Molecules

11 pages, 1428 KB

Open AccessArticle

Design of a Novel Class of N-Heterocyclic Carbene Cycloplatinated Complexes Containing Pyrene Chromophores

by Zeping Zhang, Yaping Cheng, Geoffrey Gontard, Tim Riesebeck, Sandy Fornal, Thomas Strassner and Hani Amouri

Molecules 2025, 30(22), 4473; https://doi.org/10.3390/molecules30224473 (registering DOI) - 19 Nov 2025

Abstract

Cycloplatinated complexes incorporating pyrene chromophores of the formulae (C^C*)Pt(acac) (3, 4), (C^C* = Pyrenyl-NHC, acac = acetylacetonate) were prepared and fully characterized. For comparison, two regioisomeric complexes were prepared following synthetic procedures developed by us. One isomer has the Pt(II) [...] Read more.

Cycloplatinated complexes incorporating pyrene chromophores of the formulae (C^C*)Pt(acac) (3, 4), (C^C* = Pyrenyl-NHC, acac = acetylacetonate) were prepared and fully characterized. For comparison, two regioisomeric complexes were prepared following synthetic procedures developed by us. One isomer has the Pt(II) center attached to the 2-position of the pyrene chromophore, while the other regioisomer has the metal center attached at the 1-position of the organic chromophore. The molecular structures of 3 and 4 were ascertained by X-ray diffraction, and they prove the identity of the targeted compounds. Both complexes are emissive at room temperature in the red part of the spectrum in poly(methyl methacrylate) (PMMA), as well as at 77 K in 2-methyltetrahydrofuran (2-MeTHF). The regioisomer containing the Pt(II) at the 1-position shows enhanced emissive properties compared to the other regioisomer. Full article

(This article belongs to the Special Issue Inorganic Chemistry in Europe 2025)

► Show Figures

Graphical abstract

15 pages, 2211 KB

Open AccessArticle

Structural and Spectroscopic Study of Benzoperimidines Derived from 1-Aminoanthraquinone and Their Application to Bioimaging

by Elena Kirilova, Armands Maļeckis, Muza Kirjušina, Ligita Mežaraupe, Ilze Rubeniņa, Aija Brakovska, Veronika Pavlova, Sanita Kecko, Inta Umbraško, Vladimir Kiyan, Lyudmila Lider, Aleksandrs Pučkins and Sergey Belyakov

Molecules 2025, 30(22), 4472; https://doi.org/10.3390/molecules30224472 (registering DOI) - 19 Nov 2025

Abstract

In this research, we studied the synthesis and characterization of a novel amidine derivative of benzoperimidine derived from 1-aminoanthraquinone, focusing on its emission properties and potential applications in confocal laser scanning microscopy. The synthesized compound exhibited pronounced solvatochromic behavior in various solvents. Spectroscopic [...] Read more.

In this research, we studied the synthesis and characterization of a novel amidine derivative of benzoperimidine derived from 1-aminoanthraquinone, focusing on its emission properties and potential applications in confocal laser scanning microscopy. The synthesized compound exhibited pronounced solvatochromic behavior in various solvents. Spectroscopic analysis, including ¹H-, ¹³C-, and mass spectrometry, confirmed the chemical structure. The structure of three compounds was also determined using X-ray diffraction analysis; this study revealed the structural features of these substances in the solid state. The compound’s antimicrobial activity was evaluated using the agar diffusion method with the bacterium Bacillus subtilis subsp. Spizizenii. Furthermore, the study introduces a dye designed for imaging of the parasitic flatworm Opisthorchis felineus, demonstrating its potential in visualizing biological specimens. Full article

(This article belongs to the Special Issue Heterocycles: Design, Synthesis and Biological Evaluation, 4th Edition)

► Show Figures

Figure 1

42 pages, 1294 KB

Open AccessReview

Green and Emerging Microextraction Strategies for Bioanalytical Determination of Hormones: Trends, Challenges, and Applications

by David Vicente-Zurdo, Sonia Morante-Zarcero and Isabel Sierra

Molecules 2025, 30(22), 4471; https://doi.org/10.3390/molecules30224471 - 19 Nov 2025

Abstract

Accurate and sensitive determination of hormones in biological matrices is essential for clinical diagnostics, therapeutic monitoring, and endocrine research. However, hormone determination presents significant challenges due to their typically low concentrations, complex sample matrices, and structural diversity. In recent years, microextraction techniques have [...] Read more.

