ChemistrySelect最新文献

Nanotechnology has the potential to provide significant solutions to challenges across various fields, including environmental remediation, catalysis, and medicine. Titanium dioxide (TiO₂) nanoparticles have attracted attention due to their photocatalytic and biomedical applications. This study adopted an ultrasonic-assisted synthesis method for TiO₂ nanoparticles using Pistacia khinjuk leaf extract. The nanoparticles were fabricated by reacting a titanium isopropoxide precursor solution with the Pistacia khinjuk leaf extract. The UV–vis spectra revealed a strong absorption peak at 380 nm. X-ray diffraction analysis confirmed the hexagonal crystalline structure of TiO₂ (rutile) with a particle size of ∼35 nm. FTIR spectra confirmed Ti–O stretching vibrations at around 474 cm⁻¹. The TiO₂ nanoparticles exhibited significant cytotoxic effects on HeLa and HEK-293 cell lines, showing selective toxicity towards cancer cells. Additionally, the TiO₂ nanoparticles demonstrated 92.33% photocatalytic activity of Congo red under UV exposure for over 150 min. The TiO₂ nanoparticles also exhibited significant antioxidant activity (56.74% DPPH scavenging at 100 µg/mL) and enhanced antibacterial activity against Staphylococcus aureus and Bacillus pumilus, surpassing the extract alone. This work presents an effective, simple, and eco-friendly method for synthesizing TiO₂ nanoparticles and assessing their potential for various medical and industrial applications.

Recycled wasted palm tree leaf was utilized as an adsorbent for rhodamine B (RhB) dye and antimicrobial agent. The palm leaf surface was modified by coating it with silver oxide nanoparticles to improve its antibacterial properties. Characterization of both coated and uncoated palm leaf was performed using Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), thermo-gravimetric analysis (TGA), and scanning electron microscopy (SEM). Adsorption behavior was investigated for both coated and uncoated palm leaf. Different factors such as effect of dose, pH, time, and temperature were studied. Moreover, adsorption equilibrium isotherms were analyzed by Langmuir, Freundlich, Temkin, Halsey, and Dubinin–Radushkevich (D–R) models. The best fit for experimental data was shown by Harkin Jura model. The maximum adsorption capacity was found to be 2.56 mg g⁻¹. The kinetics analysis of the experimental data was done using pseudo-first-order, pseudo-second-order, Elovich model, and intra-particle mass transfer diffusion kinetic models. Pseudo-second-order kinetic model described the kinetics accurately for the adsorption process. Thermodynamic parameters were calculated showing that the adsorption process was spontaneous adsorption processes (−ΔG°) and endothermic (+ΔH°). Antimicrobial activity also investigated showing remarkable results of silver oxide nanoparticles coated palm leaf.

This study aimed to analyze the adsorption behavior of Fe(III) ions from aqueous solutions onto naturally derived chitosan beads functionalized with esterified vanillin–cinnamate (1). The produced material was characterized by FTIR, XRD, and SEM–EDX analyses. Kinetic and equilibrium studies were employed to evaluate the effects of solution pH, contact time, and adsorbent dosage in a batch system. The optimal situations for Fe(III) adsorption were found to be a solution pH of 6, an adsorbent dosage of 20 mg, and a contact time of 60 min. The adsorption capacity and desorption efficiency based on Langmuir were 135.85 mg/g and 83.17% for Fe(III) ions. Chitosan beads functionalized with ester vanillin–cinnamate (1) demonstrated effective performance as a bioadsorbent for the removal of Fe(III) ions by aqueous solutions. This study underscores the potential of chitosan-based materials as efficient adsorbents for wastewater treatment applications.

