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Volume 7
Issue 1
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Chemistry, Volume 7, Issue 1 (February 2025) – 27 articles

Cover Story (view full-size image): Aromaticity is one of the most important concepts in organic chemistry, and the proposed adaptive aromaticity (aromaticity in both the S0 and T1 states) breaks the limitation of traditional rules. In recent years, although adaptive aromatic compounds have been expanded, adaptive aromatics containing metal-centered radicals have not been reported. Here, we carry out density functional theory calculations to explore the aromaticity of the corresponding radicals based on osmapentalyne and osmapentalenes. Our findings reveal that the corresponding radicals of adaptive aromatic osmapentalene exhibit aromaticity regardless of the radicals formed by oxidation or reduction, supported by a series of aromaticity indices. Furthermore, the spin density localization on the metal center is the key factor for the radicals to achieve aromaticity. View this paper
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9 pages, 2847 KiB  
Communication
Crystalline Diradical Dianions and Radical Anions of Indenofluorenediones
by Xue Dong, Tao Wang, Yu Zhao, Quanchun Sun, Shuxuan Tang, Yue Zhao and Xinping Wang
Chemistry 2025, 7(1), 27; https://doi.org/10.3390/chemistry7010027 - 19 Feb 2025
Viewed by 170
Abstract
Fluorenone derivatives represent promising candidates for electron-transport materials in organic electronic devices. Given that anionic species serve as electron-transfer carriers in electron-transport materials, it is highly desirable to isolate and characterize the radical anions and dianions of indenofluorened derivatives (IFO). In this work, [...] Read more.
Fluorenone derivatives represent promising candidates for electron-transport materials in organic electronic devices. Given that anionic species serve as electron-transfer carriers in electron-transport materials, it is highly desirable to isolate and characterize the radical anions and dianions of indenofluorened derivatives (IFO). In this work, the reduction of three indenofluorenedione derivatives (IFO, 1, 2 and 3) with potassium resulted in three radical anion salts (1K[(crypt-222)], 2K[(crypt-222)] and 3K) and one dianion salt (2[K(crypt-222)]2). Single-crystal X-ray diffraction and electron paramagnetic resonance (EPR) spectroscopy reveal that 1K[(crypt-222)] and 2K[(crypt-222)] have a full delocalization of the unpaired electron which is supported by calculated spin density distributions. We demonstrate that the polarization of electron spin in 3K is induced by potassium ion coordination through single-crystal X-ray structure analysis and DFT calculations, suggesting the electrostatic effect by potassium ion has a significant influence on the spin density modulation. Superconducting quantum interference device (SQUID) measurements and DFT calculations show that 2[K(crypt-222)]2 has an open-shell singlet base with a large singlet-triplet energy gap (ΔEos-t = −7.40 kcal mol−1) so that the excited triplet state is not accessible at room temperature. Full article
(This article belongs to the Special Issue Open-Shell Systems—a Memorial Issue Dedicated to Professor Masayoshi Nakano)
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19 pages, 11004 KiB  
Article
The Influence of Electron Beam Irradiation on the Performance of Hydrogenation Catalysts Containing Co and Carboneous Particles on Silica
by Mykola I. Arabadzhy, Vyacheslav P. Pashkevych, Olena O. Pariiska, Oleksiy V. Melnychenko, Volodymyr V. Buryanov, Vladyslav V. Subotin, Bohdan V. Vashchenko, Eugeniy M. Ostapchuk, Andriy I. Frolov, Konstantin S. Gavrilenko, Serhiy V. Ryabukhin, Dmytro M. Volochnyuk and Sergey V. Kolotilov
Chemistry 2025, 7(1), 26; https://doi.org/10.3390/chemistry7010026 - 19 Feb 2025
Viewed by 251
Abstract
This study was aimed at elucidating the role of the carboneous component in Co–carbon-containing catalysts for the hydrogenation of organic compounds. A Co-C/SiO2 catalyst was synthesized via pyrolysis of a Co(II) complex with 1,2-diaminobenzene on silica and subsequently irradiated with 2.3 MeV [...] Read more.
This study was aimed at elucidating the role of the carboneous component in Co–carbon-containing catalysts for the hydrogenation of organic compounds. A Co-C/SiO2 catalyst was synthesized via pyrolysis of a Co(II) complex with 1,2-diaminobenzene on silica and subsequently irradiated with 2.3 MeV electrons, producing Co-C/SiO2*. A comprehensive characterization using XRD, TEM, IR, and Raman spectroscopy indicated minimal structural changes in the cobalt nanoparticles and carboneous materials. However, the Raman analysis revealed a slight decrease in the structural defect content in the carboneous component upon irradiation, which could occur due to defect healing. The catalytic tests, including the hydrogenation of 26 compounds, demonstrated an enhanced performance of the irradiated catalyst in 17 cases. This performance improvement was attributed to a modification of the carboneous material. It could be concluded that the carboneous components in Co-C composites contributed to their catalytic performance, probably by modifying the electronic structure of Co nanoparticles. In turn, the results provide arguments against the supposition that hydrogenation occurs on the structural defects of the carboneous material. Full article
(This article belongs to the Section Catalysis)
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17 pages, 2267 KiB  
Article
Simulating Analyte Extraction via Sorption in Powdered and Lyophilized Pharmaceutical Products Using Butyl Rubbers
by Nikolaos Kritikos, Anna Bletsou, Constantinos Kousoulos and Yannis Dotsikas
Chemistry 2025, 7(1), 25; https://doi.org/10.3390/chemistry7010025 - 18 Feb 2025
Viewed by 241
Abstract
A novel extraction method based on solid-to-solid interactions has been developed to investigate the acquisition of contaminants from butyl rubber materials, with potential applications in the pharmaceutical industry. The extraction medium used is silica gel—a cost-effective, non-toxic, heat-resistant, and chemically inert material that [...] Read more.
