Chemical Papers最新文献

By dint of their excessive toxicity and non-biodegradable characteristics, detection of the nitroanilines that have detrimental impacts on human health and the aquatic environment is a crucial issue. For this aim, the potentiality of the silicon carbide (C₁₂Si₁₂) nanocage toward sensing nitroaniline compounds, including ortho-, meta- and para-nitroaniline (ONA, MNA and PNA, respectively), was accomplished through DFT computations. The electrostatic potential findings corroborated the remarkable ability of the C₁₂Si₁₂ nanocage to sense the ONA, MNA, and PNA molecules via the two substantial nucleophilic sites (i.e., N and O atoms) of the aforementioned molecules in the most favorable configurations. In the light of the energetic affirmations, negative interaction energies were recorded for the investigated complexes with values up to − 37.13 kcal/mol. According to the symmetry-adapted perturbation theory findings, the electrostatic force was remarked as the prevailing contribution within the adsorption process. A closer look at the outcomes of the noncovalent interaction index and the quantum theory of atoms in molecules pointed out the partially covalent nature of the interactions within the studied complexes. The apparent alterations in the molecular orbital distributions and global reactivity descriptors of the studied C₁₂Si₁₂ nanocage after the adsorption of the ONA, MNA, and PNA molecules proclaimed the occurrence of the scouted adsorption process. The obtained thermodynamic parameters declared the spontaneous exothermic characteristics of the interactions within the inspected complexes. The obtained findings divulged that the C₁₂Si₁₂ nanocage could be regarded as a promising candidate for sensing the ONA, MNA, and PNA toxic molecules, which in turn will have a pivotal role in preserving the environment.

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The presence of pharmaceutical pollutants in the environment has detrimental effects on the water system which consequently impacts the aquatic and terrestrial life. These pharmaceutical residues exist in trace amounts which require sensitive sample preparation methods for their detection. In this work, surface imprinting polymerization was utilized to successfully synthesize a magnetic metal–organic framework-molecularly imprinted polymer (Fe₃O₄@MIL-101(Cr)@MIP) for use as a selective sorbent for the isolation of selected antibiotics in aqueous environments based on the ultrasound-assisted dispersive technique. A variety of analytical methods and techniques such as Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and Brunauer–Emmett–Teller were used to characterize the structural and morphological features of the synthesized Fe₃O₄@MIL-101(Cr)@MIP. The synthesized Fe₃O₄@MIL-101(Cr)@MIP was then employed as a selective adsorbent in the ultrasound-assisted dispersive molecularly imprinted solid-phase micro-extraction method developed for the extraction and preconcentration of oxytetracycline and chlortetracycline as model antibiotics in wastewater prior to their analysis with high-performance liquid chromatography–diode array detector. Using a multivariate optimization method, important factors such as sample pH, the mass of the adsorbent, eluent volume and elution time were optimized. The analytical method gave the quantification limits of 0.11 µg L⁻¹ and 0.13 µg L⁻¹ for oxytetracycline and chlortetracycline, respectively. The recoveries obtained for oxytetracycline and chlortetracycline, after spiking wastewater samples ranged from 78 to 99%, with relative standard deviations not exceeding 5%. These findings suggested an acceptable analytical method that could be routinely applied for the determination of these drugs in wastewater.

By employing graphene-2,4,6-tribromoaniline for the regioselective activation of sp³ C–H bonds, the study explores a new catalytic mechanism that facilitates the fixation of NAD⁺ to 1,4-NADH in aqueous media under solar light circumstances. The technique provides a sustainable mechanism for organic transformations by demonstrating the effective manipulation of C–H bonds. In this photoinduced reaction, graphene combined with tribromoaniline acts as a strong catalyst, guaranteeing great selectivity and few byproducts. Biochemical activities depend on the activation of NAD⁺ to 1,4-NADH, and this photocatalytic method offers a more environmentally friendly option than conventional techniques. The promise for creating sustainable, environmentally friendly solutions for intricate organic reactionsespecially in bioorganic chemistry, with uses in energy storage and enzymatic processes, is demonstrated by the combination of solar energy and sophisticated catalysis. This discovery presents intriguing opportunities for further study in biocatalysis and green chemistry.