Arsenic contamination in aquatic systems presents severe environmental and health hazards and can result from both human activities and natural occurrences. The focus of the current study was to investigate arsenate adsorption onto FePO₄, unmodified activated carbon (VAC), and iron-impregnated activated carbon (Fe-AC) to create an efficient arsenic-removal adsorbent. BET surface area analysis showed the highest surface area for VAC (525 m² g⁻¹), followed by Fe-AC (140 m² g⁻¹) and FePO₄ (80 m² g⁻¹) surface area, which decreased with increasing calcination temperatures owing to particle agglomeration. FTIR spectra confirmed the formation of Fe–O and Fe–OH bonds in Fe-AC, while XRD analysis confirmed that VAC exhibited amorphous behavior, and the calcination at 750 °C transformed the crystalline phase of FePO₄ and Fe-AC. The point of zero charge (PZC) trend followed Fe-AC > FePO₄ > VAC, in comparison to arsenate adsorption. The kinetic data best fitted to the pseudo-second order (PSO) model, suggesting chemisorption-controlled mechanisms, and the sharp equilibrium data fitted the Langmuir isotherm for monolayer adsorption. The adsorption capacities (qm) and Langmuir constants (K_L) decreased with increasing pH but were enhanced considerably with an increase in temperature. The thermodynamic parameters (ΔH° > 0, ΔG° < 0, ΔS° < 0) confirmed that the process was endothermic, spontaneous, and feasible. Activation energy values complement the stronger adsorption affinity of Fe-AC compared with FePO₄. Both adsorbents removed almost 100% of arsenic from real water samples; however, as Fe-AC was able to show higher performance based on enhanced surface reactivity and better iron dispersion, it would be favorable in adsorption. The overall findings suggest that Fe-AC holds a good promise as a sustainable and regenerable adsorbent for arsenic remediation in water treatment applications.

A previously undescribed isoflavone derivative, abyssinicanone (1), and two known flavonoids, including abyssinoflavanone V (2) and sigmoidin C (3), were isolated from Erythrina abyssinica stem bark. Abyssinicanone's structure was determined by spectroscopic analyses and x-ray crystallography. The isolated compounds were screened against bacterial and fungal strains. Moreover, antioxidant activity was performed using the DPPH free radical test, and a 3-day uterotrophy assay was employed to assay estrogenic activity in rats. Abyssinicanone showed moderate inhibitory activity against a spectrum of bacteria with a MIC of 125 µg/mL. Compound 1 incubation with three fungi inhibited their growth with MIC values of 31.25, 62.50, and 125 µg/mL, respectively. Abyssinicanone exhibited antioxidant activity by scavenging DPPH free radicals with a radical scavenging percentage of 6.41% at 40 µg/mL. The treatment of ovariectomized rats with 2.5 mg/kg of abyssinicanone restored the hormonal decline caused by ovary ablation prior to treatment. The uterine weight loss and the vaginal epithelial height were also restored as compared with the negative control group. Rats treated with compound 1 did not induce an estrogenic response in the endometrium and in mammary glands. Overall, these results demonstrate the antimicrobial, antioxidant, and estrogenic activities of abyssinicanone, a novel compound from Erythrina abyssinica stem bark.

Phosphine–phenolate nickel catalysts, based on [P, O] ligand, attracted much attention for its ability in catalyzing the copolymerization of ethylene with polar monomers. Herein, a series of tert-butyl substituted phosphine-phenolate nickel complexes were synthesized and exhibited good catalytic performance in ethylene polymerization. Simultaneously, the molecular weight of the polyethylene products can be altered by steric and electronic perturb. In the copolymerization of ethylene with tert-butyl acrylate, methyl 10-undecenoate and 6-chlorohex-1-ene, these phosphine-phenolate nickel catalysts yielded copolymers with tunable comonomer incorporation ratio (0.6-2.0 mol%).

The fluorescence quenching study of biphenyl (BIP) was carried out using carbon tetrachloride (CCl₄) and nitromethane (NM) in methanol (polar) and n-hexane (nonpolar) solvents at room temperature. The fluorescence quenching study was carried out using steady-state, time-resolved fluorescence spectroscopy as well as UV–vis absorption spectroscopy. The fluorescence quenching results of BIP in the presence of NM in methanol are found to be significant. This observation is well supported by measuring the lifetime of the prepared samples. The observed results of a decrease in fluorescence lifetime of BIP with quencher are due to collisional quenching. Quenching rate parameters in methanol and n-hexane with CCl₄ and NM have shown that the fluorescence quenching is well governed by the Stern–Volmer plot. The estimated probability of quenching per encounter “p” in both solvents was found to be greater than unity, which indicates the reaction of quenching is not solely controlled by material diffusion and may depend on the activation process. The activation energy “E_a” required for the quenching has been studied and found to be higher than the activation energy for diffusion “E_d.” The magnitudes of “p” and “E_a” play a vital role in the quenching mechanism in addition to material diffusion.