A novel extraction method based on solid-to-solid interactions has been developed to investigate the acquisition of contaminants from butyl rubber materials, with potential applications in the pharmaceutical industry. The extraction medium used is silica gel—a cost-effective, non-toxic, heat-resistant, and chemically inert material that is easy to handle in laboratory settings. Silica gel also enables straightforward recovery of adsorbed species using standard laboratory solvents. This method effectively exhausts contaminants from typical rubber articles within a reasonable timeframe, even under ambient conditions, while preserving the integrity of the material. Unlike traditional destructive liquid-based extractions, this approach produces significantly cleaner chromatographic profiles. This study focuses on the primary analytes extracted from chlorobutyl rubber, including halogenated rubber volatile impurities (VOIs), and tracks their acquisition over the course of the experiment. The findings provide valuable insights into the diffusion-based process by which pharmaceutical powders acquire contaminants, spanning a wide range of volatility and lipophilicity. Full article
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18 pages, 1166 KiB  
Article
Chemical and Biological Investigation of Ceiba chodatii Hassl. Flowers
by Engy Saadalah Ibrahem, John Refaat Fahim, Mamdouh Nabil Samy, Ahmed G. Darwish, Samar Yehia Desoukey, Mohamed Salah Kamel and Samir A. Ross
Chemistry 2025, 7(1), 24; https://doi.org/10.3390/chemistry7010024 - 12 Feb 2025
Viewed by 450
Abstract
Ceiba (syn. Chorisia) trees have attracted multifaceted attention not only due to their ornamental and economic value but also for their remarkable metabolic diversity and therapeutic properties. In view of that, this work explores the chemical composition of Ceiba chodatii Hassl. and [...] Read more.
Ceiba (syn. Chorisia) trees have attracted multifaceted attention not only due to their ornamental and economic value but also for their remarkable metabolic diversity and therapeutic properties. In view of that, this work explores the chemical composition of Ceiba chodatii Hassl. and its biological potential. Overall, GC–MS-based analysis of the lipoidal constituents of C. chodatii flowers revealed the presence of diverse classes of metabolites that were dominated by long-chain aliphatic esters (77.016%), ketones (6.396%), aliphatic hydrocarbons (5.757%), fatty alcohols (3.718%), aromatic acid esters (2.794%), alkylamides (1.58%), aldehydes (1.035%), aromatic hydrocarbons (0.31%), and ethers (0.29%). In addition, repeated chromatographic fractionation of different fractions of the total alcoholic extract of the flowers afforded 13 metabolites of varied structural types, including fatty esters and alcohols, phytosterols, monoglycerides, furanoids, and flavonoid glycosides. Structures of the obtained compounds were determined by different spectroscopic techniques, such as 1H- and 13C-NMR, APT, DEPT, and EI–MS analyses. Noteworthily, a wide range of the metabolites identified herein using different analytical approaches were described for the first time in the plant species under study or in those belonging to the genus Ceiba. Finally, the total extract and different fractions of C. chodatii flowers as well as the isolated flavonoids showed weak anti-infective potential against a group of human pathogens at concentration ranges up to 200 and 20 µg/mL, respectively. In contrast, the total extract and different fractions of the flowers exerted mild to moderate anti-proliferative activities against MDA-MB-468 cells, with IC50 in the range of 21.69–47.60 μg/mL. Full article
(This article belongs to the Section Biological and Natural Products)
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12 pages, 4907 KiB  
Article
Brazilian Plume (Justicia carnea L.) Leaf Wine-Colored Extract for Natural Dyeing of Mordant-Functionalized Cellulosic Fabric: Color Strength, Coordinates, and Fastness
by Jamiu Mosebolatan Jabar, Olugbenga Oludayo Oluwasina, Odunayo Michael Agunloye, Afolabi Clement Akinmoladun, Olamide Abigael Akande, Elizabeth Toyin Ojo and Hannah Olubukola Olojuolawe
Chemistry 2025, 7(1), 23; https://doi.org/10.3390/chemistry7010023 - 8 Feb 2025
Viewed by 412
Abstract
Increasing awareness of protecting the environment from chemically aided naive ecosystem degradation has encouraged the use of eco-friendly (biomass) materials in industrial production globally. This study investigated the application of a natural wine-colored extract from Brazilian plume (BP) leaf, obtained through a microwave-assisted [...] Read more.
Increasing awareness of protecting the environment from chemically aided naive ecosystem degradation has encouraged the use of eco-friendly (biomass) materials in industrial production globally. This study investigated the application of a natural wine-colored extract from Brazilian plume (BP) leaf, obtained through a microwave-assisted modern aqueous extraction technique, for toxic-free dyeing of mordant-functionalized cotton fabric. Dyeing of mordanted cotton fabric was optimized by varying dyeing parameters, such as dyeing contact time (10 to 90 min), pH (1 to 11), liquor ratio (1:5 to 1:30), and temperature (30 to 90 °C). UV-visible and Fourier transform infrared spectroscopic analyses confirmed that the chemical constituents of the extract were not altered by microwave radiation. The desired color strength (K/S) and dye-uptake (Q) were obtained at a dyeing time of 50 min, a pH of 7, a liquor ratio of 1:20, and a dyeing temperature of 60 °C. Varieties of elegant shades with desired colorfastness were developed through the involvement of less-toxic electrolyte and herbal mordants as functionalizing agents. BP extract is established as a potential sustainable and ecological colorant for textile industrial application. Full article
(This article belongs to the Section Green and Environmental Chemistry)
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13 pages, 14910 KiB  
Article
Too Persistent to Resist: Aromaticity in 16e Osmapentalene Radicals Survives Regardless of Redox
by Shijie Pan, Jun Yan, Weitang Li, Zhigang Shuai and Jun Zhu
Chemistry 2025, 7(1), 22; https://doi.org/10.3390/chemistry7010022 - 8 Feb 2025
Viewed by 723
Abstract
As one of the most important concepts in organic chemistry, aromaticity has attracted considerable attention from both theoretical and experimental chemists. Limited by the traditional rules (Hückel’s rules and Baird’s rules), species can only achieve aromaticity in a single state (S0 or [...] Read more.
As one of the most important concepts in organic chemistry, aromaticity has attracted considerable attention from both theoretical and experimental chemists. Limited by the traditional rules (Hückel’s rules and Baird’s rules), species can only achieve aromaticity in a single state (S0 or T1) in most cases. In 2018, our group first reported 16 electron osmapentalene that showed aromaticity in both the S0 and T1 states, which is defined as adaptive aromaticity. In recent years, although adaptive aromatic compounds have been expanded, the adaptive aromatics containing metal-centered radical has not been reported. Here, we carry out density functional theory calculations to explore the aromaticity of the corresponding radicals based on osmapentalyne and osmapentalenes in their S0 states. It is found that the corresponding radicals of adaptive aromatic osmapentalene exhibit aromaticity regardless of the radicals formed by oxidation or reduction, supported by a series of aromaticity indices including ΔBL, NICS, AICD, EDDB, and ELF. In contrast, for the nonaromatic or antiaromatic compound in the T1 state, only its cationic radical shows aromaticity. Furthermore, the spin density localization on the metal center is the key factor for the radicals to achieve aromaticity. Full article
(This article belongs to the Special Issue Open-Shell Systems—a Memorial Issue Dedicated to Professor Masayoshi Nakano)
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10 pages, 2021 KiB  
Communication
Stable Fluorenyl Radicals Showing Tunable Doublet Emission
by Xudong Hou, Tingting Xu, Jun Zhu, Shaofei Wu and Jishan Wu
Chemistry 2025, 7(1), 21; https://doi.org/10.3390/chemistry7010021 - 7 Feb 2025
Viewed by 528
Abstract
Neutral organic radicals with intrinsic spin-allowed doublet emission have emerged as a promising class of luminescent materials, garnering significant research interest. However, the development of stable luminescent radicals with tunable emission remains challenging. Herein, we present the synthesis of a series of 9-(2,4,6-trichlorophenyl)-substituted [...] Read more.
