Chemistry

24 pages, 12863 KB

Open AccessArticle

NEXAFS and XPS and Structural, Electrical and Thermal Properties of Zn and Ni Codoped Bismuth Antimonate Pyrochlore

by Sergey V. Nekipelov, Maria G. Krzhizhanovskaya, Alexandra V. Koroleva, Nikolay A. Sekushin, Vladimir A. Belyy, Olga V. Petrova and Nadezhda A. Zhuk

Chemistry 2026, 8(8), 110; https://doi.org/10.3390/chemistry8080110 - 10 Aug 2026

Abstract

The crystal structure and physicochemical properties of a new Ni/Zn codoped bismuth antimonite pyrochlore, synthesized by the solid-phase reaction method, were investigated. The most optimal outcomes of Rietveld refinement for Bi_2.7Zn_0.46Ni_0.70Sb₂O_10+Δ were achieved for [...] Read more.

The crystal structure and physicochemical properties of a new Ni/Zn codoped bismuth antimonite pyrochlore, synthesized by the solid-phase reaction method, were investigated. The most optimal outcomes of Rietveld refinement for Bi_2.7Zn_0.46Ni_0.70Sb₂O_10+Δ were achieved for the model of a disordered pyrochlore structure (sp.gr.Fd-3m:2, a = 10.46442(5) Å). Zinc and nickel atoms demonstrate an inhomogeneous mixed distribution across bismuth and antimony positions. The microstructure of the ceramic is characterized by low porosity, and is formed by faceted grains of 0.25–2 μm in diameter. The thermal expansion coefficient (TEC) increases monotonically from 7.14 × 10⁻⁶ °C⁻¹ (30 °C) to 9.80 × 10⁻⁶ °C⁻¹ (990 °C). At temperatures above 1080 °C, an atypical thermal dissociation of the pyrochlore occurs, resulting in the formation of bismuth-free compounds and two cubic phases that are stable when the sample is cooled. The Bi_2.7Zn_0.46Ni_0.70Sb₂O_10+Δ compound is characterized by a band gap width of 2.4 eV. At temperatures below 200 °C, the sample exhibits predominantly capacitive impedance characteristics. The capacitance remains constant and independent of temperature and frequency up to a maximum of 150 °C. The high-frequency relative dielectric permittivity is low and equal to 26(3). The conduction activation energy in the sample is found to be 1.30(5) eV. Two polarization processes are detected in the sample. The electrical behavior of the sample has been modeled successfully by equivalent circuits within the temperature range of 200–450 °C. According to NEXAFS and XPS data, metal cations exhibit a conventional charge state, with an antimony oxidation state of +(5−δ). Full article

(This article belongs to the Section Inorganic and Solid State Chemistry)

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19 pages, 5045 KB

Open AccessArticle

Innovative Nanomaterials for Remediation of Heavy Metal-Contaminated Soil: Electro-Structural and Vibration Analysis by Quantum DFT Insights

by Fatemeh Mollaamin and Majid Monajjemi

Chemistry 2026, 8(8), 109; https://doi.org/10.3390/chemistry8080109 - 10 Aug 2026

Abstract

Geogenic processes and human activities are both major causes of soil pollution. Soils can get toxic transition metals from the materials they are formed from, but most pollution comes from industrial and farming activities. The presence of these transition metals in soil can [...] Read more.

Geogenic processes and human activities are both major causes of soil pollution. Soils can get toxic transition metals from the materials they are formed from, but most pollution comes from industrial and farming activities. The presence of these transition metals in soil can be shown through changes in chemical, biochemical, and microbial properties, as well as how plants react. This research aims to remove transition metals like chromium (Cr), manganese (Mn), iron (Fe), zinc (Zn), tungsten (W), and cadmium (Cd) from soil using a boron nitride (BN) nanocage. The electromagnetic and thermodynamic properties of these metals when trapped in BN were studied using materials modeling. The metals are captured through chemisorption. The research looked at how Cr, Mn, Fe, Zn, W, and Cd are trapped by BN to detect soil metal cations. BN was designed in the presence of these transition metals. The covalent characteristics of these complexes show similar energy levels and a view of the partial density of states between the p states of boron and nitrogen in BN and the d states of Cr, Mn, Fe, Zn, W, and Cd in B(X)N complexes. Also, nuclear magnetic resonance (NMR) analysis showed clear peaks around Cr, Mn, Fe, Zn, W, and Cd when they were trapped in BN during atomic detection and removal from soil, although there were some variations in chemical shielding for isotropic and anisotropic tensors. Based on these results, the ability of BN (as an atom sensor) to adsorb toxic metals, metalloids, and nonmetals is ordered as: Cd > Zn > Fe > Cr > Mn ≈ W. This article suggests that elements absorbed by BN could be used to develop and improve the optoelectronic properties of BN, helping to create photoelectric devices for soil cleaning. Full article

(This article belongs to the Section Chemistry at the Nanoscale)

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19 pages, 5928 KB

Open AccessArticle

Electrocatalytic Reduction of NO to NH₃ Using N−CQDs/TiO₂ with Ohmic Contact Effect: Research and Computational Analysis

by Lei Chen, Wenting Sun, Quan Li, Wentai Wang and Dongcai Shen

Chemistry 2026, 8(8), 108; https://doi.org/10.3390/chemistry8080108 - 7 Aug 2026

Abstract

The research on semiconductor electrocatalysts has developed into an active field of study in the past decade. By constructing heterojunctions, one may efficiently overcome the limitations of semiconductors’ broad band gaps and low conductivity. This work uses a single-step hydrothermal approach to load [...] Read more.