Accurate and sensitive determination of hormones in biological matrices is essential for clinical diagnostics, therapeutic monitoring, and endocrine research. However, hormone determination presents significant challenges due to their typically low concentrations, complex sample matrices, and structural diversity. In recent years, microextraction techniques have emerged as strategic tools in bioanalytical chemistry, offering advantages in terms of miniaturization, enhanced selectivity, and compatibility with the principles of green analytical chemistry (GAC). This review provides a comprehensive overview of green and emerging microextraction approaches for the determination of steroidal, thyroid, peptide, and other hormones in biological samples. Key techniques such as solid-phase microextraction (SPME) and dispersive liquid–liquid microextraction (DLLME), followed by high-performance liquid chromatography (HPLC) coupled to diode array detectors (DADs) or mass spectrometry (MS), are critically discussed. Special emphasis is placed on the use of environmentally friendly solvents, such as deep eutectic solvents (DESs), supramolecular solvents (SUPRASs), and advanced sorbents including molecularly imprinted polymers (MIPs) and nanostructured magnetic phases. Applications across various bioanalytical matrices (urine, plasma, serum, saliva, tissues…) are examined in terms of sensitivity, selectivity, and validation parameters. Finally, current challenges, method development gaps, and future directions are highlighted to support the continued advancement of sustainable hormone determination in complex biological systems. Full article

(This article belongs to the Special Issue Emerging Trends in Microextraction Techniques for Bioanalytical Applications)

28 pages, 5434 KB

Open AccessArticle

Comprehensive Chemical Composition Evaluation of Ziziphus jujuba var. spinosa Germplasm Resources and Selection of Elite Cultivars for Seed, Pulp, and Leaf Utilization

by Xiaochen Song, Yongqing Zhang and Longfei Zhang

Molecules 2025, 30(22), 4470; https://doi.org/10.3390/molecules30224470 - 19 Nov 2025

Abstract

Background: Ziziphus jujuba Mill. var. spinosa (Bunge) Hu ex H. F. Chow. (ZS) is a valuable plant with diverse economic applications, as all its organs contain bioactive secondary metabolites. The seeds, known as Suanzaoren in traditional Chinese medicine, are utilized as both [...] Read more.

Background: Ziziphus jujuba Mill. var. spinosa (Bunge) Hu ex H. F. Chow. (ZS) is a valuable plant with diverse economic applications, as all its organs contain bioactive secondary metabolites. The seeds, known as Suanzaoren in traditional Chinese medicine, are utilized as both a medicinal and edible resource, while the fruit pulp and leaves serve as significant raw materials in the food industry. Increasing market demand for Suanzaoren has led to expanded cultivation, though current production practices emphasize seed utilization, resulting in the underutilization of pulp and leaf tissues. In agricultural systems, developing elite varieties is an effective strategy for enhancing crop yield and quality. Breeding initiatives should establish specific objectives aligned with particular end uses, such as seed, pulp, or leaf production. Germplasm serves as the foundational material for breeding programs, so its selection must correspond to intended applications. Evaluating existing germplasm resources based on chemical composition profiles will provide a basis for developing improved ZS varieties. Objective: This study aimed to systematically compare the characteristic chemical composition in the seeds, pulp, and leaves of ZS. By quantifying key chemical components—such as flavonoid glycosides and saponins in seeds, organic acids and phenolic compounds in pulp, and flavonol glycosides and phenolic acids in leaves—we evaluated the quality of ZS germplasm resources. The resulting compositional profiles provide a concrete basis for selecting and breeding elite cultivars tailored to specific end uses, including seed, pulp, or leaf production. Methods: Chemical characterization was performed using ultra-high-performance liquid chromatography coupled with hybrid quadrupole-orbitrap mass spectrometry (UPLC-Q-Exactive Orbitrap MS/MS). Quantitative analysis of chemical composition was conducted using high-performance liquid chromatography with evaporative light scattering detection (HPLC-ELSD). Multivariate statistical analyses—including principal component analysis (PCA), orthogonal partial least squares discriminant analysis (OPLS-DA), and entropy-weighted technique for order preference by similarity to an ideal solution (entropy-weighted TOPSIS)(EWT)—were employed for comprehensive data evaluation. Results: A comprehensive phytochemical analysis of Ziziphi spinosae (ZS) was conducted, identifying 144 distinct compounds across the seeds, pulp, and leaves. Of these, 114 were found in the seeds, 84 in the leaves, and 79 in the pulp. The seeds were particularly rich in flavonoid glycosides, such as spinosin and 6′′′-feruloylspinosin, as well as saponins like jujuboside A and B. The pulp was dominated by organic acids, including citric acid, and phenolic compounds, while the leaves were abundant in flavonol glycosides, including rutin, and phenolic acids such as isochlorogenic acid B. Based on the chemical composition profiles, the ZS germplasms were evaluated for specific applications. ZS24, ZS22, and ZS3 were identified as the most suitable for seed production, ZS3, ZS6, and ZS9 for pulp utilization, and ZS20, ZS3, and ZS18 for leaf-based applications. With respect to the integrated utilization of multiple plant parts(roots, stems, and leaves), ZS6, ZS3, and ZS24 demonstrated the highest potential. Conclusions: The identification of superior germplasm resources provides strategic direction for the breeding of elite ZS cultivars. These findings will enable the comprehensive utilization of ZS plant resources and support the high-quality development of related industries. Full article

23 pages, 2137 KB

Open AccessArticle

Sol–Gel Synthesis of NiO-Fe₂O₃-SiO₂/Al₂O₃ Catalysts with Statistical and AI-Based Analysis of Experimental Results

by Aleksandr A. Buzaev, Valerya A. Tkachuk, Konstantin S. Ushenin, Daria N. Staritsyna, Sofya V. Gandybina, Alexandra M. Zakharkiva, Darina K. Ivanova, Ekaterina S. Lyutova, Mariya P. Shcherbakova-Sandu, Irina A. Kurzina and Lyudmila P. Borilo

Molecules 2025, 30(22), 4469; https://doi.org/10.3390/molecules30224469 - 19 Nov 2025

Abstract

The development of efficient and cost-effective catalysts is crucial for modern catalytic processes, especially in oxidation reactions. In this study, a sol–gel method was successfully adapted for the synthesis of NiO-Fe₂O₃-SiO₂/Al₂O₃ catalysts. The optimized [...] Read more.

