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Keywords = tin(II)

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26 pages, 1672 KB  
Article
Synthesis and Microbiological Activities of 3-Nitropyrazolo-[1,5-d][1,2,4]triazin-7(6H)-ones and Derivatives
by Viktor A. Zapol’skii, Diana C. Munoz Castillo, Brigitte Pawletta, Ursula Bilitewski, Mimoza Gjikaj, Christoff Brüdigam and Dieter E. Kaufmann
Molecules 2025, 30(18), 3792; https://doi.org/10.3390/molecules30183792 - 18 Sep 2025
Viewed by 505
Abstract
A new synthetic strategy for pyrazolo[1,5-d][1,2,4]triazin-7(6H)-ones 4 through intramolecular cyclization of alkyl 2-(4-nitro-1H-pyrazol-3-yl)methylene)hydrazine-1-carboxylates 3 is described, allowing us to selectively modify the N-substituent in 3-position. The reduction in nitro compounds 4 with tin(II) chloride leads to [...] Read more.
A new synthetic strategy for pyrazolo[1,5-d][1,2,4]triazin-7(6H)-ones 4 through intramolecular cyclization of alkyl 2-(4-nitro-1H-pyrazol-3-yl)methylene)hydrazine-1-carboxylates 3 is described, allowing us to selectively modify the N-substituent in 3-position. The reduction in nitro compounds 4 with tin(II) chloride leads to amines 5, and their acetylation leads to acetamides 6. Via alkylation of 4 with bromoacetic acid alkyl esters and 2-chloro-5-(chloromethyl)pyridine, and the subsequent reduction in alkylated nitro compounds 7, the corresponding amines 8 and amides 9 were accessible in very good yields. The molecular structure of ethyl 2-(2-morpholino-3-nitro-7-oxopyrazolo[1,5-d][1,2,4]triazin-6(7H)-yl)acetate (7b) was confirmed by single-crystal X-Ray diffraction analysis. Antibacterial and cytotoxic properties were evaluated for 61 synthesized compounds. Full article
(This article belongs to the Section Organic Chemistry)
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16 pages, 5322 KB  
Article
One-Pot Synthesis of Silicone–Urethane Hybrid Foam and Comparison of Flame Retardant, Rheological, and Mechanical Properties with Polyurethane Foam
by Sosan Hwang, Hyeon Woo Jeong, Asell Kim, Tae Soon Kwan, Sun Kyoung Jeoung, Sung-Hyeon Baeck, Sang Eun Shim and Yingjie Qian
Polymers 2025, 17(17), 2352; https://doi.org/10.3390/polym17172352 - 29 Aug 2025
Viewed by 803
Abstract
This study presents the design and fabrication of silicone–urethane hybrid foam (SUF) to improve fire safety in transportation seating. Tin(II) 2-ethylhexanoate (Sn(OCT)2) was used to catalyze reactions between bifunctional isocyanates, polyols, and vinyl-terminated PDMS, enabling simultaneous curing and foaming. Sn(OCT)2 [...] Read more.
This study presents the design and fabrication of silicone–urethane hybrid foam (SUF) to improve fire safety in transportation seating. Tin(II) 2-ethylhexanoate (Sn(OCT)2) was used to catalyze reactions between bifunctional isocyanates, polyols, and vinyl-terminated PDMS, enabling simultaneous curing and foaming. Sn(OCT)2 effectively facilitated both the foaming and gelation processes of silicone and urethane chemistries. The resulting SUF demonstrated a 44.55% reduction in peak heat release rate (PHRR) compared to UF, due to the PDMS network’s synergistic flame-retardant and barrier effects. Additionally, the crosslinked PDMS structure maintained strong mechanical integrity. This study offers a simple and effective approach for producing SUF with enhanced fire safety. Full article
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25 pages, 5569 KB  
Article
Effect of Indium Doping on the Photoelectric Properties of SnS Thin Films and SnS/TiO2 Heterojunctions
by Jiahao Leng, Yaoxin Ding, Mingyang Zhang and Jie Shen
Coatings 2025, 15(8), 972; https://doi.org/10.3390/coatings15080972 - 20 Aug 2025
Viewed by 634
Abstract
This study addresses the need for efficient photoelectric materials by fabricating Indium-doped tin sulfide (SnS-In)/titanium dioxide (TiO2) heterostructure thin films via radio frequency (RF) magnetron sputtering. We systematically investigated the synergistic enhancement of photoelectric properties from both In-doping and the heterostructure [...] Read more.