The research on semiconductor electrocatalysts has developed into an active field of study in the past decade. By constructing heterojunctions, one may efficiently overcome the limitations of semiconductors’ broad band gaps and low conductivity. This work uses a single-step hydrothermal approach to load nitrogen-doped carbon quantum dots onto TiO₂ nanoparticles, resulting in an excellent N−CQDs/TiO₂ catalyst with an Ohmic contact effect for better NORR electrocatalytic performance under ambient circumstances. The ammonia production rate is 4242.24 μg·h⁻¹·mg⁻¹ at an applied potential of −0.90 V vs. RHE (in a 0.10 M K₂SO₄ electrolyte), and the Faradaic efficiency is 88.02%. When compared to the unmodified TiO₂ catalytic performance, the ammonia generation rate doubles, and the Faradaic efficiency increases by 42.90%. A detailed investigation of the microstructure, charge transfer, NO adsorption, and reaction pathways of N−CQDs/TiO₂ was performed using density functional theory (DFT) computations. According to the theoretical results, nitrogen doping creates an uneven charge distribution on carbon quantum dots, enhancing NO adsorption by N−CQDs. The Ohmic contact between N−CQDs and TiO₂ facilitates charge transfer. The ICOHP value is more negative during NO adsorption on N-doped carbon quantum dots, decreasing the N=O interaction and boosting the NORR, according to crystal orbital Hamilton population (COHP) research. We have established the excellent performance and catalytic mechanism of the N−CQDs/TiO₂ catalyst based on these discoveries, giving strong theoretical and experimental evidence for the creation of effective catalysts for nitrogen oxide reduction processes. Full article

(This article belongs to the Topic Green and Sustainable Catalytic Process)

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18 pages, 3291 KB

Open AccessArticle

Oxygen-Rich Carbons Prepared by K₂CO₃ Activation of Phenolic Resin for Efficient CO₂ Capture

by Yujia Yin, Yuanyuan Xu, Wenyu Shen, Ya Liu, Muslum Demir, Parya Aghamohammadi, Linlin Wang and Xin Hu

Chemistry 2026, 8(8), 107; https://doi.org/10.3390/chemistry8080107 - 3 Aug 2026

Abstract

Developing adsorbents with rapid kinetics and high adsorption capacity is essential for efficient CO₂ capture. Herein, oxygen-rich porous carbons were synthesized from phenolic resin through K₂CO₃ activation. By systematically varying the activation temperature and K₂CO₃/precursor [...] Read more.

Developing adsorbents with rapid kinetics and high adsorption capacity is essential for efficient CO₂ capture. Herein, oxygen-rich porous carbons were synthesized from phenolic resin through K₂CO₃ activation. By systematically varying the activation temperature and K₂CO₃/precursor ratio, the evolution of pore structure and its influence on CO₂ adsorption behavior were comprehensively investigated. The reaction between K₂CO₃ and the carbon matrix generated abundant micropores while preserving oxygen-containing surface functionalities, leading to enhanced adsorption affinity toward CO₂ molecules. The optimized carbon exhibited a high specific surface area of 1065 m² g⁻¹ and a narrow micropore volume of 0.54 cm³g⁻¹, delivering equilibrium CO₂ uptake capacities of 5.48 and 3.92 mmol g⁻¹ at 0 and 25 °C under 1 bar, respectively. In-depth analysis revealed that narrow microporosity played a more dominant role than total surface area in determining adsorption performance. Moreover, the optimized adsorbent showed a CO₂/N₂ selectivity of 15; rapid adsorption kinetics, with 90% of equilibrium capacity achieved within 4.5 min; and a dynamic CO₂ capture capacity of 0.91 mmol g⁻¹. The moderate isosteric heat of adsorption (20–36 kJ mol⁻¹) and excellent cyclic stability further confirmed the physisorption-dominated nature of the process. This work highlights the synergistic role of ultramicropore engineering and oxygen-containing surface functionalities in designing efficient porous carbon adsorbents for carbon capture. Full article

(This article belongs to the Special Issue Sustainable Chemistry for a Net Zero World)

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24 pages, 2653 KB

Open AccessArticle

Passerini–Smiles Pathways to Spirooxindoles: Isatin-Based Scaffolds in Anticancer Drug Design

by Carolina S. Marques, Aday González-Bakker and José M. Padrón

Chemistry 2026, 8(8), 106; https://doi.org/10.3390/chemistry8080106 - 3 Aug 2026

Abstract

The underexplored Passerini–Smiles reaction (PSR), a variant of the 3-component Passerini reaction (3CPR), was successfully employed to create a tailored library of phenoxy-indoline carboxamide derivatives based on a fragment-based hybrid drug design strategy. Under mild conditions, inexpensive and commercially available isatin was utilized [...] Read more.