The development of efficient and cost-effective catalysts is crucial for modern catalytic processes, especially in oxidation reactions. In this study, a sol–gel method was successfully adapted for the synthesis of NiO-Fe₂O₃-SiO₂/Al₂O₃ catalysts. The optimized sol–gel process incorporates precise heat treatment control, enabling the production of catalysts with a particle size of 44 nm and a specific surface area of 134.79 m²/g. Extensive characterization revealed several significant advantages: a decrease in the heat treatment temperature to 400 °C, maintaining high material dispersion, and eliminating expensive modifiers. Critical synthesis parameters were identified: the Ni/Fe ratio and the heating rate of the heat treatment. Catalytic activity was demonstrated in a model reaction of decane oxidation. Experimental results were confirmed by statistical analysis, and large language models further assisted in the mechanistic interpretation of the results. Full article

(This article belongs to the Section Materials Chemistry)

► Show Figures

Graphical abstract

25 pages, 1806 KB

Open AccessArticle

Study on the Isolated Asphaltene Thermal Cracking from an Unconventional Oil Using Diverse Estimating Arrhenius Parameter Approaches

by Guillermo Félix, Alexis Tirado, Mikhail A. Varfolomeev, Eder Lugo-Medina, Carlos A. Soto-Robles and Jorge Ancheyta

Molecules 2025, 30(22), 4468; https://doi.org/10.3390/molecules30224468 - 19 Nov 2025

Abstract

The lack of complex schemes and proper kinetic studies for asphaltenes pyrolysis is a significant problem for understanding the reaction mechanisms. Therefore, this study evaluates various parameter estimation approaches (focusing on reaction rate coefficients and Arrhenius parameters), objective functions (sum of squared errors [...] Read more.

The lack of complex schemes and proper kinetic studies for asphaltenes pyrolysis is a significant problem for understanding the reaction mechanisms. Therefore, this study evaluates various parameter estimation approaches (focusing on reaction rate coefficients and Arrhenius parameters), objective functions (sum of squared errors and average absolute errors), and reaction schemes (4-lump and 6-lump) for kinetic modeling of asphaltene pyrolysis. The reaction schemes include asphaltenes, maltenes, gases, and coke, as well as the fractionation of maltenes into polar aromatics, naphthene aromatics, and saturates. Both networks showed adequate accuracy, but the 6-lump model improves yield predictions. Using Method 1 (optimizing reaction rate coefficients) and the sum of square errors as the objective function yields the best accuracy. The analyses confirm that temperature influences selectivity: lower temperatures (below 390 °C) favor the generation of maltenes and gases, while higher temperatures (above 390 °C) promote coke formation. Extended high-temperature exposure leads to secondary cracking of maltenes. Furthermore, the key transformations include the cleavage of aliphatic chains, the aromatization of saturated aromatics, and the polyaddition of free radicals. Full article

(This article belongs to the Special Issue Chemistry Applied to Enhanced Oil Recovery)

25 pages, 2776 KB

Open AccessArticle

Effective Antioxidants as Plausible Ligands in Chromium(III) Supplementation: How Complexation Modulates Catechol-Based Polyphenols

by Hanna Lewandowska, Zhe Chen, Krystian Marszałek, Włodzimierz Lewandowski and Renata Świsłocka

Molecules 2025, 30(22), 4467; https://doi.org/10.3390/molecules30224467 - 19 Nov 2025

Abstract

This study examines the impact of metal coordination on the antioxidant and pro-oxidant properties of 3,4-dihydroxybenzoic acid (3,4-DHBA) and caffeic acid (CA). Their Na(I), K(I) salts and Cr(III) complexes were evaluated in vitro using radical scavenging assays (ABTS, DPPH, hydroxyl, and superoxide), ferric- [...] Read more.

