Search Results (672)

Electrochemical water splitting for hydrogen production is an important path for the preparation of green hydrogen. However, the sluggish kinetics and high energy consumption of the anode oxygen evolution reaction (OER) have restricted its development. The hydrazine oxidation reaction (HzOR), with its low theoretical potential, fast kinetics, clean products, and the ability to simultaneously treat hydrazine-containing wastewater, has emerged as an ideal anode reaction to replace OER. Transition metal phosphides (TMPs) have shown noble-metal-like activity in HzOR catalysis due to their tunable d-band electronic structure, abundant active sites, high conductivity, and structural stability, making them highly promising non-noble metal catalysts. However, most existing reviews focus on the catalytic performance of TMPs in general hydrogen evolution reaction (HER)/OER systems or merely briefly mention HzOR as one of many anode reactions. Therefore, this review aims to comprehensively and systematically elaborate on the design strategies of TMPs catalysts for hydrazine-assisted electrolytic water splitting for hydrogen production and their applications in HzOR, deeply discuss the current progress, challenges, and future directions, and provide references for the development and industrial application of low-cost, high-efficiency, and high-stability hydrazine-assisted hydrogen production catalysts. Full article

Traditional hypergolic propellants, such as hydrazine derivatives combined with nitrogen tetroxide, present severe toxicity, operational, and environmental hazards. High-test peroxide has emerged as a leading green oxidiser replacement due to its low volatility, high density, and benign decomposition products. This review comprehensively analyses recent advancements in HTP-based hypergolic fuel formulations, categorising them into three major emerging families: catalytically-promoted, reactive, and ionic liquid-based systems. By evaluating key parameters such as ignition delay times, specific impulse and toxicity, this work identifies a clear technological shift from fundamental chemical screening to increasingly more mature solutions. While historical targets defined hypergolicity below 100 ms, recent advanced formulations routinely achieve it under 10 ms requiring minimal additive concentrations (<5 wt%), directly competing with legacy systems. Furthermore, this review highlights critical open challenges that limit commercial adoption, including the long-term storage stability of catalytic blends, high toxicity of reactive systems, and the lifecycle toxicity and high cost of frequently employed ionic liquids. Ultimately, it is concluded that rather than a single universal replacement, the future of green hypergolic propulsion lies in a plurality of solution, where each family is tailored to specific niches defined by mission requirements and cost structures. Full article

This investigation focused on isoniazid (INH)—saccharin (SAC) salts. One hydrate and one anhydrous INH-SAC salt form were synthesized and characterized spectroscopically by Raman and infrared spectroscopy. Solvent (methanol, acetone, acetonitrile)-assisted synthesis in the presence of water, or in water, resulted in production of the monohydrated form of the salt (MH: (INH+H)⁺/(SAC–H)⁻.H₂O). The anhydrous form (A: (INH+H)⁺/(SAC–H)⁻) was obtained using the same synthesis method but in the absence of water or, together with the hydrate, in the presence of traces of water. Differential scanning calorimetry studies revealed that the hydrate can be converted into the anhydrous form of the salt upon heating, with the latter melting at a T_m (onset) of 131.7 ± 0.5 °C. Melting was followed by a reaction between isoniazid and saccharin leading to saccharin ring opening and formation of a new covalent hydrazide–amide derivative, via nucleophilic acyl substitution at the saccharin carbonyl. The newly formed adduct, 2-[2-(pyridine-4-carbonyl)hydrazine-1-carbonyl] benzene-1-sulfonamide, melts at T_m (onset) = 204.4 ± 0.5 °C. The crystal structures of the hydrate and of the anhydrous form were determined by single-crystal X-ray diffraction, and the dominant intermolecular interactions in the crystalline INH-SAC salts were evaluated using Hirshfeld surface analysis. To complement the experimental results, density functional theory (DFT) calculations were performed both on relevant isolated structural units and on the two salts, employing fully periodic DFT methods. Full article

