Frontiers in Chemistry最新文献

[This retracts the article DOI: 10.3389/fchem.2024.1426179.].

Introduction: In the context of sustainable methodologies for wastewater remediation, this study focuses on the development of an efficient and low-cost biosorbent derived from Sardina pilchardus fish scales (SPFS) for dye removal applications. Methods: The prepared biosorbent was characterized using physicochemical and morphological analyses to evaluate its surface properties and porosity. Batch adsorption experiments were conducted to investigate the removal of Methylene Blue (MB) and Congo Red (CR), including kinetic, isotherm, thermodynamic, and regeneration studies. Results: The material exhibited a porous structure and rich surface functional groups favorable for adsorption. Fast adsorption kinetics were observed, with equilibrium reached within 30 min for both dyes. The adsorption process followed the pseudo-second-order model, indicating chemisorption as the controlling mechanism. Isotherm analysis showed that the Langmuir-Freundlich model provided the best fit, suggesting a heterogeneous surface with combined monolayer and multilayer adsorption. Maximum adsorption capacities of 187.634 mg/g for CR and 129.694 mg/g for MB were achieved, placing SPFS among the most efficient bio-derived adsorbents reported. Thermodynamic parameters confirmed that the adsorption processes were spontaneous, exothermic, and favorable. Discussion: Although a slight decrease in adsorption efficiency was observed at higher temperatures, the biosorbent demonstrated excellent regenerability and maintained high performance over multiple cycles. These findings highlight the strong potential of fish-scale-derived biosorbents as sustainable, efficient, and reusable materials for dye removal in wastewater treatment.

Transition metal complexes with sulfur-donor ligands serve as efficient catalysts in numerous homogeneous reactions, owing to the coordination diversity of sulfur-based ligands and the possibility to obtain chiral and achiral complexes. Historically dominated by phosphorus and nitrogen, transition metal compounds with electron-rich sulfur-donor ligands have recently attracted research interest because of their close connection with enzymatic transformation. This review presents a comprehensive overview of recent applications of sulfur-ligated metal complexes in hydrogenative and strictly related hydrogen auto-transfer processes, namely hydrogenation, transfer hydrogenation and borrowing hydrogen reactions. Particular attention is given to the impact of ligand selection on the reaction outcomes, and on the influence of sulfur to give stability at the catalytically active metal complex. Additionally, the review compares conventional hydrogenation and transfer hydrogenation strategies with emerging approaches involving metal-ligand cooperation in the presence of sulfur-based ligands.

Four novel gold(I) N-heterocyclic carbene (NHC) complexes were synthesized and characterized; they are tuned in terms of the aromatic extension of the NHC scaffold and two of them contain a thiosugar residue to enhance their cellular uptake. To verify their potential interaction with human serum albumin (HSA), ESI-MS interaction analysis and fluorescence titrations were performed. Biological studies were carried out to evaluate their possible cytotoxic effect on three ovarian cancer cell lines, i.e., A2780 (both sensitive and cisplatin-resistant), and SKOV-3. Confocal microscopy and fluorescence-activated cell sorting tests were also carried out for the four complexes. Thiosugar conjugation proved to be an effective strategy to enhance potency and selectivity, resulting in a considerable improvement compared to the corresponding complexes lacking the thiosugar moiety. Furthermore, six bioconjugates containing targeting peptides were synthesized; in most cases, no significant improvement in either cytotoxic activity or selectivity was observed, except for the LHRH peptide conjugates, which showed a slight enhancement in both cytotoxicity and selectivity compared to the unconjugated complexes.

Background: Tripterygium wilfordii Hook F (TwHF), a traditional Chinese herb with immunosuppressive activity, has demonstrated clinical efficacy in the treatment of autoimmune diseases. However, the clinical application of TwHF has been greatly limited owing to its toxicity. Previously, we showed that the toxicity of TwHF can be reduced by liquorice processing, but the material basis for this reduced toxicity remains unclear.

Methods: Here, we hypothesized that liquorice processing affects the components of TwHF. And LC-IT-TOF/MS together with plant metabolomics was applied to analyse the chemical composition of raw TwHF (Raw), TwHF combined with liquorice (Com), and TwHF processed by liquorice (Pro).

Results: As a result, three differential compounds in TwHF, including triptolide, celastrol and wilforlide A, were tentatively identified. At the same time, we found that there were nine differential compounds from liquorice, including isoliquiritin, uralenin, coumestrol, liquiritigenin, schaftoside, glycyrrhizic acid, glyyunnanprosapogenin D, uralsaponin B and isolicoflavonol.