Cancer is a multifactorial disease, and proteasomes are established targets for chemotherapy in cancer treatment. Several covalent inhibitors are currently available on the market or in clinical use; however, these drugs often have unfavorable pharmacodynamic profiles due to the presence of electrophilic warheads. This can lead to mutations and overexpression of the proteasome, resulting in drug resistance. In this study, thiourea-based colchicine derivatives were designed, synthesized, and evaluated for their ability to inhibit the chymotrypsin-like activity of the β5 subunit in the proteasome, using a Jurkat cell lysate enriched with proteasomes. The in vitro proteasome inhibition assay revealed that the thiourea-based derivative CTU5, featuring a methoxy group at the para position, exhibited the highest activity, achieving 65.29% inhibition at 50 µM, compared to the well-known covalent inhibitor MG132. Additionally, a molecular docking investigation was performed to explore potential binding interactions. Furthermore, the in silico absorption, distribution, metabolism, and excretion (ADME) parameters suggested that CTU5 may possess drug-like properties and could be developed into an orally active pharmaceutical. Overall, these findings indicate that CTU5 has the potential to serve as a new scaffold and starting point for the development of novel, potent proteasome inhibitors in the future.

In this study, vermiculite (VMT), a naturally occurring layered silicate, was incorporated into a low-density polyethylene (LDPE) matrix at loading levels of 5 wt%, 7.5 wt%, 10 wt%, and 15 wt%. The composites were prepared by melt blending using a twin-screw extruder followed by injection molding. Thermal, mechanical, morphological and structural characterizations were conducted through thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), tensile and flexural tests, Izod notched impact testing, scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). TGA results indicated an increase in thermal degradation onset temperature from 357 °C (neat LDPE) to 389 °C (15 wt% VMT), confirming enhanced thermal stability. DSC analysis showed a slight reduction in crystallinity with increasing VMT content. The tensile and flexural moduli were improved proportionally with VMT loading, suggesting a stiffening effect, while elongation at break and impact resistance decreased, implying reduced ductility. SEM observations revealed good filler dispersion at low concentrations, but particle agglomeration and interfacial voids became evident at higher loadings. FTIR spectra confirmed the presence of VMT without any significant chemical interaction with the LDPE backbone. Overall, the incorporation of VMT enhances the rigidity and thermal resistance of LDPE composites, making them promising candidates for structural applications where dimensional stability and thermal performance are critical.

In this study, a new Schiff base-functionalized silane, compound 3, derived from 4-(pyridin-2-yl)benzaldehyde, was synthesized and comprehensively characterized using ¹H NMR, ¹³C NMR, and mass spectrometry. The optical properties of compound 3 were investigated via UV–visible and fluorescence spectroscopy, demonstrating high selectivity and sensitivity toward Ni²⁺ ion with minimal interference from other metal ions. Job's plot confirmed a 1:1 binding stoichiometry, while the binding constants were determined as 7.91 × 10⁷ M⁻¹ (Stern–Volmer) and 3.12 × 10⁷ M⁻¹ (Benesi–Hildebrand), indicating strong metal–ligand interactions. The limits of detection were exceptionally low: 0.17 (fluorescence) and 3.7 nM (absorption), supporting ultra-trace detection capability. The binding mechanism was further validated by ¹H NMR titration, mass spectrometry, and density functional theory calculations. Pharmacokinetic predictions via ADMET tools suggested favorable bioavailability, while antioxidant activity assays demonstrated significant radical-scavenging efficiency. Molecular docking with an antioxidant target protein (PDB ID: 1HD2) revealed a binding energy of −7.41 kcal mol⁻¹, supporting the experimental results. Real-sample analysis confirmed the practical application of compound 3 in detecting Ni²⁺ ion in environmental water samples. These findings establish compound 3 as a multifunctional platform with promising applications in environmental monitoring and biomedical research.