The development of sustainable electrocatalysts for clean energy by modifying biomass-derived activated carbon with nitrogen and transition metals is presented. Activated carbon (AWC) material was obtained using alder wood char as a precursor, while nitrogen and cobalt or copper nanoparticles were incorporated with the aim of creating efficient materials for hydrazine oxidation (HzOR) and direct hydrazine–hydrogen peroxide fuel cells (DHHPFC, N₂H₄–H₂O₂). The composition, structure, and surface morphology of the created materials were examined using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), and inductively coupled plasma optical emission spectroscopy (ICP-OES). The activity of the AWC, AWC–Co–N, and AWC–Cu–N catalysts for HzOR was investigated using cyclic voltammetry (CV) and linear sweep voltammetry (LSV). N₂H₄–H₂O₂ fuel-cell tests were performed by applying the catalysts as both the anode and cathode. It was found that all materials retained a hierarchical porous carbon framework, while metal incorporation altered surface compactness. Cobalt doping produced well-dispersed Co nanoparticles and abundant Co–N–C coordination sites, whereas Cu introduction resulted in moderately compact structures with uniformly distributed Cu-based nanoparticles. Electrochemical measurements demonstrated that both metal dopants enhanced HzOR activity, with the catalytic performance following the order of AWC–Co–N > AWC–Cu–N > AWC. Fuel-cell testing further confirmed this trend: AWC–Co–N achieved the highest maximum power density (30.4 mW cm⁻²), outperforming AWC–Cu–N (17.7 mW cm⁻²). These results identify AWC–Co–N as a highly effective bifunctional electrocatalyst for DHHPFCs. Full article

Lubricants contain various types of additives, with corrosion and rust inhibitors being some of the most important. Due to the importance of 2,5-Dimercapto-1,3,4-thiadiazole (DMTD) in the field of corrosion inhibitors, we used it as a key intermediate to synthesize a series of 4-thiazolidinone and 4-imidazolidinone derivatives. This work also includes performing the reaction of DMTD with ethyl chloroacetate, which produced the corresponding ester, followed by the conversion into a hydrazide derivative using hydrazine hydrate. The next step is the condensing of the yielded hydrazide with various aromatic aldehydes yielding Schiff bases, which were subjected to cyclization by means of mercapto acetic acid and ethyl glycinate to produce the target 4-thiazolidinone and 4-imidazolidinone derivatives, respectively. FT IR, ¹H NMR, and ¹³C NMR spectroscopies were involved to confirm the structures of these derivatives. The synthesized derivatives have been evaluated as copper corrosion and rust inhibitors for medium lubricants in accordance with ASTM-D130 and ASTM-D665 standards. Interestingly, some lubricant blends of the synthesized derivatives showed good performance as copper corrosion and rust inhibitors. Full article

A new series of isoxazole-fused thiazole–oxazole derivatives (11a–n) was rationally designed and synthesised with the aim of developing potent carbonic anhydrase (CA) I and II inhibitors. The synthesis was achieved in five steps starting from 4-bromoacetophenone, involving key intermediates such as hydroxylamine hydrochloride, hydrazine hydrate, thioisocyanate, and various phenacyl bromide derivatives, using ethanol, triethylamine, tetrahydrofuran (THF), and dimethylformamide (DMF) as solvents. The synthetic route included the formation of a β-ketoester, isoxazole ester, hydrazine adduct, thiourea derivative, and, ultimately, a thiazole ring. The structures of the final compounds were confirmed by ¹H-NMR, ¹³C-NMR, IR spectroscopy, and elemental analysis. All compounds were examined as inhibitors of human carbonic anhydrase (hCA) I and II, and all of them inhibited hCA I and hCA II. Kinetic investigation results revealed that these compounds inhibited hCA I and hCA II in a non-competitive manner. To further explore the molecular basis of their inhibitory activity, in silico studies, including molecular docking and 300 ns molecular dynamics (MD) simulations, were carried out against both CA I and CA II isoforms. These simulations provided detailed insights into the dynamic behaviour, stability, and key binding interactions of the compounds within the enzyme active sites, supporting their potential as promising carbonic anhydrase inhibitors. Full article

A TiO₂/hydrazine system was investigated as a proof-of-concept platform for coupling chemical CO₂ capture with light-driven H₂ evolution under UV irradiation. Hydrazine served as the CO₂ capture agent, leading to the formation of carbamate-type intermediates, while TiO₂ acted as the photoresponsive solid. FT-IR, UV-Vis, and mass spectrometry analyses supported carbamate formation after CO₂ uptake and confirmed H₂ generation during irradiation, reaching a maximum of 33.2 μmol under the conditions evaluated. Deuterated experiments showed no detectable HD or D₂, indicating that H₂ evolution predominantly proceeded via hydrazine dehydrogenation rather than direct water splitting. On the basis of the available spectroscopic evidence, a tentative pathway involving carbamate intermediates and nitrogen-containing oxidation products is proposed. However, key control experiments required to confirm a strictly photocatalytic origin of H₂ evolution were not performed in the present exploratory study. Therefore, the observed behavior is more appropriately interpreted as preliminary photoinduced reactivity in a TiO₂/hydrazine/CO₂ system rather than definitive proof of a fully established photocatalytic mechanism. Overall, the results establish a preliminary proof of concept, while the limitations related to control experiments, product identification, quantification, and reproducibility are recognized. Full article