Neutral organic radicals with intrinsic spin-allowed doublet emission have emerged as a promising class of luminescent materials, garnering significant research interest. However, the development of stable luminescent radicals with tunable emission remains challenging. Herein, we present the synthesis of a series of 9-(2,4,6-trichlorophenyl)-substituted fluorenyl radicals functionalized with various substituents at the 3,6-positions. These radicals exhibit enhanced stability through efficient spin delocalization and kinetic protection. Notably, they display red-shifted photoluminescence compared to traditional polychlorotriphenylmethyl radicals, with maximum emission wavelengths ranging from 679 nm to 744 nm. The mechanisms underlying the doublet emission, as well as their electrochemical properties, have been thoroughly investigated. Full article
(This article belongs to the Special Issue Open-Shell Systems—a Memorial Issue Dedicated to Professor Masayoshi Nakano)
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10 pages, 225 KiB  
Article
Determination of Bioactive Compounds and Antioxidant Capacity in Leaf and Pulp of Annona muricata
by Mario Alberto Ruiz-López, Belinda Vargas-Guerrero, J. de Jesús Vargas-Radillo, Efigenia Montalvo-González, Eduardo Salcedo-Pérez, Ramon Rodriguez-Macias, Carmen Magdalena Gurrola-Diaz, Pedro Macedonio García-López and Juan Carlos Pizano-Andrade
Chemistry 2025, 7(1), 20; https://doi.org/10.3390/chemistry7010020 - 4 Feb 2025
Viewed by 479
Abstract
This study focused on analyzing and comparing bioactive compounds, specifically phenolics, in the pulp and leaf of Annona muricata (soursop), a crop highly valued in Latin America for its culinary and traditional uses. Methanolic extractions of leaf and pulp were performed for phytochemical [...] Read more.
This study focused on analyzing and comparing bioactive compounds, specifically phenolics, in the pulp and leaf of Annona muricata (soursop), a crop highly valued in Latin America for its culinary and traditional uses. Methanolic extractions of leaf and pulp were performed for phytochemical screening, high-performance liquid chromatography (HPLC), and measurements of antioxidant capacity. The results confirmed the presence of 15 phenolic compounds in the leaf and 14 in the pulp; these included phenolic acids and flavonoids. Shikimic acid was the main component identified, constituting 85 mg/g of the dry leaf sample and 17.50 mg/g of the dry pulp. The antioxidant capacity was determined using DPPH and FRAP. The percentages of inhibition were 70.93 and 15.10 in the leaf and pulp, respectively. This work expands our knowledge about the compounds present in A. muricata, which may be partly responsible for the known benefits of this plant for human health and nutrition. Full article
(This article belongs to the Section Biological and Natural Products)
8 pages, 1001 KiB  
Article
Copper-Catalyzed Four-Component A3-Based Cascade Reaction: Facile Synthesis of 3-Oxetanone-Derived Spirocycles
by Rongkang Zhang, Liliang Huang, Aiguo Gu and Huangdi Feng
Chemistry 2025, 7(1), 19; https://doi.org/10.3390/chemistry7010019 - 4 Feb 2025
Viewed by 482
Abstract
3-Oxetanone-derived spirooxazolidines represent a class of building blocks for accessing diverse saturated heterocycles, but their synthetic methods remain unexplored. Herein, we demonstrate a highly atom-economic approach for the synthesis of diverse 3-oxetanone-derived N-propargyl spirooxazolidines via a CuBr2/TFA co-catalyzed four-component A [...] Read more.
3-Oxetanone-derived spirooxazolidines represent a class of building blocks for accessing diverse saturated heterocycles, but their synthetic methods remain unexplored. Herein, we demonstrate a highly atom-economic approach for the synthesis of diverse 3-oxetanone-derived N-propargyl spirooxazolidines via a CuBr2/TFA co-catalyzed four-component A3-based cascade reaction of a 1,2-amino alcohol, a 3-oxetanone, a formaldehyde, and an alkyne. This strategy is characterized by a wide substrate range and excellent chemoselectivity. In addition, the synthesized spirocycles could also be easily converted into other valuable compounds, facilitating potentially useful synthetic applications. Full article
(This article belongs to the Special Issue Oxygen-Containing Heterocyclic Compounds: Recent Advances in Chemistry)
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25 pages, 4457 KiB  
Article
Pyrrolizine- and Indolizine-Derived Spirooxindoles: Synthesis, Antibacterial Activity and Inverse Docking Analysis
by Pablo Romo, María del Pilar Crespo, Mauricio Barreto, María Elena Burbano, Melissa Mejia-Gutierrez, Jairo Quiroga and Rodrigo Abonia
Chemistry 2025, 7(1), 18; https://doi.org/10.3390/chemistry7010018 - 1 Feb 2025
Viewed by 726
Abstract
Spirooxindoles are a family of heterocyclic compounds which bear the oxindole nucleus in their structures, which have a considerable pharmaceutical potential and which have been linked to various drugs for the treatment of diverse diseases. In this work, a wide variety of spirooxindoles [...] Read more.