This study examines the impact of metal coordination on the antioxidant and pro-oxidant properties of 3,4-dihydroxybenzoic acid (3,4-DHBA) and caffeic acid (CA). Their Na(I), K(I) salts and Cr(III) complexes were evaluated in vitro using radical scavenging assays (ABTS, DPPH, hydroxyl, and superoxide), ferric- and cupric-reducing power, and inhibition of linoleic acid peroxidation. Alkali metal coordination generally decreased radical scavenging activity, though K complexes and Cr–3,4-DHBA improved lipid peroxidation inhibition. Cr(III) chelation produced ligand-dependent effects: it markedly increased the reducing power of CA while reducing that of 3,4-DHBA and uniquely promoted pro-oxidant behavior in CA under superoxide conditions. These outcomes reflect how chromium chelation alters electronic distribution and charge transfer, enhancing reducing power in single-electron transfer assays while enabling redox cycling in radical scavenging systems, underscoring its dual and ligand-dependent biological significance. Full article

(This article belongs to the Special Issue The Impact of Metal Complexes with Active Small Molecules in Biological Systems)

► Show Figures

Graphical abstract

18 pages, 5188 KB

Open AccessArticle

On the Role of MoSe₂ in Promoting Persulfate Activation by Fe-Based Catalysts: Dual Redox Cycles and Performance and Mechanism of Efficient Phenol Degradation in Water

by Yirong Ren, Hao Zhao, Zerui Lu and Zuoyan Chen

Molecules 2025, 30(22), 4466; https://doi.org/10.3390/molecules30224466 - 19 Nov 2025

Abstract

The recalcitrance and biological toxicity of phenolic pollutants pose a serious threat to the safety of aquatic environments, and developing efficient and stable catalytic degradation technologies is a key research focus in the current environmental field. In this study, a composite material (MSN) [...] Read more.

The recalcitrance and biological toxicity of phenolic pollutants pose a serious threat to the safety of aquatic environments, and developing efficient and stable catalytic degradation technologies is a key research focus in the current environmental field. In this study, a composite material (MSN) of NH₂-MIL-101(Fe) modified by MoSe₂ nanosheets was constructed via a one-step composite strategy, aiming to address the bottlenecks of low Fe³⁺/Fe²⁺ cycling efficiency and iron ion leaching in traditional Fe-based MOFs when activating peroxymonosulfate (PMS). Characterization results showed that MoSe₂ nanosheets were uniformly dispersed on the surface of NH₂-MIL-101(Fe), and strong electronic interactions existed between them, which significantly optimized the electronic environment of active sites. MSN-3 exhibited excellent performance in activating PMS for phenol degradation: the degradation rate reached 90% within 30 min, with a k = 0.073 min⁻¹, which was much higher than that of other systems. It also showed good structural stability and cyclic regeneration ability. Mechanistic studies confirmed that the core active species in the MSN-3/PMS system are ¹O₂, •SO₄⁻ and •OH. The two-dimensional layered structure of MoSe₂ can serve as an efficient electron transport bridge to promote Fe³⁺/Fe²⁺ cycling; amino modification further optimizes the electron density of Fe active centers. The two synergistically construct a dual redox cycle of Fe³⁺/Fe²⁺ and Mo⁴⁺/Mo⁶⁺, significantly enhancing PMS activation efficiency and ¹O₂ production. This study provides a new strategy for designing Fe-MOFs-based PMS activation catalysts and also offers technical support for the practical treatment of recalcitrant organic pollutants in water. Full article

► Show Figures

Figure 1

30 pages, 6871 KB

Open AccessArticle

Robust All-Solid-State Batteries with Sodium Ion Electrolyte, Aluminum and Additive Manufacturing Inconel 625 Electrodes

by Manuela C. Baptista, Antonio B. Vale, Jose M. Costa and Maria Helena Braga

Molecules 2025, 30(22), 4465; https://doi.org/10.3390/molecules30224465 - 19 Nov 2025

Abstract

This study investigates all-solid-state batteries employing multifunctional metallic current collectors/electrodes that remain electrochemically inert toward an alkali-based Na ion solid electrolyte. Inconel 625 was evaluated as the positive current collector in combination with aluminum as the negative electrode and the ferroelectric electrolyte Na2.99Ba0.005OCl. [...] Read more.

This study investigates all-solid-state batteries employing multifunctional metallic current collectors/electrodes that remain electrochemically inert toward an alkali-based Na ion solid electrolyte. Inconel 625 was evaluated as the positive current collector in combination with aluminum as the negative electrode and the ferroelectric electrolyte Na2.99Ba0.005OCl. The inertness of both electrodes enabled the construction of a robust device architecture that behaved as a true battery, exhibiting a two-phase equilibrium discharge plateau at ~1.1 V despite the absence of traditional Faradaic reactions. After a one-month rest period, the cell was sequentially discharged through external resistors and retained full functionality for one year. Cyclic voltammetry confirmed a stable electrochemical response over repeated cycling. The final long-term discharge under a 9.47 kΩ load produced a steady ~0.92 V plateau and delivered a total capacity of 35 mAh (~2.3 mAh·cm⁻²). Post-mortem analyses revealed excellent chemical and mechanical stability of Inconel 625 after extended operation, while aluminum showed superficial surface degradation attributed to residual moisture, with X-ray diffraction indicating the formation of aluminum hydroxide. Scanning Kelvin probe measurements guided electrode selection and provided insight into interfacial energetics, whereas scanning electron microscopy confirmed interface integrity. Complementary density functional theory simulations optimized the crystalline bulk and surfaces of Inconel, demonstrating interfacial stability at the atomic scale. Overall, this work elucidates the fundamental driving forces underlying traditional battery operation by studying a “capacity-less” system, highlighting the central role of interfacial electrostatics in sustaining battery-like discharge behavior in the absence of redox-active electrodes. Full article