Sustained cislunar logistics operations, including recurring support of the Lunar Gateway at EML1 and EML2, impose demanding propulsion requirements, including high ΔV budgets, restart capability, and long-duration propellant storage, which conventional propulsion approaches struggle to meet efficiently at scale. This study presents a novel cislunar mission architecture based on nuclear thermal propulsion (NTP), operating at a specific impulse of 900 s with liquid hydrogen as propellant and a hydrazine Reaction Control System (RCS) for proximity and docking maneuvers. The architecture is evaluated analytically through sequential application of the Tsiolkovsky rocket equation across two mission scenarios: a direct logistics transfer to EML1 (Scenario A) and a two-burn Gateway staging transfer from EML1 to EML2 (Scenario B), using a launch mass of 9000 kg, a 5% ΔV margin, and deterministic ΔV values of 3164 m/s for LEO→EML1, 160 m/s for EML1→EML2, and 37.36 m/s for RCS operations. The proposed architecture achieves a total propellant mass below 3044 kg and a total delivered mass between 5956 kg and 6071 kg across both scenarios. These results establish NTP as a technically credible foundation for scalable and sustainable cislunar transportation, with broad implications for the development of a permanent lunar economy. Full article

Colorectal cancer (CRC) is the third most prevalent cancer globally. TASK-1, encoded by the KCNK3 gene, is emerging as a putative target in cancer; it regulates resting membrane potential, cell proliferation, and apoptosis. A series of 27 novel xanthene derivatives, modified at position 9, were synthesized via azide coupling of 2-(9H-xanthen-9-yl)acetohydrazide with selected amines and amino acids, followed by hydrazine-mediated conversion to the corresponding hydrazides. The cytotoxic activity of selected compounds (5a–5g, 6a–6h, 7b, 7f–7h) was evaluated against the HCT-116 cell line in vitro. In addition, molecular docking and molecular dynamics simulations were performed to investigate binding interactions and assess the stability of the protein–ligand complexes. Several compounds (5f, 5g, 6c, 6d, 6f, 6g, 7b, 7f, and 7h) exhibited moderate cytotoxic activity against HCT-116 cells (IC₅₀: 66.97–99.62 µM), compared to cisplatin (IC₅₀: 18.25 µM). Compound 7h demonstrated pronounced antiproliferative effects, evidenced by DAPI staining showing chromatin condensation and apoptotic body formation, along with a marked reduction in cell count and coverage. Molecular docking indicated favorable binding within the TASK-1 potassium channel, and molecular dynamics simulations confirmed the stability of the protein–ligand complex, with consistent interactions, including a key hydrogen bond with Asn240. These findings support 7h as a promising lead candidate. These findings identify xanthene-based derivatives as promising lead compounds for further optimization as TASK-1-targeted therapeutic candidates in colorectal cancer. Full article

Driven by the demand for miniaturization, high capacitance, and enhanced reliability in high-performance multilayer ceramic capacitors (MLCCs), the continuous thinning of inner electrode layers imposes increasingly stringent requirements on the size, distribution, morphology, and dispersion of nano-nickel powders. We systematically investigate how functional additives regulate the nucleation, growth, and microstructural evolution of nano-nickel synthesized via hydrazine-driven liquid-phase reduction of nickel sulfate. The results demonstrate that the alkanolamine complexing agent (TAC) significantly refines the average particle size and morphology of the nano-nickel through coordination effects. Furthermore, inorganic sulfur salts (ISP), acting via surface adsorption to passivate growth sites and provide catalytic effects, enable a precise and continuous reduction in the average particle diameter from 330 nm down to 60 nm at a mere trace dosage of ~10⁻⁷ mol/L. Regarding dispersion optimization, highly dispersed face-centered cubic (FCC) nano-nickel was successfully prepared by introducing multidentate carboxylate (NNA). High-resolution transmission electron microscopy (HRTEM) was employed to unveil, for the first time, the crystallographic origin of the anomalous surface protrusions typically observed in conventional reaction systems. We confirmed that the family of $\left\{10\overline{1}0\right\}$ crystal planes within these regions, which exhibits interfacial angles of 58.7° and 58.3°, corresponds to a thermodynamically metastable hexagonal close-packed (HCP) nickel phase originating from atomic stacking faults induced by rapid growth kinetics. To address this microstructural defect, a thioether-based amino acid (TAA) was introduced. TAA effectively suppresses the anisotropic growth of the metastable HCP phase through the strong steric hindrance of its long side chains and its selective adsorption onto high-energy facets. Full article