Conclusion: These results will provide a basis for the scientific and rational use of TwHF processed by liquorice in the clinic.

Luminescent thermometry has emerged as a powerful tool for remote temperature sensing, yet the development of sustainable materials that combine robust photophysical performance with environmental compatibility remains a challenge. Herein, we report a bio-derived luminescent thermometric film obtained by incorporating the europium-based complex [Eu (tta)₃(PIB)] into a castor-oil-based alkoxysilane polymer (SiCO). The resulting luminescent films are transparent, stable, and preserve the structural integrity and optical characteristics of the trivalent europium (Eu³⁺) complex, as confirmed by spectroscopic analyses. Efficient ligand-to-metal energy transfer gives rise to well-defined Eu³⁺ emission, while residual ligand-centered luminescence enables a ratiometric thermometric approach. Temperature-dependent photoluminescence measurements reveal distinct thermal quenching behaviors of the ligand and Eu³⁺ emissions, allowing reliable temperature readout through an intensity ratio thermometric parameter. The optimized SiCO-0.25Eu film exhibits a maximum relative thermal sensitivity of 1.31% K^-1 at 189 K and a minimum temperature uncertainty of 0.43 K at 173 K, maintaining stable performance over a broad low-temperature range (42-282 K) and under repeated thermal cycling. These results demonstrate that castor-oil-derived polymer matrices can serve as efficient and sustainable platforms for luminescent thermometry, offering a promising route toward environmentally friendly luminescent temperature sensors for low-temperature applications.

Shock waves are ubiquitous in star-forming regions, protoplanetary disks, and cometary environments, yet their role in processing refractory metals remains poorly understood. Here, we show that laboratory shock-tube experiments produce nanophase Fe-Ni alloy from Fe and Ni powders under conditions resembling low-velocity (1-2 km/s) dust-heating shocks in the interstellar medium and cometary comae. The reflected-shock temperature exceeds 6000 K, and pressures reach around 14.5 bar, persisting for about 2-3 ms and completely vapourising the metal powders into an atomic vapour. Subsequent rarefaction drives a catastrophic thermal quench at ∼10⁶ K/s, inducing direct vapour-phase condensation of bcc kamacite (α-Fe-Ni) without an intervening taenite phase. X-ray diffraction and Rietveld refinement confirm a homogeneous kamacite solid solution, while FESEM reveals octagonal to sub-spherical particles consistent with condensation from transient vapour/melt droplets. HRTEM, SAED, and FFT analyses reveal well-ordered bcc lattices and high densities of dislocations and deformation twins, suggesting rapid quench crystallisation under extreme non-equilibrium conditions. HAADF-STEM and EDS mapping show atomic-scale compositional uniformity, with Fe:Ni ratios closely matching the initial composition. The microstructures, compositions, and sizes of these shock-synthesised nanophase Fe-Ni alloy particles closely resemble nanophase metals observed in GEMS-bearing IDPs and Wild 2 samples, aligning with Ni-enriched metal vapour inferred from Fe I and Ni I detections in cometary comae. Our results demonstrate that transient, low-velocity shocks can produce nanophase Fe-Ni metal with meteoritic and cometary characteristics, establishing a strong mechanistic link between metal vapour chemistry, dust reprocessing, and the formation of nanoscale kamacite in primitive solar system and interstellar materials.

Aromatic polymers are known for their thermal stability as well as their good mechanical properties, but most of these polymers are synthesised from fossil resources. Vanillin is one of the few aromatic chemicals that is currently commercially produced from biomass and can be derivatised to make it suitable for polycondensation reactions. In this work a vanillin-derived bio-based diol was synthesised exploiting the potential of more benign reagents to replace toxic dimethylformamide. The resulting monomer was utilised in a series of enzymatic polycondensation reactions with different diesters including dimethyl succinate (DMSu), dimethyl adipate and dimethyl sebacate (DMSe), and the aromatic monomers diethyl terephthalate diethyl isophthalate diethyl pyridine-2,5-dicarboxylate (PD25) and diethyl pyridine-2,4-dicarboxylate (PD24) using a lipase to produce semi-aromatic polyesters. The molecular weight of the resulting polyesters increased as the chain length of the diester decreased, with a number average molecular weight of 21.8 kDa for polyesters achieved based on the dimethyl succinate (using diphenyl ether (DPE) as the organic media). For semi-aromatic diesters, para-substituted monomers yielded higher molecular weight polymers compared to the corresponding meta-substituted structure. Several different green solvents were also investigated to carry out this reaction with anisole that resulted to be a good alternative to diphenyl ether with similar number average molecular weights obtained at certain conditions.