This study addresses the need for efficient photoelectric materials by fabricating Indium-doped tin sulfide (SnS-In)/titanium dioxide (TiO2) heterostructure thin films via radio frequency (RF) magnetron sputtering. We systematically investigated the synergistic enhancement of photoelectric properties from both In-doping and the heterostructure design. SnS-In films with controlled In concentrations were prepared by embedding varying numbers of indium pellets into the SnS sputtering target. Our findings reveal that an optimal In doping of 4.93 at% significantly improves the crystalline quality and light absorption of SnS, reducing its band gap from 1.27 eV to 1.13 eV and enhancing carrier concentration and mobility. Subsequently, the optimized SnS-In film combined with TiO2 formed a heterojunction, achieving a peak photocurrent density of 6.36 µA/cm2 under visible light. This is 2.2 and 53.0 times higher than standalone SnS-In and TiO2 films, respectively. This superior performance is attributed to the optimal In3+ doping effectively modulating the SnS band structure and the type-II heterojunction promoting efficient charge separation. This work demonstrates a promising strategy for optoelectronic conversion and photocatalysis by combining In-doping for SnS band structure engineering with TiO2 heterostructure construction. Full article
(This article belongs to the Special Issue Electrochemical Properties and Applications of Thin Films)
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24 pages, 4914 KB  
Article
Research on the Production of Methyltrioxorhenium and Heterogenous Catalysts from Waste Materials
by Joanna Malarz, Karolina Goc, Mateusz Ciszewski, Karolina Pianowska, Patrycja Wróbel, Łukasz Hawełek, Dorota Kopyto and Katarzyna Leszczyńska-Sejda
Crystals 2025, 15(8), 717; https://doi.org/10.3390/cryst15080717 - 8 Aug 2025
Viewed by 660
Abstract
This paper presents the research results on the synthesis of rhenium catalysts MTO, Re2O7/Al2O3, and M-Re2O7/Al2O3 (where M = Ni, Ag, Co, Cu) from rhenium compounds (ammonium perrhenate, [...] Read more.
This paper presents the research results on the synthesis of rhenium catalysts MTO, Re2O7/Al2O3, and M-Re2O7/Al2O3 (where M = Ni, Ag, Co, Cu) from rhenium compounds (ammonium perrhenate, perrhenic acid, nickel(II) perrhenate, cobalt(II) perrhenate, zinc perrhenate, silver perrhenate, and copper(II) perrhenate) derived from waste materials. Methyltrioxorhenium (MTO) was obtained from silver perrhenate with a yield of over 80%, whereas when using nickel(II), cobalt(II), and zinc perrhenates, the product was contaminated with tin compounds and the yield did not exceed 17%. The Re2O7/Al2O3 and M-Re2O7/Al2O3 catalysts were obtained from the above-mentioned rhenium compounds. Alumina obtained in a calcination process of aluminum nitrate nonahydrate was used as a support. The catalysts were characterized in terms of their chemical and phase composition and physicochemical properties. Catalytic activity in model reactions, such as cyclohexene epoxidation and hex-1-ene homometathesis, was also studied. MTO obtained from silver perrhenate showed >70% activity in the epoxidation reaction, thus surpassing commercial MTO (1.0 mol% MTO, room temperature, and reaction time—2 h). Ag-Re2O7/Al2O3, Cu-Re2O7/Al2O3, and H-Re2O7/Al2O3 catalysts were inactive, while Co-Re2O7/Al2O3 and Ni-Re2O7/Al2O3 showed low activity (<43%) in the hex-1-ene homometathesis reaction. Only Re2O7/Al2O3 catalysts achieved >70% activity in this reaction (2.5 wt% Re, room temperature, and reaction time—2 h). The results indicate the potential of using rhenium compounds derived from waste materials to synthesize active catalysts for chemical processes. Full article
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16 pages, 3399 KB  
Article
Relationship Between Filler Type, Thermomechanical Properties, and Aging of RTV Silicone Foams
by Xavier M. Torres, John R. Stockdale, Adam Pacheco, Shelbie A. Legett, Lindsey B. Bezek, Bart Benedikt, Andrea Labouriau and Santosh Adhikari
Polymers 2025, 17(14), 1998; https://doi.org/10.3390/polym17141998 - 21 Jul 2025
Viewed by 578
Abstract
Room-temperature vulcanizing (RTV) silicone foams are used in many industrial applications that require the material to perform over long time periods. However, mechanical properties tend to deteriorate when these foams age under a compressive load. The chemical aging is attributed to the presence [...] Read more.