In the present work, a novel series of eleven sulfonate derivatives with potent inhibitory activity against butyrylcholinesterase (BChE) is reported. Of these, compounds 2-[(E)-(2-Benzoylhydrazinylidene)methyl]phenyl 5-(dimethylamino)naphthalene-1-sulfonate (5c, IC₅₀ = 1.11 µM) and tert-butyl (2E)-2-[(2-{[5-(dimethylamino)naphthalene-1-sulfonyl]oxy}phenyl)methylidene]hydrazine-1-carboxylate (5b, IC₅₀ = 11.51 µM) exhibit stronger inhibitory activity than rivastigmine, the reference compound, and exhibit high selectivity for BChE over AChE (e.g., selectivity index 57 for 5c). Interestingly, compound 5c also exhibited anti-inflammatory effects, which is important for potential therapeutic applications, especially in Alzheimer’s disease. These new compounds were designed through a structure-based approach using molecular modeling techniques (docking, molecular dynamic (MD) simulations, and QTAIM (quantum theory of atoms in molecules) calculations). The most promising compounds show no detectable toxic effects and satisfy Lipinski’s rule of five, indicating that they represent attractive starting structures for the design of new derivatives acting as specific BChE inhibitors. In addition, our results indicate that relatively simple computational techniques such as docking calculations and toxicity prediction programs can be valuable when properly used in the search of new candidates for this particular target. Docking calculations show that the more active compounds of this series reach the bottom region of the gorge interacting with residues within the active site of BChE. However, our data further suggest that the use of more precise techniques, such as MD simulations and QTAIM analysis, is necessary to obtain detailed insight into ligand–enzyme interactions. Regarding QTAIM calculations, they demonstrate that such computations are very useful to evaluate the molecular interactions of the different molecular complexes. In summary, we report a new series of sulfonate derivatives as promising starting structures for the development of new selective BChE inhibitors. Full article

Background/Objectives: Antimicrobial resistance (AMR) is an escalating global threat driven by antibiotic misuse and bacterial adaptation. Efflux pumps are major contributors to multidrug resistance in Escherichia coli, as they expel antibiotics and reduce their intracellular activity. This study examined efflux-mediated resistance in extended-spectrum beta-lactamase (ESBL)-producing E. coli and evaluated the potential of several efflux pump inhibitors (EPIs)—promethazine (PMZ), thioridazine (TZ), carbonyl cyanide m-chlorophenyl hydrazine (CCCP), reserpine (RES), and phenyl-arginine-β-naphthylamide (PAβN)—as therapeutic adjuncts. Methods: Antibacterial and anti-biofilm activities of EPIs were tested using broth microdilution, real-time fluorimetry, and crystal violet assays, while ceftriaxone–PMZ interactions were assessed by checkerboard analysis. Results: TZ and CCCP showed strain-specific antibacterial activity, whereas PMZ, RES, and PAβN did not exert any effect. PMZ, TZ, and especially CCCP effectively inhibited efflux pump function, while RES and PAβN were less active. Biofilm inhibition varied between strains, with PMZ and TZ producing moderate reductions. We observed a quite weak synergism between ciprofloxacin, ceftriaxone, and PMZ; however, the result was not significant. Conclusions: Overall, the results highlight the central role of efflux pumps in ESBL-producing E. coli and indicate that EPIs can reverse resistance (e.g., PMZ) and exhibit potent anti-biofilm activity and show additive interactions with antibiotics. However, further studies are needed to optimize their safety, pharmacokinetics, and antibiotic pairing for potential clinical use. Full article