The underexplored Passerini–Smiles reaction (PSR), a variant of the 3-component Passerini reaction (3CPR), was successfully employed to create a tailored library of phenoxy-indoline carboxamide derivatives based on a fragment-based hybrid drug design strategy. Under mild conditions, inexpensive and commercially available isatin was utilized as a privileged carbonyl core, combined with electron-deficient phenols to establish a highly functionalized framework. Post-Passerini–Smiles transformations leveraged this strategic layout to provide a step-economical route to a complementary library of three-dimensional spirooxindole hybrids derived from the PS adducts. This study reinforces the relevance of combining structural hybridization with multicomponent reaction strategies in the discovery of potential anticancer active pharmaceutical ingredients (APIs). Both libraries were evaluated against six human solid-tumor cell lines, including non-small cell lung carcinoma, cervical and colon adenocarcinoma, and breast and pancreatic cancers. The most active compound 4gaa exhibited GI₅₀ values below 10 μM for most of the tested cancer cell lines. Full article

(This article belongs to the Special Issue Nature-Inspired Scaffolds in Medicinal Chemistry: An Old Push for Modern Drug Discovery—Second Edition)

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12 pages, 951 KB

Open AccessArticle

Controlling Nickel Catalyst Reactivity by Controlling Molecular Catalyst Speciation

by Joseph J. Kuchta III, Laura C. Maybach, Alexia M. Bradbury, Sarah M. Moody, Mollie C. Morrow, Pooja J. Ayare, D. M. S. C. Dissanayake and Aaron K. Vannucci

Chemistry 2026, 8(8), 105; https://doi.org/10.3390/chemistry8080105 - 1 Aug 2026

Abstract

Controlling molecular catalyst speciation under reaction conditions can be an effective approach for extending catalyst lifetimes and controlling selectivity. Anchoring molecular catalysts to solid supports, to generate hybrid catalysts, is a means for preventing bimolecular catalyst interactions and preventing the formation of catalyst [...] Read more.

Controlling molecular catalyst speciation under reaction conditions can be an effective approach for extending catalyst lifetimes and controlling selectivity. Anchoring molecular catalysts to solid supports, to generate hybrid catalysts, is a means for preventing bimolecular catalyst interactions and preventing the formation of catalyst species such as dimers and multimers. Here we compare a series of different anchoring motifs for molecular nickel catalysts bound to metal oxide supports. The catalysts are anchored to the supports through functional groups on the ligand framework, and carboxylate, ester, and silanol groups are compared in terms of synthetic ease, anchoring stability, catalyst loading on the surface, and catalytic behavior with respect to Suzuki–Miyaura cross-coupling. The results show that covalent bonds between the molecular catalysts and the oxide support lead to increased catalyst surface loadings and higher surface loading, which helps avoid mass transport limitations during catalysis. In addition, the metal–ester-bound catalysts exhibit support-dependent reactivity, which is unique and different from the carboxylate and silanol anchoring groups. Infrared and X-ray photoelectron spectroscopy are used to characterize the molecular nature of the catalysts, and reactivity trends show that the covalent bonding of the catalysts to the surface controls catalyst speciation with respect to geometry and valency, which influences catalytic activity. Full article

(This article belongs to the Special Issue Celebrating the 50th Anniversary of Professor Valentine Ananikov)

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24 pages, 5838 KB

Open AccessArticle

Proposal of a Pulse Charging Method for Alkaline Primary Batteries Using a Self-Built Arduino-Based Prototype and an Open Source Protocol

by Maria Pia Sammartino, Giovanni Visco, Mauro Castrucci, Micaela Abruzzese and Mauro Tomassetti

Chemistry 2026, 8(8), 104; https://doi.org/10.3390/chemistry8080104 - 29 Jul 2026

Abstract

Batteries, especially useful for portable instruments, are the most widely used alternative to direct current. Their operating principle is based on irreversible or reversible chemical reactions, which are called primary (non-rechargeable) or secondary (rechargeable), respectively. Primary batteries never completely discharge and their residual [...] Read more.

Batteries, especially useful for portable instruments, are the most widely used alternative to direct current. Their operating principle is based on irreversible or reversible chemical reactions, which are called primary (non-rechargeable) or secondary (rechargeable), respectively. Primary batteries never completely discharge and their residual charge depends on the energy demand of the instrument in which they are used. Even if correctly disposed of, therefore, and with the possibility of recycling the constituent materials and purchasing and using consciously, only 2 of the 3Rs, namely “Recycle” and “Reuse”, are respected; recovering the residual charge would also allow compliance with the last of the 3Rs, namely “Reduce”. Direct energy recovery methods have been proposed but the simplest method to “reduce”, analogously to what is done with secondary batteries, remains being recharging, which, unfortunately, is a risky operation, as it can cause the battery to explode or leak corrosive solution. Following our previous research, in which we proposed a method for measuring the residual charge of alkaline batteries, we now propose a method for charging the batteries whose residual charge we measured in our previous work. In this research, a hand-built external circuit, Arduino UNO R3, was used to generate the charging pulses and as a controller and measuring instrument and an Open-Source protocol for the recharging process. The results demonstrated the feasibility of the method, as the voltage of 50% of the batteries increased and, further, only 18% of the batteries leaked and none exploded. Full article

(This article belongs to the Section Electrochemistry and Photoredox Processes)

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19 pages, 6603 KB

Open AccessArticle

Preparation of Silica/Natural Rubber Latex Nanocomposite Emulsion and Its Application in Tire Puncture Sealing

by Weiting Lin, Yue Cai, Wenlong Zhang and Jie Feng

Chemistry 2026, 8(8), 103; https://doi.org/10.3390/chemistry8080103 - 27 Jul 2026

Abstract

Developing tire sealants that effectively combine rapid sealing and mechanical durability remains a key challenge. This study presents a novel, high-performance sealant based on a natural rubber latex (NRL) matrix reinforced with uniformly dispersed hydrophobic nano-silica (SiO₂). A stable and homogeneous [...] Read more.