Cocrystallization of chlorzoxazone (CHZ) with ascorbic acid (ASC), a nutraceutical compound as a coformer, is performed for the solubility enhancement of CHZ. The structural interactions of the CHZ-ASC coordinated complex in all possible orientations are predicted using density function theory (DFT) analysis. A binary phase diagram (BPD) is constructed for the CHZ-ASC system to identify the stoichiometric ratio. The liquid-assisted grinding (LAG) method is used to prepare CHZ-ASC cocrystals. In vitro solubility and dissolution rate studies are assessed at different pH levels. DFT analysis identifies the supramolecular heterosynthon complex formation via hydrogen bonds (bond distance of less than 2 Å) and binding energy (∆E_CHZ-ASC) of CHZ-ASC complexes. BPD confirms a “W” shape for the CHZ-ASC system, indicating the system is favorable for obtaining cocrystals at the stoichiometric ratio of 0.75: 0.25 (CHZ:ASC) reactant mixture. CHZ-ASC(CC) is prepared using LAG method and further analyzed. DSC results indicate a lower melting point, while TGA results reveal distinct mass loss behavior of CHZ-ASC(CC) when compared to CHZ and ASC, suggesting the formation of a new crystalline solid. PXRD results confirm the distinct peak, while FTIR peak shifting is attributed to the hydrogen bond (N–H–O = C) interaction, manifesting the existence of CHZ-ASC(CC). The solubility and dissolution rate of CHZ are improved by 1.3–1.8 times compared to that of the pure CHZ when released from CHZ-ASC (CC) under different pH conditions. The surface modification of CHZ with ASC via cocrystallization is found to be supportive for the solubility enhancement of CHZ.

Aristolochia balansae Franch. is an endemic plant species distributed in northern Vietnam. The bark of A. balansae is used to treat dysentery, urinary retention, and sometimes rheumatism. Our first examination of the presence of aristolochic acids in A. balansae led to the isolation and identification of four aristolochic acids together with β-sitosterol, narcissoside, and glucosyringic acid. Cytotoxic and antioxidative screening discovered the potent cytotoxicity against human cancer cell lines HepG-2 (IC₅₀ 19.21 μg/mL) and MCF-7 (IC₅₀ 19.52 μg/mL) as well as DPPH radical scavenging capacity (SC₅₀ 196.41 μg/mL) of aristolochic acid C (aristolochic acid IIIa). To gain a better knowledge of the mechanisms of action of aristolochic acid C against breast and liver cancer, the compound’s binding to HER2 and GSK-3 protein targets was further analyzed using a molecular docking approach. In the energy minimization models, aristolochic acid C showed a good position in the active site of the HER2 and GSK3β proteins with the lowest binding energy with a ∆G value of − 11.09 kcal/mol and − 8.129 kcal/mol, respectively. A theoretical thermodynamic study was also conducted to examine the radical scavenging mechanism of aristolochic acid C based on DFT calculation. DFT parameters, such as BDE (bond dissociation enthalpy), IP (ionization potential), ETE (electron transfer enthalpy), PDE (proton dissociation enthalpy), and PA (proton affinity), were used to characterize the antioxidative mechanisms of the compound in different environments: gas, water, and pentyl ethanoate. DFT calculation showed that the FHT mechanism was the main antiradical mechanism in the gaseous phase, but the SPLET mechanism may be more favored from a thermodynamic perspective in the water phase. The presence of the C-8 hydroxyl group is requisite for enhancing the antiradical activities of 6- and/or 8-hydroxyl-substituted derivatives of aristolochic acids.

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In this study, composite of Ni₃S₄/NiS₂ was synthesized using single-step hydrothermal route. A series of characterization like X-ray diffraction and Fourier transform infrared confirms the formation of heterostructure nickel sulfide which consists of NiS₂ and Ni₃S₄ phase. Characteristics of mixed phase of Ni₃S₄/NiS₂ relationship have been examined by electrochemical test. Charge transfer resistance of the synthesized composite Ni₃S₄/NiS₂ is 15.79 (Omega). Areal and specific capacitance of prepared composite is 4.96 F/cm² and 545 F/g at 3 mV/s, respectively, and it shows 89% cyclic stability over 1600 cycle at constant scan rate of 50 mV/s. 1 M LiOH aqueous solution used as electrolyte during the characterization of electrochemical test. Surface property of composite Ni₃S₄/NiS₂ has been examined by nitrogen isotherm, and pore size of the composite is 3.934 nm which provides the effective path for electron transportation between the surface of working electrode and electrolyte. The calculated parameters of the series of characterization indicated that prepared composite of Ni₃S₄/NiS₂ is a potential electrode material for electrochemical devices.