Spirooxindoles are a family of heterocyclic compounds which bear the oxindole nucleus in their structures, which have a considerable pharmaceutical potential and which have been linked to various drugs for the treatment of diverse diseases. In this work, a wide variety of spirooxindoles bearing a pyrrolizinic nucleus were obtained by a 1,3-dipolar cycloaddition reaction between substituted isatins, trans-3-benzoyl acrylic acid and L-proline. In this approach, the target products 9a–m were obtained in 40–86% yields under heating to reflux in methanol over 2 h. Similarly, spirooxindoles containing an indolizinic nucleus 11a–j were obtained in 45–69% yields by switching L-proline for pipecolic acid under heating to reflux in acetonitrile for 8 h. The antibacterial activity of the obtained products was evaluated against P. aeruginosa, K. pneumoniae, E. coli, S. aureus, and N. gonorrhoeae, also including an inverse docking analysis. Results show that 9f and 11i, were the most active compounds against S. aureus, while compounds 9d and 9m displayed the higher activity against N. gonorrhoeae. Inverse docking analysis showed that compounds 9b, 11a 11e, and 11i displayed high affinity to the target protein 6TYM and 7Q6S, which are involved in biological pathways of diverse cancer and Parkinson diseases. Full article
(This article belongs to the Section Medicinal Chemistry)
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22 pages, 13794 KiB  
Review
Noble Metal-Based Catalysts for Selective Oxidation of HMF to FDCA: Progress in Reaction Mechanism and Active Sites
by Yingshuo Guo, Yitong Zhao, Shiao Gao, Binhong Lv and Zhijie Wu
Chemistry 2025, 7(1), 17; https://doi.org/10.3390/chemistry7010017 - 1 Feb 2025
Viewed by 618
Abstract
5-hydroxymethylfurfural (HMF) is oxidized to 2,5-furandicarboxylic acid (FDCA), which serves as a sustainable alternative to the petrochemical derivative terephthalic acid as a polyester monomer. Currently, noble metal catalysts that combine high HMF conversion rates with FDCA selectivity have become one of the mainstream [...] Read more.
5-hydroxymethylfurfural (HMF) is oxidized to 2,5-furandicarboxylic acid (FDCA), which serves as a sustainable alternative to the petrochemical derivative terephthalic acid as a polyester monomer. Currently, noble metal catalysts that combine high HMF conversion rates with FDCA selectivity have become one of the mainstream catalytic systems for HMF oxidation. This paper summarizes and discusses the research progress on HMF oxidation to FDCA over different noble metal-based catalysts by combining DFT theoretical calculations, introducing various reaction pathways and mechanisms of HMF oxidation. It also analyzes the characteristics and electronic properties of metal active sites, geometric effects, metal–support interactions, and confinement effects, discussing and revealing the roles and activation mechanisms of different metal active sites, the structure of catalysts, active substances, metal valence states, activity, and the relationship between metal and the oxidation of C=O and OH groups. Finally, it presents views on the challenges and future development in the design of noble metal-based catalysts. Full article
(This article belongs to the Special Issue Catalytic Conversion of Biomass and Its Derivatives)
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10 pages, 240 KiB  
Review
Nuclear Magnetic Resonance Gas-Phase Studies of Spin-Spin Couplings in Molecules
by Karol Jackowski
Chemistry 2025, 7(1), 16; https://doi.org/10.3390/chemistry7010016 - 26 Jan 2025
Viewed by 516
Abstract
This paper overviews gas phase experiments with respect to one fundamental part of nuclear magnetic resonance (NMR) spectra. Indirect spin-spin coupling is an important parameter of NMR spectra and is observed as the splitting of spectral signals. A molecule containing two different magnetic [...] Read more.
This paper overviews gas phase experiments with respect to one fundamental part of nuclear magnetic resonance (NMR) spectra. Indirect spin-spin coupling is an important parameter of NMR spectra and is observed as the splitting of spectral signals. A molecule containing two different magnetic nuclei (e.g., hydrogen HD, HT, or DT) exhibits this interaction in an external magnetic field measured as the spin-spin coupling parameter, nJ(NN′). Modern quantum chemical methods allow the precise calculation of spin-spin coupling, but it is never easy because nJ(NN′) is modified by temperature and intermolecular interactions. Accurate calculations can be performed only for small isolated molecules. NMR spectroscopy can deliver measurements of spin-spin couplings for isolated molecules if nJ(NN′) parameters are observed in the gas phase as a function of density. The extrapolation of such measurements to the zero-density limit permits nJ0(NN′) determination free from intermolecular interactions. The latter technique can also be applied to liquid vapors in molecules like acetonitrile or water. Spin-spin couplings across one chemical bond (1J0(NN′)) are the largest and most important for theoretical modeling. The present review reports numerous 1J0(NN′) parameters recently measured by multinuclear NMR spectra of gaseous samples. Full article
(This article belongs to the Section Physical Chemistry and Chemical Physics)
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13 pages, 4484 KiB  
Article
Synthesis and Characterization of Quinoxaline-Fused Cyclopenta[cd]azulene
by Tomohiro Oda, Yuina Onishi, Akihito Konishi and Makoto Yasuda
Chemistry 2025, 7(1), 15; https://doi.org/10.3390/chemistry7010015 - 23 Jan 2025
Viewed by 1065
Abstract
Azulene-based polycyclic hydrocarbons have garnered much attention as potential materials for organic optoelectronic devices and as molecular models for graphene nanosheets with structural defects. Although various methods for ring fusions to an azulene core have been established for ring fusions to an azulene [...] Read more.
Azulene-based polycyclic hydrocarbons have garnered much attention as potential materials for organic optoelectronic devices and as molecular models for graphene nanosheets with structural defects. Although various methods for ring fusions to an azulene core have been established for ring fusions to an azulene core, efficient synthetic methodologies for ortho- and peri-fusion to an azulene core are still lacking, which hinders the investigation of the effect of the ortho- and peri-fusion on the electronic properties of the embedded azulene core. Herein, we describe the synthesis and characterization of quinoxaline-fused cyclopenta[cd]azulene 4 as a new ortho- and peri-fused azulene derivative. The target molecule 4 was successfully synthesized in four steps from 4-methylazulene. The ring annulation decreased the lowest excitation energy compared with that of azulene and its structural isomer 5 and led to multiple reversible reduction processes. Characterization of the molecular geometry and optoelectronic properties of 4 revealed that the embedded azulene core preserves its original aromaticity, while the fused quinoxaline acts as a nucleophilic and basic site. These features suggest that 4 could serve as a metal ligand, a near-infrared absorber, and a component in organic functional devices. Full article
(This article belongs to the Special Issue Open-Shell Systems—a Memorial Issue Dedicated to Professor Masayoshi Nakano)
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16 pages, 2317 KiB  
Article
Development and Validation of an HPLC-FLD Method for the Determination of Pyridoxine and Melatonin in Chocolate Formulations—Digestion Simulation Study
by Georgios Kamaris, Vasiliki-Panagiota M. Mitsiou, Konstantina Chachlioutaki, Sofia Almpani and Catherine K. Markopoulou
Chemistry 2025, 7(1), 14; https://doi.org/10.3390/chemistry7010014 - 23 Jan 2025
Viewed by 692
Abstract
The undeniable value of sleep is commonly accepted and essential for all aspects of human existence. The aim of the present study was to develop and validate an applicable and sensitive HPLC-FLD method for the quantitative determination of pyridoxine (PYR) and melatonin (MEL) [...] Read more.