Developing tire sealants that effectively combine rapid sealing and mechanical durability remains a key challenge. This study presents a novel, high-performance sealant based on a natural rubber latex (NRL) matrix reinforced with uniformly dispersed hydrophobic nano-silica (SiO₂). A stable and homogeneous composite was achieved by employing sodium dodecylbenzene sulfonate (SDBS) as a surfactant and using ultrasonic processing. In simulated puncture tests, the optimized composite demonstrated superior performance, reducing the critical repair distance by approximately 3 km and the tire pressure loss by more than 75% compared to the reference samples. The repair mechanism was investigated through rheological analysis, electron microscopy, and mechanical testing. The enhanced performance correlates with electrical double-layer compression and particle aggregation and is accompanied by increased storage modulus and viscosity recovery that contribute to the sealing efficiency. These effects collectively increase the sealant’s storage modulus, enabling rapid sealing and effective resistance to shear under mechanical loading during tire rotation. This work provides both a practical formulation strategy and mechanistic insight for the development of next-generation, high-performance tire puncture sealant. Full article

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18 pages, 2652 KB

Open AccessArticle

Co–Cu Ferrites on Ceria–Carbon Hybrid Nanocomposites and Waste Oil-Derived Activated Carbon for Methanol Decomposition

by Gloria Issa, Ivalina Trendafilova, Momtchil Dimitrov, Ivan Dimitrov, Stefan P. Marinov, Nikolay Velinov, Daniela Kovacheva, Daniela Karashanova, Iskra Piroeva and Ivanka Stoycheva

Chemistry 2026, 8(8), 102; https://doi.org/10.3390/chemistry8080102 - 27 Jul 2026

Abstract

This study focuses on the synthesis of Co_0.5Cu_0.5Fe₂O₄ mixed ferrites supported on nanoporous carbon materials. The carbon supports were derived from two mixtures: a mixture of spent motor oil and pine wood chips (designated as AC-A), [...] Read more.

This study focuses on the synthesis of Co_0.5Cu_0.5Fe₂O₄ mixed ferrites supported on nanoporous carbon materials. The carbon supports were derived from two mixtures: a mixture of spent motor oil and pine wood chips (designated as AC-A), and a mixture of spent motor oil and crushed coal obtained from the Chukurovo mine (designated as AC-B). Additionally, two types of carbon components—nanodiamond and graphene oxide—were used for the synthesis of nanosized ceria-based hybrid nanocomposites. The results revealed that the active phase deposited on the carbon supports consists of a complex mixture of finely dispersed ferrite nanoparticles as well as small CeO₂ crystallites in the case of hybrid nanocomposites. The dispersion and phase composition of the deposited copper–cobalt ferrites depends on the textural properties of the carbon supports. Among the investigated materials, the graphene oxide-modified composites exhibited the highest catalytic activity at 670 K, achieving a methanol conversion of 90%. Full article

(This article belongs to the Section Chemistry at the Nanoscale)

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27 pages, 4795 KB

Open AccessArticle

Optimization of Polysaccharide Extraction from Termitomyces albuminosus by Ultrasound-Assisted Extraction and Comparative Analysis of Structural Characteristics and Antioxidant Activity

by Zhenjiang Li, Youpeng Tuo, Xiaofang Tang, Li Ye, Jing Chen, Lan Chen, Fangyuan Zeng and Changsheng Qiao

Chemistry 2026, 8(8), 101; https://doi.org/10.3390/chemistry8080101 - 25 Jul 2026

Abstract

Edible mushroom polysaccharides have attracted considerable attention because of their diverse biological activities, particularly their antioxidant potential. However, efficient extraction of these polysaccharides remains challenging due to the rigid chitin–β-glucan network of fungal cell walls. In this study, polysaccharides from Termitomyces albuminosus were [...] Read more.

Edible mushroom polysaccharides have attracted considerable attention because of their diverse biological activities, particularly their antioxidant potential. However, efficient extraction of these polysaccharides remains challenging due to the rigid chitin–β-glucan network of fungal cell walls. In this study, polysaccharides from Termitomyces albuminosus were extracted using hot water extraction (HWE), ultrasound-assisted extraction (UAE), and ultrasound-assisted aqueous two-phase extraction (UA-ATPE). Extraction conditions for each method were optimized using Box–Behnken response surface methodology, and the effects of different extraction strategies on polysaccharide yield, physicochemical properties, and antioxidant activity were systematically compared. Among the three methods, UAE produced the highest polysaccharide yield (110.32 ± 3.68 mg/g). The extraction strategy significantly influenced the molecular weight distribution and monosaccharide composition of the crude polysaccharides. The crude UAE extract was further purified by DEAE-52 anion-exchange chromatography, yielding the major antioxidant-active fraction eluted with 0.1 M NaCl (designated ATPs-0.1M), which was identified as an acidic heteropolysaccharide with an average molecular weight of 6.37 kDa and composed primarily of glucose, mannose, galactose, xylose, glucuronic acid, rhamnose, and fucose. In vitro antioxidant assays demonstrated that TAPs-0.1M exhibited stronger DPPH radical scavenging, hydroxyl radical scavenging, and ferric reducing activities than the other purified fractions under the tested conditions. The results indicate that different extraction strategies are associated with distinct physicochemical characteristics and antioxidant activities of T. albuminosus polysaccharides. These findings provide a practical basis for selecting appropriate extraction methods and support the further development of T. albuminosus polysaccharides as natural antioxidant ingredients. Full article

(This article belongs to the Topic Natural Bioactive Compounds as a Promising Approach to Mitigating Oxidative Stress—Second Edition)

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35 pages, 9850 KB

Open AccessSystematic Review

Research Progress on Preparation Technology and Applications of Bis(hydroxymethyl)tricyclodecane

by Yi Xia, Rong Fan, Dansen Shang, Xinrong Yao, Xi Liu and Zhuo Yi

Chemistry 2026, 8(7), 100; https://doi.org/10.3390/chemistry8070100 - 21 Jul 2026

Abstract

Polymers based on tricyclic decane skeleton in the role of high-performance polycarbon, polyester, polyacrylate, etc., are used in optical equipment, dental restoration, photoresist, and other fields because of their rigid ring structure and corresponding excellent heat/weather/impact/scratch resistance. The preparation process of monomer tricyclodidecane [...] Read more.