(This article belongs to the Special Issue Advanced Electrode Materials and Interfaces for Next-Generation Solid-State Batteries)

► Show Figures

Figure 1

18 pages, 3358 KB

Open AccessArticle

Green Synthesis of Silica Nanoparticles from Sugarcane Bagasse Ash for Stable Pickering Oil-in-Water Emulsions

by Daniel Jaramillo-Vélez, Mariana Ochoa-Castaño, Andrea Flórez-Caro, Luis David Botero, Esteban Ureña-Benavides, Raúl Adolfo Valencia-Cardona, Jorge Andrés Velásquez-Cock and Catalina Gómez-Hoyos

Molecules 2025, 30(22), 4464; https://doi.org/10.3390/molecules30224464 - 19 Nov 2025

Abstract

The present study explores novel alternatives for the exploitation of sugarcane bagasse ash by obtaining and modifying SiO₂ nanoparticles through a green synthesis method. The hydrophilic nature of the nanoparticles was modified using oleic acid. The nanoparticles were characterized using FTIR, FESEM, [...] Read more.

The present study explores novel alternatives for the exploitation of sugarcane bagasse ash by obtaining and modifying SiO₂ nanoparticles through a green synthesis method. The hydrophilic nature of the nanoparticles was modified using oleic acid. The nanoparticles were characterized using FTIR, FESEM, and DLS, and their performance in the stabilization of Pickering emulsions was also studied. FESEM micrographs of the nanoparticles revealed an irregular and agglomerated structure. EDS confirmed that their main components are oxygen and silicon, and ATR-FTIR spectra demonstrated that oleic acid effectively modified the nanoparticles. Subsequently, O/W Pickering emulsions were fabricated by combining rotor–stator homogenization and probe ultra-sonication, using dodecane and liquid paraffin as model oil phases and SiO₂ NPs as stabilizers. Static light scattering measurements showed that the emulsions exhibited polydispersity, while photographic monitoring confirmed that their physical stability was affected by the concentrations of oleic acid and nanoparticles: concentrations of up to 20.0 wt% and 1.0 wt%, respectively, produced emulsions that remained stable for 7 to 15 days. This study identifies the behavior and challenges associated with novel pathways for the valorization of sugarcane bagasse ash. The stabilization of Pickering emulsions using the obtained SiO₂ NPs highlights their potential in pharmaceutical, cosmetic, and food applications. Full article

(This article belongs to the Special Issue Bioactive Compounds in Plants: Extraction and Application)

► Show Figures

Figure 1

16 pages, 2043 KB

Open AccessArticle

Paramagnetic Agents for SE DNP: Synthesis and ESR Characterization of New Lipophilic Derivatives of Finland Trityl

by Victor M. Tormyshev, Danil A. Kuznetsov, Arthur E. Raizvikh, Olga Yu. Rogozhnikova, Tatiana I. Troitskaya and Elena G. Bagryanskaya

Molecules 2025, 30(22), 4463; https://doi.org/10.3390/molecules30224463 - 19 Nov 2025

Abstract

Triarylmethyl radicals (TAMs) have recently emerged as highly effective polarizing agents in dynamic nuclear polarization (DNP) under viscous conditions, enabling substantial hyperpolarization via the solid-effect (SE) DNP mechanism even at room temperature. A comparable, though less pronounced, enhancement was observed for BDPA radicals [...] Read more.

Triarylmethyl radicals (TAMs) have recently emerged as highly effective polarizing agents in dynamic nuclear polarization (DNP) under viscous conditions, enabling substantial hyperpolarization via the solid-effect (SE) DNP mechanism even at room temperature. A comparable, though less pronounced, enhancement was observed for BDPA radicals embedded in phosphocholine-based lipid bilayers. Given the increasing interest in elucidating the structure and dynamics of biopolymers and their high-molecular-weight assemblies—such as cell membranes—this study focuses on the design, synthesis, and characterization of paramagnetic agents tailored for DNP-based structural biology. To this end, we synthesized a series of TAM derivatives functionalized with lipophilic substituents and characterized their magnetic resonance properties, including isotropic hyperfine interaction (HFI) constants on carbon nuclei and electron spin relaxation times (T₁ and T_m) at low temperatures (80 K). Echo-detected EPR spectra and electron spin echo envelope modulations (ESEEM) were recorded for novel TAM incorporated into liposomes composed of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC). These low-temperature measurements revealed that the radicals are localized either at the liposome surface or within the lipid bilayer, ensuring optimal accessibility to water molecules. Crucially, the presence of a single cholesterol moiety provides strong noncovalent anchoring within the hydrophobic core of the bilayer. Guided by these findings, we identify an amphiphilic TAM bearing a single cholesterol group and polar carboxyl functionalities as a highly promising candidate for DNP applications in membrane biology, combining efficient polarization transfer, bilayer integration, and aqueous accessibility. Full article

(This article belongs to the Section Physical Chemistry)