This study explores the potential of agricultural waste, specifically gingelly biomass from three varieties—Nirmala, Smarak, and Prachi—for biofuel production, a topic that remains largely unexamined. To assess the feasibility of using this biomass as a biofuel feedstock, various characterization techniques were employed, including thermogravimetric analysis/differential thermal analysis (TG/DTA), Fourier transform infrared spectroscopy (FTIR), CHNS/O analysis, and inductively coupled plasma optical emission spectroscopy (ICP-OES). The results revealed an average cellulose content of 35.75%, volatile matter at 76.46%, and a calorific value of 17.40 MJ/kg, indicating the potential of gingelly biomass for a range of industrial applications. Notably, the activation energy (Eα) was observed to be lower for the Smarak variety (approximately 172 kJ/mol) compared to Nirmala (approximately 185 kJ/mol) and Prachi (approximately 179 kJ/mol). The minor difference of 3–4 kJ/mol between Aα and Hα indicates the viability of the thermal disintegration process for this biomass. The master plot illustrates the intersection of experimental and theoretical curves, reflecting the intricate nature of the thermal disintegration process. Additionally, in the sesame variety Nirmala, all the cellulose synthase-specific gene primers were expressed in form of producing distinct bands of varying lengths. High ethanol yield of 0.40 g/g was recorded for Nirmala variety, indicating it as a better candidate for bioethanol production. This study demonstrates the first comprehensive link between kinetic thermodynamic modelling, molecular profiling, and ethanol fermentation efficiency in gingelly biomass, providing new benchmarks for integrated biofuel feedstock evaluation. The results highlight the unique biofuel potential of sesame biomass, which has remained underexplored till date.

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This study investigates the stability and potential of lead-free double oxide perovskites Li₂MoZO₆ (Z = Si, Ge, and Sn) for solar energy harvesting. Density functional theory (DFT) calculations using the WIEN2k package reveal that all three compounds exhibit cubic symmetry (space group Fm-3m). Additionally, tolerance factor analysis, phonon spectra, formation energy calculations, and ab initio molecular dynamics simulation verified the structural, dynamic, thermodynamic, and thermal stability of the compounds at room temperature. Electronic properties calculated using the TB-mBJ and HSE06 potentials reveal that Li₂MoZO₆ (Z = Si, Ge, Sn) compounds exhibit semiconducting behavior, with band gaps of (1.78, 1.64, and 1.34) eV, respectively, from TB-mBJ calculations, and corresponding values of approximately (2.10, 1.85, and 1.64) eV from HSE06 calculations. Elastic constants calculations demonstrate the mechanical stability, ductility, and anisotropy of the given compounds. The analysis of optical properties reveals high absorption coefficients and significant optical conductivity within the visible and near-UV spectrum, indicating the potential applications of the simulated compounds in photovoltaic and optoelectronic.

Heterojunctions comprising wide and narrow gap materials with distinct band edge potentials always remain an ideal choice to operate under wide spectrum of solar light for the photocatalytic reactions. In this context, integrating ZnO and g-C₃N₄ gains prominent interest from the prospect of easy preparation and suitable band edge positions to form the heterojunctions. In the current work, the ZnO/g-C₃N₄ is obtained by annealing the pre-crystallized materials (550 °C) and characterized by using various analytical techniques. The X-ray diffraction results confirmed the composite formation, while the optical response measurements revealed the light absorption ability in the visible region. The ZnO/g-C₃N₄ enabled the faster degradation of indigo carmine dye compared to individual phase counterparts under the light illuminated conditions. This was attributed to the formation of S-scheme heterojunction which allowed energetic charge carriers to participate in the reactions and was later supported with radical scavenging experiments. Furthermore, the density functional theory calculations indicated the formation of interfacial bonds such as Zn–N and Zn–C which played a vital role in boosting the charge carrier separation process.