Polymers based on tricyclic decane skeleton in the role of high-performance polycarbon, polyester, polyacrylate, etc., are used in optical equipment, dental restoration, photoresist, and other fields because of their rigid ring structure and corresponding excellent heat/weather/impact/scratch resistance. The preparation process of monomer tricyclodidecane dimethanol is complex and has engineering safety problems. Also, it has been monopolized by a few enterprises for a long time, and the price is expensive. There is a lack of systematic reviews on the synthesis of tricyclodecane dimethanol. In this paper, focusing on the preparation process of tricyclic decane dimethanol, the preparation process of bicyclic decane dimethanol to be prepared by dicyclopentadiene is summarized, including the reaction path, catalytic system and separation method, and the homogeneous catalysis, aqueous/organic two-phase catalysis and heterogeneous catalysis in the hydroformylation of high-carbon olefins are discussed, as well as the difference between stripping, extraction, membrane separation and other methods in the separation methods of catalyst and product. Then, the current research status at home and abroad is summarized, and the advantages and disadvantages of the above reaction methods are analyzed according to the reaction system, catalyst used, solvent, reaction conditions, and final reaction level. Finally, the downstream application and market of tricyclic decane dimethanol are analyzed. It provides a reference for the design and optimization of the preparation process of tricyclodecane dimethanol. Full article

(This article belongs to the Section Chemistry of Materials)

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17 pages, 10008 KB

Open AccessArticle

Sustainable Coloration and Functionalization of Cotton Fabric Dyed with Bombax ceiba Flower Extract and Bio-Mordants

by Saba Tariq, Imran Ahmad Khan, Kashif Javed, Asfandyar Khan, Ahmad Fraz, Zeeshan Tariq, Nazmul Islam and Fiaz Hussain

Chemistry 2026, 8(7), 99; https://doi.org/10.3390/chemistry8070099 - 19 Jul 2026

Abstract

This research examines the dyeing of cotton fabric using a natural dye, extracted from Bombax ceiba flowers, aiming primarily to carry out the entire dyeing process without conventional inorganic mordants. The dye was extracted in an alkaline medium, while three agricultural waste-derived bio-mordants, [...] Read more.

This research examines the dyeing of cotton fabric using a natural dye, extracted from Bombax ceiba flowers, aiming primarily to carry out the entire dyeing process without conventional inorganic mordants. The dye was extracted in an alkaline medium, while three agricultural waste-derived bio-mordants, eucalyptus bark, onion peel, and aloe vera peel, were used to enhance the functional textile properties. These natural tannin-based mordants and phenolic mordants enabled the uptake of dye in an efficient way without releasing toxic chemicals, unlike the conventional metallic mordants. Various concentrations of each mordant were used in the preparation of dyed cotton samples, while NaCl was added in different concentrations to boost the exhaustion process. Among the three types of mordants tested, eucalyptus bark provided the best results, giving samples with a high washing fastness (rating of 4–5) and good rubbing fastness (rating of 3–4 on the gray scale). The progressively darker peach colors were achieved by adding more concentration of the eucalyptus mordant. Onion peel-mordanted samples ranged in color from dark yellow to orange, whereas aloe vera led to a unique peach color. Given the inherent antibacterial and antioxidant properties of Bombax ceiba, the dyed fabrics also possessed functional bioactive characteristics, which were further improved by the addition of bio-mordants. Furthermore, the ultraviolet protection factor (UPF) of the dyed fabric was approximately threefold higher than that of the undyed fabric, indicating a significant enhancement in UV-shielding performance after dyeing. This study conclusively demonstrates that bio-mordants serve as eco-friendly alternatives to chemical mordants, offering excellent colorfastness, diverse aesthetic possibilities, and functional properties, thereby supporting sustainable textile coloration practices. Full article

(This article belongs to the Topic Valorization of Natural Products and Agro-Food Residues)

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15 pages, 11627 KB

Open AccessArticle

Spectrofluorimetric Analysis of Amyloid Degradation Using Shankhapushpi Extract/Zinc Oxide Nanoflower—An In Vitro Study

by Tharun Asaithambi, Naga Snigdha Syamala Bandhakavi, Pavithra Arikrishnan, Sarvesh Sridharan, Sania Ullas, Saranya Udayakumar, Agnishwar Girigoswami and Koyeli Girigoswami

Chemistry 2026, 8(7), 98; https://doi.org/10.3390/chemistry8070098 - 15 Jul 2026

Abstract

Amyloidosis encompasses a spectrum of diseases in which insoluble protein aggregates are deposited in various parts of the body, including the brain, giving rise to Alzheimer’s disease, prion disease, and Parkinson’s disease, and also being a manifestation of Type II diabetes. The soluble [...] Read more.