The undeniable value of sleep is commonly accepted and essential for all aspects of human existence. The aim of the present study was to develop and validate an applicable and sensitive HPLC-FLD method for the quantitative determination of pyridoxine (PYR) and melatonin (MEL) in a chocolate formulation that is suitable for the treatment of insomnia. The proposed chromatographic process was performed on an Aqua column (250 mm × 4.6 mm, 5 mm) at 45 °C, with a mobile phase consisting of two solvents (A, water with 0.2% formic acid; and B, acetonitrile with 0.2% formic acid) in a gradient elution and with a flow rate of 1.2 mL/min. Method validation was carried out according to ICH specifications in terms of linearity (R2 > 0.999), precision, and repeatability (%RSD < 2). The limits of detection (LODs: PYR = 0.09 ng/mL; MEL = 0.92 ng/mL) and quantification (LOQs: PYR = 0.29 ng/mL; LOQMEL = 3.04 ng/mL) for both analytes were also determined. A mixture D-Optimal methodology of experimental design technique was applied for the quantitative recovery of the two APIs from chocolate (% recovery > 97.4%). Finally, to simulate the digestion process of the new preparation, three phases in vitro, a digestion method was applied. According to the study, 73.8% of pyridoxine and 55.9% of melatonin (on the indicated dose) were released from the formulation and ended up in the intestine. Full article
(This article belongs to the Section Medicinal Chemistry)
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11 pages, 2105 KiB  
Article
Nitrogen-Doped MXene Electrodes for High-Voltage Window Supercapacitors in Organic Electrolytes
by Yingyi Liao, Xiaoqing Bin, Jing Xu, Xuedong He and Wenxiu Que
Chemistry 2025, 7(1), 13; https://doi.org/10.3390/chemistry7010013 - 23 Jan 2025
Viewed by 519
Abstract
MXene has excellent electrochemical performance in aqueous electrolytes; however, its narrow voltage window (hydrolysis voltage ≤ 1.2 V) limits the energy density of supercapacitors. Compared to conventional aqueous electrolytes, ionic liquid (IL) electrolytes exhibit a much larger voltage window, but their larger ion [...] Read more.
MXene has excellent electrochemical performance in aqueous electrolytes; however, its narrow voltage window (hydrolysis voltage ≤ 1.2 V) limits the energy density of supercapacitors. Compared to conventional aqueous electrolytes, ionic liquid (IL) electrolytes exhibit a much larger voltage window, but their larger ion size limits the transport and intercalation of IL cations in MXene electrodes. Therefore, the electrochemical performances for three different types of organic electrolytes based on nitrogen-doped MXene electrodes in supercapacitors were investigated, with the voltage windows of the devices effectively widened to 2.4 V. In addition, the nitrogen-doped MXene electrodes also effectively adjusted the interlayer spacing of the MXene nanosheets, with the enlarged interlayer spacing (from 12.60 Å to 14.24 Å) being more favorable for the intercalation and de-intercalation of larger-sized organic ions within the electrodes, thus effectively storing a charge. Among them, the 1 M EMIMTFSI/LiTFSI/ACN electrolyte is optimal due to the introduction of a smaller ion size for Li+, and so the corresponding supercapacitor achieves the electrode capacitance of up to 147 F g−1, with the maximum energy density of 29.4 Wh kg−1. This work provides a new strategy for reasonably optimizing the design of organic electrolytes matching modified MXene electrodes to effectively enhance the energy density of supercapacitors. Full article
(This article belongs to the Section Electrochemistry and Photoredox Processes)
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12 pages, 1727 KiB  
Article
Tethered Antigenic Suppression Shields the Hemagglutinin Head Domain and Refocuses the Antibody Response to the Stalk Domain
by Donguk Kim, Kathryn Loeffler, Yixin Hu, Ammar Arsiwala, Steven Frey, Shruthi Murali, Vivek Hariharan, Alberto Moreno and Ravi S. Kane
Chemistry 2025, 7(1), 12; https://doi.org/10.3390/chemistry7010012 - 21 Jan 2025
Viewed by 701
Abstract
Influenza has been a global health concern for the past century. Current seasonal influenza vaccines primarily elicit an antibody response that targets the immunodominant head domain of the viral glycoprotein hemagglutinin (HA), which consistently mutates due to selective pressure. To circumvent this problem, [...] Read more.
Influenza has been a global health concern for the past century. Current seasonal influenza vaccines primarily elicit an antibody response that targets the immunodominant head domain of the viral glycoprotein hemagglutinin (HA), which consistently mutates due to selective pressure. To circumvent this problem, we introduce a “tethered antigenic suppression” strategy to shield the HA head domain and refocus the immune response towards the conserved but immunosubdominant stalk domain of HA. Specifically, we tethered an antibody fragment (Fab) that recognizes the Sb antigenic site in the HA head domain to the HA protein with a linker. We immunized separate groups of female mice with the Fab-tethered HA or regular HA and characterized the elicited antibody response. We demonstrate that shielding the HA head domain with a tethered Fab suppresses the antibody titers towards all five key antigenic sites in the HA head domain while eliciting a robust anti-stalk antibody response. Our work highlights the potential of tethered antigenic suppression as a strategy to refocus the antibody response towards conserved epitopes on protein antigens. Full article
(This article belongs to the Special Issue A Themed Issue in Honor of Professor George Whitesides on the Occasion of His 85th Birthday Anniversary)
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28 pages, 1219 KiB  
Review
Chemometric Approaches for Sustainable Pharmaceutical Analysis Using Liquid Chromatography
by Dina Aboushady, Liza Samir, Alaa Masoud, Yasmin Elshoura, Abdelgawad Mohamed, Rasha S. Hanafi and Sami El Deeb
Chemistry 2025, 7(1), 11; https://doi.org/10.3390/chemistry7010011 - 20 Jan 2025
Viewed by 1038
Abstract
Chemometrics, which applies mathematical and statistical methods to aid in experimental design, data analysis, and process optimization, is gaining more importance. It plays an important role in enhancing the sustainability of analytical methods when integrated with green analytical chemistry. Applying chemometrics to liquid [...] Read more.