► Show Figures

Graphical abstract

11 pages, 1145 KB

Open AccessArticle

Co(II)-Catalyzed Picolinamide-Directed C(sp³)-S Bond Formation with N-(phenylsulfanyl)succinimides

by Jinjing Qin, Shaodong Zhou, Jinwen Luo, Guodong Wang and Kai Wang

Molecules 2025, 30(22), 4462; https://doi.org/10.3390/molecules30224462 - 19 Nov 2025

Abstract

Herein, we disclose a novel and efficient cobalt-catalyzed cross-coupling strategy for picolinamide-directed direct C(sp³)-H bond formation with N-(phenylsulfanyl)succinimides. This method enables the direct construction of C(sp³)–S bonds under mild conditions and exhibits excellent functional group tolerance along with [...] Read more.

Herein, we disclose a novel and efficient cobalt-catalyzed cross-coupling strategy for picolinamide-directed direct C(sp³)-H bond formation with N-(phenylsulfanyl)succinimides. This method enables the direct construction of C(sp³)–S bonds under mild conditions and exhibits excellent functional group tolerance along with a broad substrate scope. Notably, the catalytic system achieves oxidative C–H functionalization without relying on costly or environmentally detrimental oxidants, offering a more sustainable and practical alternative for C–S bond formation. Full article

► Show Figures

Graphical abstract

17 pages, 1370 KB

Open AccessReview

Microplastic Formation and Surface Crack Patterns: A Method for Waste Plastic Identification

by Hisayuki Nakatani and Anh Thi Ngoc Dao

Molecules 2025, 30(22), 4461; https://doi.org/10.3390/molecules30224461 - 19 Nov 2025

Abstract

Accumulation of plastic debris in marine environments has become a critical global issue, with microplastics (MPs) posing persistent ecological risks. This review synthesizes current knowledge on the formation mechanisms of MPs from polyolefins such as polypropylene (PP) and polyethylene (PE), emphasizing the influence [...] Read more.

Accumulation of plastic debris in marine environments has become a critical global issue, with microplastics (MPs) posing persistent ecological risks. This review synthesizes current knowledge on the formation mechanisms of MPs from polyolefins such as polypropylene (PP) and polyethylene (PE), emphasizing the influence of marine conditions on degradation pathways. Autoxidation is identified as the dominant mechanism; however, salinity and chloride ions significantly retard radical formation, altering photodegradation kinetics and crack propagation. These effects lead to distinctive surface morphologies—such as rectangular and trapezoidal crack patterns in PP—which can serve as reliable indicators for polymer identification. This review further explores the role of polymer chain orientation and spherulite structures in crack development and discusses how these features can be leveraged for cost-effective sorting and recycling strategies. Finally, emerging approaches using AI-based image recognition for automated identification of weathered plastics are highlighted as promising tools to enhance resource recovery and mitigate marine plastic pollution. Full article

(This article belongs to the Special Issue 10th Anniversary of Green Chemistry Section)

► Show Figures

Figure 1

24 pages, 1919 KB

Open AccessReview

Immunomodulatory Role of Propolis in Hypoxia and in the Tumor Microenvironment

by Małgorzata Kłósek, Anna Kurek-Górecka, Radosław Balwierz, Katarzyna Góralczyk-Bałys, Michał Górecki and Zenon P. Czuba

Molecules 2025, 30(22), 4460; https://doi.org/10.3390/molecules30224460 - 19 Nov 2025

Abstract

Propolis is a well-known sticky, resinous substance collected by honeybees (Apis mellifera) from the buds of trees and other plants, then mixed with beeswax and their own glandular secretions. Its chemical composition varies widely depending on the bee species, geographic location, [...] Read more.

Propolis is a well-known sticky, resinous substance collected by honeybees (Apis mellifera) from the buds of trees and other plants, then mixed with beeswax and their own glandular secretions. Its chemical composition varies widely depending on the bee species, geographic location, plant sources, and weather conditions. The therapeutic potential of propolis—including antimicrobial, anti-inflammatory, and anticancer effects—has been recognized since antiquity. Cancer remains one of the leading causes of morbidity and mortality worldwide. High levels of hypoxia within tumor tissue significantly contribute to cancer progression and increase the resistance of tumor cells to radio- and chemotherapy. In the tumor microenvironment, cytokines play key roles in processes such as invasion, metastasis, and immune suppression. The concept of the “cytokine field” describes how elevated cytokine levels within the tumor microenvironment create a field effect, influencing surrounding cells. Current research is exploring the use of natural immunomodulators, such as propolis, in combination with conventional chemotherapeutic agents for cancer treatment. This review summarizes the potential immunomodulatory role of propolis within the tumor microenvironment. Full article

(This article belongs to the Special Issue Anti-Inflammatory and Antimicrobial Compounds and Extracts from Plant Sources)

► Show Figures

Figure 1

17 pages, 2508 KB

Open AccessArticle

Preparation and Characterization of Brassica rapa L. Polysaccharide–Zein Nanoparticle Delivery System Loaded with Capsaicin

by Mi Yuan, Lele Chen, Hamulati Hasimu, Mengying Hu and Xiaojun Yang

Molecules 2025, 30(22), 4459; https://doi.org/10.3390/molecules30224459 - 19 Nov 2025

Abstract

Capsaicin, a natural bioactive compound, has attracted wide interest for its potential health benefits. However, its rapid metabolism and strong irritancy upon oral administration have greatly limited its further application. To address these issues, this study developed a nanoparticle delivery system using corn [...] Read more.