Amyloidosis encompasses a spectrum of diseases in which insoluble protein aggregates are deposited in various parts of the body, including the brain, giving rise to Alzheimer’s disease, prion disease, and Parkinson’s disease, and also being a manifestation of Type II diabetes. The soluble protein gets aggregated as insoluble plaques by an unknown phenomenon, leading to the disease. If an agent is developed that can dissociate or disintegrate these plaques, it can be proposed as a lead molecule for amyloid dissociation. In the present study, we have taken the aqueous extract of a herb, Shankhapushpi (Convolvulus pluricaulis), and synthesized zinc oxide nanoflowers (ZnO-NFs-Skp). The plant extract was characterized using phytochemical analysis, and the ZnO-NFs-Skp were characterized using various photophysical tools like dynamic light scattering, zeta potential, XRD, FTIR, and scanning electron microscopy (SEM). The in vitro cytotoxicity of the ZnO-NFs-Skp was assessed in the PC12 cell line using an MTT assay and a fluorescent dual-staining assay. The effect of ZnO-NFs-Skp on zebrafish embryos was evaluated for in vivo biocompatibility. Finally, the amyloid degradation of the ZnO-NFs, after incubation with preformed insulin amyloids, the model amyloid protein used for the amyloid study, was evaluated at different time intervals using the Thioflavin T fluorescence assay. The results indicated that the Shankhapushpi extract had alkaloids, coumarins, and glycosides. The hydrodynamic diameter of ZnO-NF-Skp was found to be 181 nm, and the zeta potential was −17.7 mV. SEM imaging showed a carnation flower-like morphology with a petal thickness of 30 ± 5 nm. The ZnO-NFs-Skp did not induce any toxicity up to a dose of 160 μg/mL, both in vitro and in vivo. The amyloid degradation study revealed 38% degradation of the IA, 24 h after incubation at 37 °C. SEM analysis also evidenced the degradation of IA. Compared to ZnO nanoparticles (18%), ZnO-NFs-Skp could degrade almost double (35%) the amount of IA after 12 h incubation, as shown by the ThT assay. Overall, the data suggested that Shankhapushpi-mediated ZnO-NFs (ZnO-NFs-Skp) are biocompatible and have a good capacity to degrade amyloids. In the future, amyloid degradation using Aβ-42 and the prion protein needs to be investigated. Full article

(This article belongs to the Special Issue Fluorescent Chemosensors and Probes for Detection and Imaging)

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18 pages, 20132 KB

Open AccessArticle

Local Strain in Pt–Ni Bulk and Nanoparticles

by Jairo A. Martínez-Uribe, Joaly Delgado-Alvarez, J. Jesús Velázquez Salazar, Daniel Bahena Uribe, Miguel José-Yacamán and Sergio J. Mejía-Rosales

Chemistry 2026, 8(7), 97; https://doi.org/10.3390/chemistry8070097 - 15 Jul 2026

Abstract

Understanding the mechanical behavior of bimetallic nanoparticles under compressive stress is relevant for the use of these nanostructures in catalysis and nanomechanics. In this work, we present molecular dynamics (MD) simulations of compressive deformation in Pt–Ni nanoparticles—and bulk systems for comparison—with varying compositions [...] Read more.

Understanding the mechanical behavior of bimetallic nanoparticles under compressive stress is relevant for the use of these nanostructures in catalysis and nanomechanics. In this work, we present molecular dynamics (MD) simulations of compressive deformation in Pt–Ni nanoparticles—and bulk systems for comparison—with varying compositions (Pt_xNi_1−x) and local distributions. The simulations show that the mechanical response is governed by local strain fields, which influence both elastic and plastic regimes. The final trajectories were analyzed by dislocation analysis (DXA), simulated STEM imaging, and geometric phase analysis (GPA), which allowed the obtention of high-resolution strain maps. Analysis of von Mises stress distribution allowed us to correlate composition and atomic ordering with the formation and evolution of dislocations in the nanoparticles. The Pt_0.5Ni_0.5 intermetallic compound exhibits superior mechanical performance under uniaxial compression; in bulk, this composition also shows enhanced elastic energy storage. In polycrystalline nanoparticles, energy dissipation increased with decreasing average grain size, which is attributed to elevated plastic activity induced by the presence of multiple crystallographic orientations. GPA results show that it is possible to discriminate between compositions differing by as little as

Δ x

= 0.1 based on local strain distributions, and the comparison with GPA performed on real STEM micrographs gives a fair agreement. GPA and atomistic stress maps reveal how strain fields evolve during compression and how they correlate with the development of plasticity. These findings highlight the critical role of local structural heterogeneities in dictating the mechanical behavior of nanoscale Pt–Ni systems, and provide strong evidence that GPA can correlate local strain and composition in real high-resolution micrographs. Full article

(This article belongs to the Section Chemistry at the Nanoscale)

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13 pages, 7498 KB

Open AccessCommunication

Polymorph-Dependent Oxidation Activity of MnO₂: Influence of Surface Water, Morphology, and Surface Area in Benzylic Oxidation

by Sathish Kumar Lageshetty, Baskar Nammalwar, Richard A. Bunce and Kevin D. Ausman

Chemistry 2026, 8(7), 96; https://doi.org/10.3390/chemistry8070096 - 10 Jul 2026

Abstract

Direct comparisons of MnO₂ polymorphs in synthetic benzylic oxidation remain limited, particularly regarding the combined effects of crystallinity, morphology, surface area, and surface-associated water. In this study, α-, β-, and γ-MnO₂ were prepared by hydrothermal methods and benchmarked against nano-MnO₂ [...] Read more.

