, microorganisms, and human health. Therefore, accurate detection of N2H4 in the environment is imperative for safeguarding public health. In this study, we synthesized a ratiometric fluorescent probe (BCaz-Cy2) based on Carbazole and Hemicyanine groups. This probe exhibits simple synthesis procedure, rapid response time, high sensitivity and selectivity as well as remarkable detection signals. It enables effective detection of N2H4 in various matrices such as water, food, soil and plant samples thereby significantly expanding the scope of applications for N2H4 probes.

Devising of materials that afforded dual applicability in decontamination and pollutant detection were still a towering challenge owing to the increasing flux of discharge toxic contaminants over the years. Herein, the NiFe2O4 nanoparticles-loaded on cube-like SrTiO3 (NiFe2O4/SrTiO3) composite was fabricated by a two-step hydrothermal approach providing remarkable photocatalytic treatment and electrochemical sensing of noxious pollutants in wastewater. The material traits of the fabricated composite were scrutinized by myriad characterization approaches. The NiFe2O4/SrTiO3 hybrid material demonstrated high surface area of 19.81 m2/g, adequate band gap energy of 2.75 eV, and prominent photoluminescence characteristics. In the presence of visible light, the NiFe2O4/SrTiO3 exhibited profound photocatalysis capability to eliminate sewage effluent-bearing chlortetracycline hydrochloride (CTCH) with 88.6% COD removal in 120 min, outperforming other pure materials. Meanwhile, the toxicity examination of effluent, the possible degradation pathway of CTCH and the proposed photocatalysis mechanism were also divulged. More importantly, the glassy carbon electrode was modified with synergized NiFe2O4/SrTiO3 (NiFe2O4/SrTiO3-GCE) was adopted for the precise quantification of Hydrazine (Hz). The NiFe2O4/SrTiO3-GCE obeyed first-order response for the Hz detection within the range of 1-10 mM: cyclic voltametric: limit of detection (LOD) of 0.119 μM with sensitivity of 18.9 μA μM-1 cm-2, and linear sweep voltametric: LOD of 0.222 μM with a sensitivity of 12.05 μA μM-1 cm-2. The stability and interference of modified electrode were also inspected. This work furnished valuable insights to yield a composite with the prominent S-scheme heterojunction system for quenching of charge carrier recombination and consequently contributing to the future realization into the domains of environmental clean-up and toxic chemical detection.

BACKGROUND: The natural product paeonol is a rich and sustainable natural bioresource, and its derivatives have various unique biological efficacy. As is well known, Schiff bases are a class of organic compounds with a wide range of biological activities, including anti-fungal, insecticidal, anti-viral, and nematicidal.
RESULTS: To discover biorational natural product-based pesticides, nine intermediates (2-10), 12 sulfonylhydrazones (11a-11c, 12a-12c, 13a-13c, and 14a-14c) and 20 benzylidene hydrazones (18a-18r, 19a, and 20a) were synthesized by structural modification of paeonol, and their structures were characterized by proton nuclear magnetic resonance (1H NMR), carbon-13 (13C) NMR, and high-resolution mass spectrometry (HRMS). The stereochemical configurations of compounds 14a, 18d, and 18r were unambiguously confirmed by single-crystal X-ray diffraction. Furthermore, bioactivities of these compounds as anti-oomycete, anti-fungal, and nematicidal agents against three serious agricultural pests, Phytophthora capsici, Fusarium graminearum, and Heterodera glycines were evaluated. Among all tested compounds: (i) compound 7 exhibited promising anti-oomycete against Phytophthora capsici, with a half maximal effective concentration (EC50) value of 15.81 mg L-1; (ii) compounds 2, 7, 10, and 19a displayed promising anti-fungal against F. graminearum, with EC50 values of 12.22, 14.72, 23.39, and 33.10 mg L-1, respectively; (iii) ten compounds (12a-12c, 14c, 18g-18j, 18m, and 19a) showed significant nematicidal activity against H. glycines, with median lethal concentration (LC50) values all less than 30.00 mg L-1. Especially for compound 18g, its LC50 value is the smallest, at 12.65 mg L-1.
CONCLUSIONS: The research results indicate that introducing nitro groups at the C5 position of paeonol, or introducing halogens at both C5 and C3 positions, can significantly enhance its biological activity against Phytophthora capsici, F. graminearum, and H. glycines. © 2024 Society of Chemical Industry.

Hydrazine (N2H4) has toxic effects on the environment. Although a variety of reactive probes have been used to identify hydrazine, practical applications required continuous development of hydrazine fluorescent probes with improved performance. Here, we applied the neighboring group participation (NGP) to the design of a fluorescent probe for hydrazine. The probe exhibited a rapid response to N2H4 and strong anti-interference ability, with detection limited to 0.031 μmol/L. Theoretical calculation showed that the energy barrier could be reduced by NGP. The cyclic intermediate formed by the indole ring and the α-ester carbonyl group significantly reduced the activation energy of the reaction. Practically, the probe could detect hydrazine in actual water samples.