Chemometrics, which applies mathematical and statistical methods to aid in experimental design, data analysis, and process optimization, is gaining more importance. It plays an important role in enhancing the sustainability of analytical methods when integrated with green analytical chemistry. Applying chemometrics to liquid chromatographic methods can speed up the analytical method, saving time, energy, and solvent consumption. This would be reflected by a low energy footprint and environmental impact. This review discusses the application of chemometric methods like multivariant data analysis, design of experiments, retention time prediction, and peak deconvolution in green liquid chromatographic analysis of pharmaceuticals. The review highlights the impact of chemometric approaches on the global push for sustainable practices. The integration of chemometrics into sustainable chromatographic analysis will continue to revolutionize the field leading to better performance of analytical methods. Full article
(This article belongs to the Section Medicinal Chemistry)
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19 pages, 1295 KiB  
Article
Dielectrically Monitored Flow Synthesis of Functional Vaccine Adjuvant Mixtures via Microwave-Assisted Catalytic Chain Transfer Processing
by Cordula S. Hege, Ian E. Hamilton, Adam A. Dundas, Kevin Adlington, Edward Walker, Helena Henke, Kaiyang Wang, Georgios Dimitrakis, Adam Buttress, Christopher Dodds, Christopher B. Fox and Derek J. Irvine
Chemistry 2025, 7(1), 10; https://doi.org/10.3390/chemistry7010010 - 17 Jan 2025
Viewed by 590
Abstract
A novel flow process to produce low-molecular-weight (Mwt) methacrylate oligomer mixtures that have potential as vaccine adjuvants and chain transfer agents (CTAs) is reported. The chemistry and process were designed to significantly reduce the number of stages required to manufacture methyl methacrylate oligomer-in-monomer [...] Read more.
A novel flow process to produce low-molecular-weight (Mwt) methacrylate oligomer mixtures that have potential as vaccine adjuvants and chain transfer agents (CTAs) is reported. The chemistry and process were designed to significantly reduce the number of stages required to manufacture methyl methacrylate oligomer-in-monomer mixtures with an oligomer Mwt range of dimers to pentamers and >50% conversion. Combining rapid in-flow, in situ catalytic chain transfer polymerization catalyst synthesis and volumetric microwave heating of the reaction medium resulted in catalyst flow synthesis being completed in <4 min, removing the need to pre-synthesize it. The steady-state operation was then successfully maintained with very low levels of external energy, as the process utilized the reaction exotherm. The microwave process outperformed a comparative conventionally heated system by delivering a 20% increase in process throughput with no change in final product quality or conversion. Additionally, combining flow and in situ catalyst processing enabled the use of a more oxidatively unstable catalyst. This allowed for in situ catalyst deactivation post-generation of the oligomers, such that residual catalyst did not need to be removed prior to preparing subsequent vaccine adjuvant or CTA screening formulations. Finally, dielectric property measurements were able to monitor the onset of reaction and steady-state operation. Full article
(This article belongs to the Section Molecular Organics)
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14 pages, 2389 KiB  
Review
Prof. George Whitesides’ Contributions to Self-Assembled Monolayers (SAMs): Advancing Biointerface Science and Beyond
by Tomohiro Hayashi
Chemistry 2025, 7(1), 9; https://doi.org/10.3390/chemistry7010009 - 16 Jan 2025
Viewed by 949
Abstract
Prof. George Whitesides’ pioneering contributions to the field of self-assembled monolayers (SAMs) have profoundly influenced biointerface science and beyond. This review explores the development of SAMs as highly organized molecular structures, focusing on their role in advancing surface science, biointerface research, and biomedical [...] Read more.
Prof. George Whitesides’ pioneering contributions to the field of self-assembled monolayers (SAMs) have profoundly influenced biointerface science and beyond. This review explores the development of SAMs as highly organized molecular structures, focusing on their role in advancing surface science, biointerface research, and biomedical applications. Prof. Whitesides’ systematic investigations into the effects of SAMs’ terminal group chemistries on protein adsorption and cell behavior culminated in formulating “Whitesides’ Rules”, which provide essential guidelines for designing bioinert surfaces. These principles have driven innovations in anti-fouling coatings for medical devices, diagnostics, and other biotechnological applications. We also discuss the critical role of interfacial water in SAM bioinertness, with studies demonstrating its function as a physical barrier preventing protein and cell adhesion. Furthermore, this review highlights how data science and machine learning have expanded the scope of SAM research, enabling predictive models for bioinert surface design. Remarkably, Whitesides’ Rules have proven applicable not only to SAMs but also to polymer-brush films, illustrating their broad relevance. Prof. Whitesides’ work provides a framework for interdisciplinary advancements in material science, bioengineering, and beyond. The enduring legacy of his contributions continues to inspire innovative approaches to addressing challenges in biomedicine and biotechnology. Full article
(This article belongs to the Special Issue A Themed Issue in Honor of Professor George Whitesides on the Occasion of His 85th Birthday Anniversary)
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12 pages, 773 KiB  
Article
Survey of Aconitum Alkaloids to Establish an Aconitum carmichaeli (Fu-Zi) Processing Procedure and Quality Index
by Kun-Teng Wang, Ming-Chung Lee and Wu-Chang Chuang
Chemistry 2025, 7(1), 8; https://doi.org/10.3390/chemistry7010008 - 14 Jan 2025
Viewed by 641
Abstract
Processed Fu-Zi (the lateral roots of Aconitum carmichaeli) is beneficial for the cardiac system, but, because it contains toxins, raw Fu-Zi produces arrhythmia and breathing difficulties. C19 diester diterpenoid alkaloids (DDAs), including aconitine, mesaconitine, and hypaconitine, are toxic Aconitum alkaloids found [...] Read more.
Processed Fu-Zi (the lateral roots of Aconitum carmichaeli) is beneficial for the cardiac system, but, because it contains toxins, raw Fu-Zi produces arrhythmia and breathing difficulties. C19 diester diterpenoid alkaloids (DDAs), including aconitine, mesaconitine, and hypaconitine, are toxic Aconitum alkaloids found in Fu-Zi and can be hydrolyzed to nontoxic monoester diterpenoid alkaloids (MDAs), including benzoylaconine, benzoylmesaconine, and benzoylhypaconine. In this study, six processed Fu-Zi decoction pieces and herbal medicines were analyzed. The highest DDA contents were found in Shengfupian, the raw Fu-Zi samples. A processing quality index (Grades A to D) was established to evaluate the processing quality of Fu-Zi. The data demonstrated that few Fu-Zi decoction pieces did not conform to the government regulation. The results of testing the inorganic elements showed that the calcium content increased by approximately 5 to 30 fold compared to raw Fu-Zi due to substances assisting with processing. Raw Fu-Zi processed by boiling, without additional substances, may have a decreased DDA content. This study provides a method of determining the quality status of pieces of Fu-Zi decoction and establishes a processing quality index for pieces of Fu-Zi decoction and herbal medicine. Furthermore, our results suggest that it is not necessary to use additional substance to assist with the processing of Fu-Zi. Through the established processing quality index, Fu-Zi may be used more safely and may demonstrate a greater consistency in quality. Full article
(This article belongs to the Section Biological and Natural Products)
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37 pages, 8429 KiB  
Review
Chemical Space of Fluorinated Nucleosides/Nucleotides in Biomedical Research and Anticancer Drug Discovery
by Yugandhar Kothapalli, Tucker A. Lesperance, Ransom A. Jones, Chung K. Chu and Uma S. Singh
Chemistry 2025, 7(1), 7; https://doi.org/10.3390/chemistry7010007 - 13 Jan 2025
Viewed by 925
Abstract
Fluorinated nucleos(t)ide drugs have proven to be successful chemotherapeutic agents in treating various cancers. The Food and Drug Administration (FDA) has approved several drugs that fit within the fluorinated nucleoside pharmacophore, and many more are either in preclinical development or clinical trials. The [...] Read more.