Direct comparisons of MnO₂ polymorphs in synthetic benzylic oxidation remain limited, particularly regarding the combined effects of crystallinity, morphology, surface area, and surface-associated water. In this study, α-, β-, and γ-MnO₂ were prepared by hydrothermal methods and benchmarked against nano-MnO₂ for the oxidation of diphenylmethane to benzophenone. XRD, TGA, FTIR, BET, and SEM analyses confirmed phase-defined crystalline polymorphs, distinct wire- or rod-like morphologies, and marked differences in surface area and water retention. Nano-MnO₂ exhibited a porous, poorly crystalline nanoscale structure with the highest surface area and delivered the greatest oxidation efficiency under aerobic, atmospheric, and anaerobic conditions. Among the crystalline phases, α-MnO₂ showed the highest activity despite its lower BET surface area than β-MnO₂, indicating that surface-associated water is more influential than surface area alone. The loss of activity after drying at 120 °C, prolonged storage, or reuse further supports the critical role of labile surface-bound water. Overall, this work establishes a structure–morphology–water–reactivity relationship for MnO₂-mediated arylmethylene oxidation and identifies water-rich nano-MnO₂ as the most effective material for converting benzylic substrates to ketones. Full article

(This article belongs to the Section Chemistry at the Nanoscale)

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14 pages, 1849 KB

Open AccessArticle

A Green Approach for Optimizing Naringin Extraction from the Fresh Albedo of the Main Three Grapefruit (Citrus paradisi) Varieties Cultivated in Mexico

by Odette Flores-Pérez, Ángel R. Flores-Sosa, José E. Báez, Diana López-Fitz, Areli Rodríguez-Ontiveros, Moustapha Bah, Alejandro Nuñez-Vilchis, Jesica Escobar-Cabrera and Eloy Rodríguez-deLeón

Chemistry 2026, 8(7), 95; https://doi.org/10.3390/chemistry8070095 - 7 Jul 2026

Abstract

Citrus fruits are a significant source of flavonoids. Of all the citrus fruits, Citrus paradisi (grapefruit) presents the highest concentration of the flavonoid naringin, a compound offering a variety of human health benefits and applications in the pharmaceutical, food, and cosmetic industries. Commonly, [...] Read more.

Citrus fruits are a significant source of flavonoids. Of all the citrus fruits, Citrus paradisi (grapefruit) presents the highest concentration of the flavonoid naringin, a compound offering a variety of human health benefits and applications in the pharmaceutical, food, and cosmetic industries. Commonly, when a citrus fruit is consumed, the peel and seeds are discarded, resulting in approximately 50% waste, making the potential use of citrus waste in order to reduce environmental impact a research priority. The present study used fresh grapefruit albedo to extract naringin via eco-friendly methods, such as ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE), which were compared against the conventional reflux extraction procedure. Furthermore, the presence of naringin was confirmed by nuclear magnetic resonance (NMR) spectroscopy, while naringin content was determined via HPLC-DAD analysis. The results obtained show that the pink grapefruit variety was the optimal source for extracting the flavonoid of interest, producing the highest content (3.41 g/kg), followed by the red (2.47 g/kg) and white (1.70 g/kg) varieties. The UAE method was observed to reduce the extraction time significantly, to only 10 min, which is up to 30-and -fold less than the extraction times obtained using conventional (5 h) and MAE (40 min) methods, respectively. These results prove the usefulness of UAE as a simple, fast, efficient, and eco-friendly method for extracting naringin from fresh grapefruit albedo, via the use of a green solvent such as ethanol. In addition, the present study is the first to conduct a comparative analysis of naringin content in the three main grapefruit varieties grown in Mexico. Full article

(This article belongs to the Topic Valorization of Natural Products and Agro-Food Residues)

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38 pages, 11716 KB

Open AccessReview

A Comprehensive Review on Hydrothermally Tuning SrTiO₃ for Efficient Photocatalytic Applications: Water Remediation and Water Splitting

by Soujanya Nethi, Pallavi Saxena and Anupam Singha Roy

Chemistry 2026, 8(7), 94; https://doi.org/10.3390/chemistry8070094 - 6 Jul 2026

Abstract

Global requirement of clean, cost-effective and sustainable energy has stimulated massive research and development in photocatalytic materials that have the potential to harvest solar based energy while mitigating the environmental issues. Among various materials, perovskite oxides have emerged as a promising energy resource. [...] Read more.

Global requirement of clean, cost-effective and sustainable energy has stimulated massive research and development in photocatalytic materials that have the potential to harvest solar based energy while mitigating the environmental issues. Among various materials, perovskite oxides have emerged as a promising energy resource. Owing to the structural versatility, optical and electrical properties, chemical inertness allows the use of material of multifunctional prospects. Currently Strontium titanate (SrTiO₃), a vital perovskite oxide having a band gap nearly ~3.2 eV, is showing significant function for photocatalytic water splitting, carbon dioxide conversion and degradation of organic pollutants. Though within the UV spectrum, its intrinsic photocatalytic behavior is limited to approaches such as graphene junctions, noble-metal support, and post-synthetic heat treatment seem to promote the adsorption within visible-light. Strontium titanate also demonstrates photo charge separation efficiency, and long-term catalytic durability. Moreover, modifications and hydrothermal synthesis have proven extremely efficient for nano-based engineering, control over crystal diameter, defects, and shape, which can result in magnificent composites that can be promising substitutes. Therefore, further research is imperative regarding these material application prospects. This comprehensive review provides insights into details on the potential of nanoengineering and composite approaches to reduce the inherent limitations of perovskite oxides, especially Strontium titanate, and enabling additional applications in next-generation photovoltaic and solar energy harvesting technologies. Full article