Background/Objectives: Targeting ABL tyrosine kinase (TK) remains a cornerstone of chronic myeloid leukemia (CML) therapy. Methods: In this study, a series of novel 4-((2-(4-(aryl)thiazol-2-yl)hydrazineylidene)methyl)-N,N-diphenylaniline derivatives (1–12) were synthesized through the reaction of 2-(4-(diphenylamino)benzylidene)hydrazine-1-carbothioamide (intermediate A) with substituted 2-bromo-1-arylethanones. Cytotoxic activity was evaluated in K562 CML cells using the MTT assay. The most active compound was further assessed in HL-60 acute myeloid leukemia (AML) cells and healthy peripheral blood mononuclear cells (PBMCs). Apoptosis induction was analyzed by Annexin V/ethidium homodimer staining, while ABL TK inhibition was determined using the ADP-Glo kinase assay. Molecular docking studies were performed to investigate binding interactions within the ATP-binding site of ABL TK, and pharmacokinetic properties were also predicted. Results: Intermediate A demonstrated superior antiproliferative activity compared to derivatives 1–12 and exhibited cytotoxicity comparable to imatinib in K562 cells (IC₅₀ = 6.15 ± 1.26 µM vs. 5.14 ± 1.44 µM, respectively). In HL-60 cells, intermediate A showed an IC₅₀ of 12.04 ± 1.70 µM, similar to imatinib. Notably, intermediate A displayed enhanced selectivity toward K562 cells over PBMCs (SI = 12.9) relative to imatinib (SI = 6.2). The compound significantly induced apoptosis in K562 cells and inhibited ABL TK activity. Docking studies revealed a distinct binding orientation within the ATP-binding pocket of ABL TK. The compound showed acceptable predicted physicochemical and ADME characteristics based on in silico analysis. Conclusions: Intermediate A emerges as a significant anti-CML candidate exhibiting potent cytotoxic, apoptotic, and moderate ABL TK inhibitory activity, together with a favorable selectivity profile. Full article

To identify fungicide lead compounds with novel scaffolds and high efficacy, 33 novel bacillamide–acylhydrazone derivatives were successfully designed and synthesized by using a molecular hybridization strategy. The bioassay results showed that most of the target compounds exhibited promising inhibitory activity against B. cinerea. Among them, compound BAD-15 displayed the most potent antifungal activity with an EC₅₀ value of 6.725 μg/mL. Furthermore, preliminary SAR analysis revealed that the R group in hydrazine fragments exerts a significant influence on antifungal potency. Studying the molecular mechanism by morphological observation and transcriptome analyses revealed that BAD-15 may inhibit the activity of copper ion transmembrane transporters, leading to disrupted copper ion homeostasis and subsequent suppression of fungal growth. The present work indicates that bacillamide–acylhydrazone has potential as a novel scaffold for the development of fungicides, and compound BAD-15 may serve as a potential lead compound for the further development of novel fungicides. Full article

With the increasing deployment of lithium iron phosphate (LiFePO₄) batteries in electric vehicles and energy storage systems, the recycling of these materials has become an urgent necessity. Specifically, the reclamation of lithium iron phosphate cathode materials presents a significant challenge in the recycling process. In this study, we proposed an efficient low-temperature hydrothermal direct regeneration method aimed at repairing lithium vacancies and Fe/Li inversion defects in spent lithium iron phosphate resulting from prolonged cycling. By using this method, spent lithium iron phosphate was successfully regenerated through a hydrothermal process conducted at 80 °C for 6 h, utilizing hydrazine hydrate (N₂H₄·H₂O) as a potent reducing agent and lithium hydroxide (LiOH·H₂O) as the lithium source. X-ray diffraction (XRD) analysis, coupled with Rietveld refinement, revealed a substantial reduction in the concentration of Fe/Li anti-site defects in the spent material, decreasing from 8.8% to 3.3% following regeneration. Consequently, the electrochemical performance was significantly restored. The initial specific discharge capacity increased from 118.0 mAh·g⁻¹ to 150.3 mAh·g⁻¹, and the capacity retention after 100 cycles (at 1 C) improved from 67.5% to 90.7%. The hydrothermal regeneration process introduced in this work effectively repairs the material structure and restores the active valence state of iron, thereby significantly enhancing lithium-ion diffusion and electron transport capabilities. This approach constitutes a technically viable solution for the efficient, environmentally friendly, and cost-effective recycling of spent lithium-ion batteries. Full article