Fluorinated nucleos(t)ide drugs have proven to be successful chemotherapeutic agents in treating various cancers. The Food and Drug Administration (FDA) has approved several drugs that fit within the fluorinated nucleoside pharmacophore, and many more are either in preclinical development or clinical trials. The addition of fluorine atoms to nucleos(t)ides improves the metabolic stability of the glycosidic bond and, in certain instances, facilitates additional interactions of nucleons(t)ides with receptors. The insertion of fluorine either on sugar or the base of nucleos(t)ides proved to enhance the lipophilicity, pharmacokinetic, and pharmacodynamic properties. Overall, the fluorine atom feeds diverse advantages to the biological profile of nucleos(t)ide analogs by improving their drug-like properties and therapeutic potential. This review article covers the often-used fluorinating reagents in nucleoside chemistry, the clinical significance of [18F]-labeled nucleosides, the synthesis and anticancer activity of FDA-approved fluoro-nucleos(t)ide drugs, as well as clinical candidates, which are at various stages of clinical development as anticancer agents. Full article
(This article belongs to the Section Medicinal Chemistry)
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11 pages, 1997 KiB  
Article
Expanding the Chemical Diversity of Stemona parviflora: Isolation and Characterization of New Parvistemoline-Type Alkaloids
by Shuaizhen Zhou, Ruolin Geng, Changqiang Ke, Fan Ge, Ying Chen, Chunping Tang and Yang Ye
Chemistry 2025, 7(1), 6; https://doi.org/10.3390/chemistry7010006 - 13 Jan 2025
Viewed by 446
Abstract
A comprehensive phytochemical investigation of the whole plant of Stemona parviflora led to the isolation of 13 alkaloidal constituents, including five new alkaloids, parvistemonines B–F (1–5). The structures of these compounds were elucidated through extensive analyses of 1D and [...] Read more.
A comprehensive phytochemical investigation of the whole plant of Stemona parviflora led to the isolation of 13 alkaloidal constituents, including five new alkaloids, parvistemonines B–F (1–5). The structures of these compounds were elucidated through extensive analyses of 1D and 2D NMR spectra, DFT NMR calculation, and comparisons with data in the literature. Notably, compounds 1–4 represent new examples of the rare parvistemoline-type alkaloids, with compound 4 showcasing a unique rearranged skeleton. Additionally, parvistemonine F (5) was identified as a distinct alkaloid skeleton characterized by a n-butyl side chain. These findings significantly expand our understanding of the chemical diversity of parvistemoline-type alkaloids and provide clues for elucidating the biosynthetic pathways of these structurally unique parvistemoline alkaloids. Full article
(This article belongs to the Section Biological and Natural Products)
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11 pages, 3570 KiB  
Article
Starting Electroosmosis in a Fibrous Porous Medium with Arbitrary Electric Double-Layer Thickness
by Wei Z. Chen and Huan J. Keh
Chemistry 2025, 7(1), 5; https://doi.org/10.3390/chemistry7010005 - 8 Jan 2025
Viewed by 623
Abstract
The transient electroosmotic response in a charged porous medium consisting of a uniform array of parallel circular cylindrical fibers with arbitrary electric double layers filled with an electrolyte solution, for the stepwise application of a transverse electric field, is analyzed. The fluid momentum [...] Read more.
The transient electroosmotic response in a charged porous medium consisting of a uniform array of parallel circular cylindrical fibers with arbitrary electric double layers filled with an electrolyte solution, for the stepwise application of a transverse electric field, is analyzed. The fluid momentum conservation equation is solved for each cell by using a unit cell model, where a single cylinder is surrounded by a coaxial shell of the electrolyte solution. A closed-form expression for the transient electroosmotic velocity of the bulk fluid in the Laplace transform is obtained as a function of the ratio of the cylinder radius to the Debye screening length and the porosity of the fiber matrix. The effect of the fiber matrix porosity on the continuous growth of the electroosmotic velocity over time is substantial and complicated. For a fiber matrix with larger porosity, the bulk fluid velocity takes longer to reach a certain percentage of its final value. Although the final value of the bulk fluid velocity generally increases with increasing porosity, early velocities may decrease with increasing porosity. For a given fiber matrix porosity, the transient electroosmotic velocity is a monotonically increasing function of the ratio of the cylinder radius to the Debye length. Full article
(This article belongs to the Section Physical Chemistry and Chemical Physics)
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12 pages, 1468 KiB  
Article
Comprehensive Chemical Analysis of Codonopsis lanceolata Roots Using Ultra-High-Performance Liquid Chromatography–Quadrupole-Exactive–Orbitrap Mass Spectrometry
by Chang Luo, Zenan Duan, Takashi Kikuchi, Kouharu Otsuki, Mi Zhang, Ryuichi Kambayashi, Katsuhiko Ito, Atsushi Sugiyama and Wei Li
Chemistry 2025, 7(1), 4; https://doi.org/10.3390/chemistry7010004 - 6 Jan 2025
Viewed by 656
Abstract
The roots of Codonopsis lanceolata (Siebold & Zucc.) Benth. & Hook.f. ex Trautv. have been traditionally used for medicinal purposes across East Asia. However, their chemical constituents in Japanese-grown varieties remain uninvestigated. This study employed ultra-high-performance liquid chromatography–quadrupole–orbitrap mass spectrometry to perform a [...] Read more.