Hydrazine (N2H4) and bisulfite (HSO3-) detection methods are urgently needed due to its harmful to the human health and environment safety. Herein, we reported a dual-response fluorescence probe EPC, which is capable of sequential detection of N2H4 and HSO3- by two different fluorescence signals. The probe EPC itself showed yellow florescence. In presence of N2H4, probe EPC exhibited an obviously fluorescence change (from yellow to green). However, a new addition product came into being after probe EPC mixed with HSO3-, followed with weak yellow emission. More important, probe EPC exhibited excellent fluorescence response properties for N2H4 and HSO3-, such as high sensitivity (0.182 µM for N2H4, 0.093 µM for HSO3-), rapid response (55 s for N2H4, 45 s for HSO3-), excellent selectivity and anti-interference performance. The sensing mechanisms for N2H4 and HSO3- were proved by 1H NMR and MS spectra. Practical applications were studied. EPC based test paper can be utilized for quantitative detecting N2H4 in actual water samples. And, probe EPC has been successfully applied to recognize N2H4 contaminant in soil samples. Moreover, EPC has great potential to be used to detect HSO3- in real food samples.

7-Bromo-4-chloro-1H-indazol-3-amine is a heterocyclic fragment used in the synthesis of Lenacapavir, a potent capsid inhibitor for the treatment of HIV-1 infections. In this manuscript, we describe a new approach to synthesizing 7-bromo-4-chloro-1H-indazol-3-amine from inexpensive 2,6-dichlorobenzonitrile. This synthetic method utilizes a two-step sequence including regioselective bromination and heterocycle formation with hydrazine to give the desired product in an overall isolated yield of 38-45%. The new protocol has been successfully demonstrated on hundred-gram scales without the need for column chromatography purification. This new synthesis provides a potential economical route to the large-scale production of this heterocyclic fragment of Lenacapavir.

This work reports the development of novel curcuminoid-based electrochemical sensors for the detection of environmental pollutants from water. In this study, the first set of electrochemical experiments was carried out using curcumin-conjugated multi-walled carbon nanotubes (MWCNT-CM) for 1,4-dioxane detection. The MWCNT-CM/GCE showed good sensitivity (103.25 nA nM-1 cm-2 in the linear range 1 nM to 1 µM), with LOD of 35.71 pM and LOQ of 108.21 pM. The second set of electrochemical experiments was carried out with bisdemethoxy curcumin analog quantum dots (BDMCAQD) for hydrazine detection. The BDMCAQD/GCE exhibited good sensitivity (74.96 nA nM-1 cm-2 in the linear range 100 nM to 1 µM), with LOD of 10 nM and LOQ of 44.93 nM. Thus, this work will serve as a reference for the fabrication of metal-free electrochemical sensors using curcuminoids as the redox mediator for the enhanced detection of environmental pollutants.

Hydrazine (N2H4), a crucial chemical raw material, enhances people\'s lives and fosters human progress. Hydrazine usage or leakage has caused environmental contamination, affecting water, soil, and living beings. Hydrazine simultaneously presents a possible risk to human health due to its carcinogenic properties. Thus, quick and precise detection of hydrazine is crucial in environmental studies and biological contexts. We prepared a red-emitting fluorescence turn-on probe (XT-HZ) to detect hydrazine specifically. The probe has a low detecting limit for hydrazine (63 nM) with excitation wavelength at 570 nm and emission wavelength at 625 nm. Besides, the probe XT-HZ had excellent water solubility, high selectivity, and good sensitivity for detecting hydrazine. Finally, probe XT-HZ was applied in the imaging of N2H4 in living cells, zebrafish and environmental water samples.

In the realm of synthetic organic chemistry, by using a one-pot sequential combination of MCR, it is possible to manufacture chemical commodities (fine chemicals, agrochemicals, and pharmaceutical substances) that enhance our quality of life while generating less waste materials and increasing economic advantages. With this motivation, using a \"one-pot\" method with multiple components, we present a relatively simple way to make stereoselective substitute 2H-indazole analogues for this study. Firstly, functionalised 3-bromo-4-((methylthio)methyl) derivatives were produced using DMSO as both a carbon source and a solvent, in conjunction with TMSOTf as the Lewis acid promoter. These derivatives were then utilised in the synthesis of 2-H-indazole derivatives with an up to 80% yield using t-Bu3PHBF4 as the ligand and Cs2CO3 as the base, in the presence of a Pd catalyst at 100°C in an airtight tube. The phenyl ring is endowed with an electron-releasing group situated at position C-6, which efficiently synthesises several 2-H-indazol derivatives with cost-efficient and noteworthy yields by using this method. A comparative analysis of a number of halogen derivatives was also undertaken, using a variety of solvents that were classified according to their halogen group. To confirm the structures of the synthesised target compounds, spectrometric analysis (1H NMR, 13C NMR, and LCMS) was performed.

This work established a newly designed and synthesized carbazole N-phenyl π-conjugated vinyl malononitrile (CPM) fluorescent sensor, which showed typical and remarkable redshift emission properties with different polarity index solvents. Investigative probe CPM is colorimetric and fluorimetric ultrafast and ultrasensitive detection of hazardous hydrazine in an aqueous medium. Furthermore, CPM showed colorimetric and fluorometric responses to interference tests with other amines and high selectivity for detecting hydrazine without interference with other amines in colorimetric and fluorimetric methods. This probe CPM for hydrazine was as low as the lower detection limit value of 2.21 × 10- 8 M. The probe CPM expects significant attention due to its simplicity and cost-effectiveness in detecting hazardous hydrazine. UV-vis, PL, NMR, and MS spectra confirmed the mechanism of probe CPM detection of hazardous hydrazine. However, making a piece test kit attractive for practical hydrazine vapor leak-detection applications is easy. This study can be applied to many pipeline gas transmission industries and transportation facility sectors.