Capsaicin, a natural bioactive compound, has attracted wide interest for its potential health benefits. However, its rapid metabolism and strong irritancy upon oral administration have greatly limited its further application. To address these issues, this study developed a nanoparticle delivery system using corn Zein and Brassica rapa L. polysaccharide (BP) as carriers, with capsaicin (CAP) as the core. The optimized formulation (BP:Zein = 1:2, Zein:CAP = 2.5:1, mg/mg) produced stable, uniform spherical nanoparticles with an average particle size of 203.05 nm, a polydispersity index (PDI) of 0.138, a zeta potential of −44.9 mV, an encapsulation efficiency of 54.03%, and a drug loading capacity of 184.57 μg/mg. Fourier transform infrared spectroscopy (FTIR), fluorescence spectroscopy (FS), X-Ray diffraction, scanning electron microscope (SEM), and transmission electron microscopy (TEM) analyses confirmed that CAP was successfully encapsulated, forming nanoparticles through hydrogen bonding and hydrophobic interactions between CAP and Zein. The obtained nanoparticles displayed regular spherical morphology and uniform size distribution. Compared with single-layer Zein–CAP nanoparticles, BP–Zein–Capsaicin (BZC) nanoparticles exhibited markedly improved stability under different pH, ionic strength, and storage conditions. In vitro simulated digestion showed a sustained-release profile, with 36.76% of CAP released after 4 h. The anti-inflammatory experiment showed that both the nanoparticle and free capsaicin groups significantly inhibited xylene-induced acute ear edema in mice, with the medium- and high-dose nanoparticle groups exhibiting stronger anti-inflammatory effects than the free capsaicin group. These findings suggest that the nanoparticle delivery system effectively enhances the anti-inflammatory activity of capsaicin, possibly by improving its stability, achieving sustained release, and enhancing its bioavailability in vivo. Overall, capsaicin-loaded Brassica rapa L. polysaccharide–Zein nanoparticles combine small particle size, high drug loading, and excellent stability, providing a promising strategy for functional food development and targeted bioactive delivery. Full article

► Show Figures

Figure 1

14 pages, 954 KB

Open AccessArticle

Solid Phase Extraction and Determination of Tetracycline Using Gold Nanoparticles Stabilized in a Polymethacrylate Matrix

by Nadezhda V. Saranchina, Daria E. Kuznetsova, Nataliya A. Gavrilenko and Mikhail A. Gavrilenko

Molecules 2025, 30(22), 4458; https://doi.org/10.3390/molecules30224458 - 19 Nov 2025

Abstract

A polymethacrylate matrix (PMM) is proposed for the solid-phase extraction and determination of tetracycline (TC). The study of the influence of medium acidity, temperature, and contact time on the extraction of tetracycline by PMM showed that tetracycline is extracted by the matrix in [...] Read more.

A polymethacrylate matrix (PMM) is proposed for the solid-phase extraction and determination of tetracycline (TC). The study of the influence of medium acidity, temperature, and contact time on the extraction of tetracycline by PMM showed that tetracycline is extracted by the matrix in the form of a singly charged anion H₂TC⁻, within the pH range of 8.9–9.7, with distribution coefficients reaching (5–6) × 10³ mL/g. Following the extraction process using PMM and PMM-Au⁰, the direct determination of tetracycline in the solid phase is possible without an elution step. This is achieved by using as the analytical signal both the intrinsic absorption and the instrumentally measured peak area of the anionic form of tetracycline, H₂TC⁻, in the matrix, with detection limits of 0.03 and 0.01 mg/L, respectively, and the fluorescence of tetracycline in PMM and PMM-Au⁰, with detection limits of 0.001 and 0.005 mg/L, respectively. The applicability of the digital colorimetry method for the quantitative determination of tetracycline based on its fluorescence in the solid phase is demonstrated. Methodologies for the determination of tetracycline using PMM and PMM-Au⁰ were developed and tested in the analysis of river and bottled water samples, biological fluid, as well as honey and milk samples. Full article

(This article belongs to the Special Issue Extraction Techniques for Sample Preparation)

► Show Figures

Graphical abstract

17 pages, 3855 KB

Open AccessReview

Recent Advances in Stimuli-Responsive Microgels and Their Biomedical Applications

by Hongtao Zhang and Yongfeng Gao

Molecules 2025, 30(22), 4457; https://doi.org/10.3390/molecules30224457 - 19 Nov 2025

Abstract

Stimuli-responsive microgels, smart polymeric particles at a micro- to sub-micro scale that are capable of undergoing reversible changes in response to external triggers, have emerged as versatile tools in the field of biomedical research. The review begins by emphasizing the importance of precise [...] Read more.