(This article belongs to the Special Issue Photocatalytic Process for Water Remediation and Water Splitting)

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32 pages, 3209 KB

Open AccessReview

Coumarin Derivatives as Inhibitors of Pathological Protein Aggregation, Mechanistic Basis of β-Sheet Intercalation, Structure–Activity Relationship, and Multi-Target Therapeutic Design—A Critical Review of the Computational and Biophysical Evidence

by Huda Masri

Chemistry 2026, 8(7), 93; https://doi.org/10.3390/chemistry8070093 - 3 Jul 2026

Abstract

Natural coumarins are a structurally privileged group of bioactive benzopyranone lactones widely spread across the Apiaceae, Rutaceae, and Leguminosae families, and hold significant potential as inhibitors of pathological protein aggregation in Alzheimer’s disease, Parkinson’s disease, and type 2 diabetes mellitus. The [...] Read more.

Natural coumarins are a structurally privileged group of bioactive benzopyranone lactones widely spread across the Apiaceae, Rutaceae, and Leguminosae families, and hold significant potential as inhibitors of pathological protein aggregation in Alzheimer’s disease, Parkinson’s disease, and type 2 diabetes mellitus. The fully planar, rigid bicyclic structure of the coumarin nucleus (~3.4–3.5 Å thickness) is geometrically compatible with intercalative π–π stacking with aggregation-nucleating aromatic residues, including Phe19 of Aβ(1–42), providing a mechanistically coherent pharmacophoric basis for anti-aggregation activity according to computational and indirect biophysical evidence. This review critically evaluates the peer-reviewed literature on naturally occurring coumarins and their synthetic derivatives as candidate β-sheet intercalators, with analysis of SAR at C-3 to C-8 positions; multi-target-directed ligand designs with dual activities of inhibiting AChE, BACE-1, GSK-3β, and MAO-B, and as blood–brain barrier-penetrating neuroprotective agents validated in cellular and rodent models. The critical analysis identifies the translational gap between in vitro IC₅₀ values and attainable brain drug concentrations as the primary pharmacological obstacle. It identifies the absence of systematic investigation of coumarin against IAPP, a directly relevant amyloid target in metabolic neurodegeneration, as the most significant unmet research priority in the field. Full article

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18 pages, 2012 KB

Open AccessArticle

Saponin-Enriched Fraction of Sarcomphalus joazeiro: Chemical Characterization, Silver Nanoparticle Synthesis, and Their Mutual Antibiotic-Modifying Potential

by Natália Kelly Gomes de Carvalho, Mariana Pereira da Silva, Débora Odília Duarte Leite, Fazia Fernandes Galvão Rodrigues, Joice Barbosa do Nascimento, Milena Lima Guimarães, Helinando Pequeno de Oliveira, Lucicléia Barros de Vasconcelos, Maryana Melo Frota, Josean Fechine Tavares, Thiago Araújo de Medeiros Brito, Fabiola Fernandes Galvão Rodrigues and José Galberto Martins da Costa

Chemistry 2026, 8(7), 92; https://doi.org/10.3390/chemistry8070092 - 1 Jul 2026

Abstract

Antibiotic resistance has emerged as a major global health challenge, underscoring the urgent need for alternative therapeutic strategies capable of enhancing the efficacy of existing antibiotics. In this context, saponin-based nanomaterials have attracted considerable attention due to their potential as antibiotic-modulating systems. This [...] Read more.

Antibiotic resistance has emerged as a major global health challenge, underscoring the urgent need for alternative therapeutic strategies capable of enhancing the efficacy of existing antibiotics. In this context, saponin-based nanomaterials have attracted considerable attention due to their potential as antibiotic-modulating systems. This study investigated a saponin-enriched fraction obtained from the bark of Sarcomphalus joazeiro Mart. (SEF-4), its application in the green synthesis of silver nanoparticles, and the antibiotic-modulating potential of the resulting nanoformulation. SEF-4 was obtained from the ethanolic bark extract through liquid–liquid partitioning (52% yield), followed by column chromatographic purification and chemical characterization using LC-ESI-QTOF-MS. The purified fraction was subsequently employed as both a reducing and stabilizing agent for the synthesis of silver nanoparticles (putative AgNP-SEF-4), which were physicochemically characterized. Antibacterial activity and antibiotic-modulating effects were evaluated using the broth microdilution method against standard and multidrug-resistant bacterial strains. LC-ESI-QTOF-MS analysis enabled the putative identification of five jujubogenin-type triterpenoid saponins bearing tetra-, penta-, and hexasaccharide moieties with distinct glycosylation profiles; however, the precise sugar sequence, monosaccharide composition, and glycosidic linkage positions remain to be confirmed through complementary NMR and hydrolysis studies. Although neither SEF-4 nor putative AgNP-SEF-4 displayed clinically relevant intrinsic antibacterial activity, the nanoformulation significantly enhanced the activity of aminoglycoside antibiotics. The most pronounced modulatory effects were observed against Klebsiella pneumoniae ATCC 1705 in combination with amikacin and against both standard and multidrug-resistant Escherichia coli strains when combined with gentamicin or amikacin. These findings highlight the potential of putative AgNP-SEF-4 as an antibiotic adjuvant capable of potentiating aminoglycoside efficacy and increasing bacterial susceptibility, including in multidrug-resistant strains. Full article

(This article belongs to the Section Chemistry of Natural Products and Biomolecules)

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