The roots of Codonopsis lanceolata (Siebold & Zucc.) Benth. & Hook.f. ex Trautv. have been traditionally used for medicinal purposes across East Asia. However, their chemical constituents in Japanese-grown varieties remain uninvestigated. This study employed ultra-high-performance liquid chromatography–quadrupole–orbitrap mass spectrometry to perform a comprehensive chemical analysis of the roots of C. lanceolata cultivated in Nagano Prefecture, Japan, leveraging fragment pattern analysis of both isolated and commercially available compounds as references compounds. As a result, 27 compounds, including triterpenoid saponins (19–22), polyacetylenes (6, 15, 18), flavonoids (16, 17), phenylpropanoids (3–5, 7, 9), a lignan (10), glycolipids (8, 11–14), phospholipids (23–27), and amino acids (1, 2), were identified. Notably, a triterpenoid saponin (19) was identified as a previously unreported compound, and ten compounds (3, 6, 8, 10, 13, 17, and 23–27) were identified from C. lanceolata roots for the first time. The ex vivo study revealed that lancemaside A (22) exhibited a time-dependent vasodilatory effect on rat aortic ring specimens. These findings not only advanced the understanding of the chemical constituents and biological activity of C. lanceolata roots but also provided valuable insights for their future applications and quality control. Full article
(This article belongs to the Section Biological and Natural Products)
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15 pages, 9586 KiB  
Article
Zeolite Synthesized from Solid Waste for Eco-System Remediation: Selective Adsorption in Wastewater
by Mariana S. Araujo, Danilo Costa-Silva, Juliana C. Izidoro, Denise A. Fungaro and Sonia Mello Castanho
Chemistry 2025, 7(1), 3; https://doi.org/10.3390/chemistry7010003 - 31 Dec 2024
Viewed by 718
Abstract
The present investigation explores the potential of two synthesized zeolites, derived from coal fly ash (CFA; thermoelectric waste) and sugarcane bagasse ash (SCBA; agro-industrial waste), for the selective adsorption of cesium in wastewater. The synthesized zeolites (ZCFA and ZSCBA) were characterized and compared [...] Read more.
The present investigation explores the potential of two synthesized zeolites, derived from coal fly ash (CFA; thermoelectric waste) and sugarcane bagasse ash (SCBA; agro-industrial waste), for the selective adsorption of cesium in wastewater. The synthesized zeolites (ZCFA and ZSCBA) were characterized and compared with a commercial zeolite to evaluate their physicochemical properties and effectiveness in removing cesium ions (Cs+) from simulated radioactive wastewater. The results obtained from X-ray diffraction, scanning electron microscopy, and elemental analysis confirmed the successful synthesis of high-purity zeolite from both solid wastes. The impurities present in the ashes impacted the Si/Al ratio and consequently influenced the exchange capacity. After adsorption experiments, neutron activation analysis (NAA) revealed that ZSCBA adsorbed 33.4% of Cs2O by weight, outperforming both ZCFA (26.0%) and commercial zeolite (27.9%). The superior performance of ZSCBA is attributed to its distinct Si/Al ratio and lower levels of impurities, highlighting the impact of these factors on adsorption selectivity. The findings in this study demonstrate the feasibility of valorizing agro-industrial waste for synthesizing zeolites, offering a sustainable approach for managing these residues while producing valuable materials for environmental remediation. Full article
(This article belongs to the Section Chemistry of Materials)
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17 pages, 4918 KiB  
Article
Mechanistic Insights into Sugar Racemization and Oxidative Degradation via Fenton and Alkaline Peroxide Systems
by Zoltán Köntös and Áron Németh
Chemistry 2025, 7(1), 2; https://doi.org/10.3390/chemistry7010002 - 26 Dec 2024
Viewed by 634
Abstract
This study explores the oxidation and racemization of selected C5 and C6 sugars using hydrogen peroxide (H2O2) in alkaline and Fenton reaction conditions. The sugars studied include D-Glucose, D-Fructose, D-Mannose, D-Xylose, D-Lactose, D-Arabinose, D-Cellobiose, Sucrose, and D-Galactose. Oxidation reactions [...] Read more.
This study explores the oxidation and racemization of selected C5 and C6 sugars using hydrogen peroxide (H2O2) in alkaline and Fenton reaction conditions. The sugars studied include D-Glucose, D-Fructose, D-Mannose, D-Xylose, D-Lactose, D-Arabinose, D-Cellobiose, Sucrose, and D-Galactose. Oxidation reactions were conducted using both Fenton’s reagent and NaOH/H2O2 to examine product formation, yield distribution, and stereochemical transformations. Under alkaline conditions, sugars primarily oxidized to yield sodium formate and hydrogen, with the minimal formation of intermediate sugar acids. Excess alkaline conditions further promoted the rapid degradation of sugars to sodium formate and hydrogen as primary products, indicating the strong influence of reaction conditions on oxidation pathways. A significant observation was that both alkaline and Fenton oxidation led to racemization, converting optically pure sugars into a racemic mixture of D- and L-enantiomers, thus producing products with zero optical rotation. The generation of L-enantiomers, metabolically inactive in biological systems, has implications for energy yield and biochemical efficiency. Full article
(This article belongs to the Section Theoretical and Computational Chemistry)
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20 pages, 5266 KiB  
Article
Synthesis of Spherical and Layered Ag-SiO2-TiO2/TiO2-Ag Structures
by Aleksander A. Buzaev, Valerya A. Tkachuk, Alexandra M. Zakharkiva and Lyudmila P. Borilo
Chemistry 2025, 7(1), 1; https://doi.org/10.3390/chemistry7010001 - 25 Dec 2024
Viewed by 509
Abstract
Due to the unique properties of titanium dioxide (TiO2), titanium oxide catalysts hold significant potential for photo-oxidative processes involving organic substances in liquid media. The current research has focused on developing new preparation methods that enable the manipulation of the properties, [...] Read more.
Due to the unique properties of titanium dioxide (TiO2), titanium oxide catalysts hold significant potential for photo-oxidative processes involving organic substances in liquid media. The current research has focused on developing new preparation methods that enable the manipulation of the properties, structure, and geometric shape of catalysts to enhance their efficiency in targeted reactions. This study developed a method for preparing Ag-SiO2-TiO2/TiO2-Ag layered structures with a spherical shape, featuring particle diameters ranging from 232 to 653 μm and mesopores of 2–20 nm. This was achieved by combining sol–gel and template synthesis methods. A comprehensive analysis of the obtained materials was conducted using methods such as X-ray phase analysis, micro-X-ray spectral analysis, X-ray microanalysis, and scanning electron spectroscopy. The photocatalytic properties were assessed by measuring the degree of decomposition of methyl orange in a model oxidation reaction under light radiation. The obtained spherical Ag-SiO2-TiO2/TiO2-Ag layered structures demonstrated high efficiency in the photooxidation of methyl orange in the model reaction. Full article
(This article belongs to the Section Catalysis)
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