Stimuli-responsive microgels, smart polymeric particles at a micro- to sub-micro scale that are capable of undergoing reversible changes in response to external triggers, have emerged as versatile tools in the field of biomedical research. The review begins by emphasizing the importance of precise control over microgel properties, such as size, composition, and responsiveness, to harness their full potential. It delves into various synthetic methodologies, including precipitation polymerization, emulsion polymerization, and microfluidic techniques. The versatility of microgels, combined with their ability to respond to specific stimuli, holds great promise for tailored biomedical applications. By dissecting the responsive attributes of microgels and unraveling the intricate structure-property relationships they embody, this review elucidates the invaluable contributions of these remarkable smart materials to diverse biomedical applications, paving the way for future advancements in the field. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Application of Polymer-Based Materials, 2nd Edition)

► Show Figures

Figure 1

32 pages, 3290 KB

Open AccessReview

Therapeutic Potentials of the Seaweed-Derived Compounds for Alzheimer’s Disease

by Keanie Ward, Michael H. Cole, Lyn R. Griffiths, Heidi G. Sutherland, Pia Winberg, Barbara J. Meyer and Francesca Fernandez

Molecules 2025, 30(22), 4456; https://doi.org/10.3390/molecules30224456 - 19 Nov 2025

Abstract

Cognitive decline associated with healthy ageing and pathological conditions is driven by multifactorial processes, including oxidative stress, mitochondrial dysfunction and chronic neuroinflammation. Alzheimer’s Disease (AD), a progressive neurodegenerative disorder affecting cognition and behaviour, is the leading cause of dementia worldwide. Current pharmacological interventions [...] Read more.

Cognitive decline associated with healthy ageing and pathological conditions is driven by multifactorial processes, including oxidative stress, mitochondrial dysfunction and chronic neuroinflammation. Alzheimer’s Disease (AD), a progressive neurodegenerative disorder affecting cognition and behaviour, is the leading cause of dementia worldwide. Current pharmacological interventions provide modest and transient benefits, targeting limited molecular pathways with safety and cost concerns, underscoring the need for safe, accessible and multi-targeted strategies. This review explores new avenues of therapy with a focus on bioactive compounds derived from brown, red and green seaweeds and their potential to modulate key mechanisms underlying AD. Preclinical and emerging clinical studies demonstrate that phlorotannins, fucoidans, fucoxanthin, lutein, zeaxanthin, ulvan, and astaxanthin exert antioxidant, anti-inflammatory, cholinergic-modulating and neuroprotective effects. Supplementation with seaweed-derived bioactive compounds has been shown to exert molecular and cellular effects that lead to reduced amyloid burden, preservation of synaptic integrity, and enhanced cognitive performance. Collectively, seaweed-derived compounds represent promising candidates for multi-target therapeutic strategies in cognitive decline prevention in the context of AD and healthy brain ageing. Full article

(This article belongs to the Section Medicinal Chemistry)

► Show Figures

Graphical abstract

23 pages, 3857 KB

Open AccessReview

Recent Progress of Chiral Mesoporous Silica Nanostructures: From Synthesis to Applications

by Changlong Hao

Molecules 2025, 30(22), 4455; https://doi.org/10.3390/molecules30224455 - 19 Nov 2025

Abstract

Chiral mesoporous silica nanostructures (MSNs) have emerged as a cutting-edge material in nanotechnology. These nanostructures not only retain the tunable physicochemical properties of traditional MSNs—such as adjustable pore size, high surface area, and excellent biocompatibility—but also exhibit unique functionalities and biological behaviors due [...] Read more.

Chiral mesoporous silica nanostructures (MSNs) have emerged as a cutting-edge material in nanotechnology. These nanostructures not only retain the tunable physicochemical properties of traditional MSNs—such as adjustable pore size, high surface area, and excellent biocompatibility—but also exhibit unique functionalities and biological behaviors due to their helical architectures at both molecular and macroscopic levels. This inherent chirality grants chiral MSNs exceptional potential in diverse applications, including chiral catalysis, enantiomeric separation, chiral recognition, and advanced drug delivery systems. Over the past five years, substantial progress has been made in understanding their synthesis mechanisms and practical applications. This review provides a comprehensive analysis of recent advancements in chiral silica nanostructures, with a focus on the synthesis strategies and applications of chiral MSNs. Emphasis is placed on their roles in chiral recognition, drug delivery, chiral separation, nanomedicine, and asymmetric catalysis. By highlighting these developments, this review serves as a roadmap for the rational design and translational applications of chiral silica nanostructures, offering valuable guidance for unlocking their full potential. Full article

(This article belongs to the Special Issue Chiral Nanomaterials: Synthesis, Properties, and Applications)

► Show Figures

Figure 1

Journal Description

Molecules

Latest Articles

Journal Menu

Journal Browser

Highly Accessed Articles

Latest Books

E-Mail Alert

News

Topics

Conferences

Special Issues

Topical Collections

Further Information

Guidelines

MDPI Initiatives

Follow MDPI