Room-temperature vulcanizing (RTV) silicone foams are used in many industrial applications that require the material to perform over long time periods. However, mechanical properties tend to deteriorate when these foams age under a compressive load. The chemical aging is attributed to the presence of unreacted functional groups of the prepolymers, residues from acid, and catalytically active tin (II) species. Here, an optimized thermal treatment of an RTV foam that achieves completion of curing reactions and deactivation of reactive species is proposed. Foams that were thermally aged for three months under compressive load showed no signs of compression set, indicative of the effectiveness of the implemented post-curing approach. In addition, the effects of fillers (diatomaceous earth, fumed silica, and carbon nanofibers) on thermomechanical properties were investigated. Tensile strength, tear strength, and thermal conductivity increased when these fillers were added to the unfilled RTV formulation, with carbon nanofibers (CNFs) being the most effective filler. Rheological studies of RTV formulations indicated that 2.5 wt.% of CNFs is the upper limit that can be added to the RTV formulation. Full article
(This article belongs to the Special Issue Functional Polymer Composites: Synthesis and Application)
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20 pages, 3533 KB  
Article
Creation of Crystalline Orientation of Tin(II) Oxide Polycrystals with High Photocatalytic Activity
by Svetlana A. Kuznetsova, Olga S. Khalipova and Yu-Wen Chen
Molecules 2025, 30(13), 2870; https://doi.org/10.3390/molecules30132870 - 6 Jul 2025
Cited by 1 | Viewed by 582
Abstract
Tin(II) oxide is a promising material for photocatalytic wastewater treatment. However, the established relationships between particle size, shape, and photocatalytic activity of SnO are contradictory, indicating the influence of other factors. In this work, the effect of the SnO crystallographic texture on its [...] Read more.
Tin(II) oxide is a promising material for photocatalytic wastewater treatment. However, the established relationships between particle size, shape, and photocatalytic activity of SnO are contradictory, indicating the influence of other factors. In this work, the effect of the SnO crystallographic texture on its band gap and photocatalytic activity was shown for the first time. The relationship between the methods (microwave and hydrothermal microwave) and synthesis conditions (time, pressure, and chemical composition of the suspension) of polycrystalline tin oxide(II) and the crystallographic texture was studied. The crystallographic texture was estimated by the Harris method using the repeatability factor and the Lotgering coefficient. The formation of crystallites oriented in the growth plane (00l) was facilitated by the carbonate medium of the suspension. In the ammonia medium, crystallites were preferably formed in the plane (h0l). Increasing the time and pressure leads to the recrystallization of SnO. The band gap energy of the SnO increases from 3.0 to 3.6 eV, and the rate of photodestruction of methyl orange decreases with the growth of crystallites in the (00l) plane from 17 to 40%. Full article
(This article belongs to the Special Issue Inorganic Chemistry in Asia)
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15 pages, 4917 KB  
Article
Synergistic Integration of g-C3N4 with SnS: Unlocking Enhanced Photocatalytic Efficiency and Electrochemical Stability for Dual-Functional Applications
by Aya Ahmed, Farid M. Abdel-Rahim, Fatemah H. Alkallas, Amira Ben Gouider Trabelsi, Shoroog Alraddadi and Abdelaziz M. Aboraia
Catalysts 2025, 15(7), 629; https://doi.org/10.3390/catal15070629 - 27 Jun 2025
Viewed by 692
Abstract
The synthesis of graphitic carbon nitride (g-C3N4) coupled with tin sulfide (SnS) has been identified as an effective method for improving the photocatalytic and electrochemical performance of SnS, a promising material for environmental and energy-related applications. In this study, [...] Read more.
The synthesis of graphitic carbon nitride (g-C3N4) coupled with tin sulfide (SnS) has been identified as an effective method for improving the photocatalytic and electrochemical performance of SnS, a promising material for environmental and energy-related applications. In this study, we focused on how g-C3N4 influences the structural, optical, electrochemical, and functional properties of SnS. XRD and FTIR confirmed the formation of SnS/g-C3N4 heterostructure, while surface morphology analysis by SEM showed proper dispersion of SnS particles over g-C3N4 with a good interface contact. The SnS/g-C3N4 composite itself demonstrated improved photocatalytic performance, with the degradation rate of methylene blue reaching approximately 94% under visible light irradiation compared to the moderate activity of SnS. This enhancement can be credited to the successful charge carrier separation enabled by the type II heterojunction created between SnS and g-C3N4. Moreover, the composite presented improved electrochemical activity with a specific capacitance of 1340 F·g−1 at a scan rate of 10 A·g−1 and good cycling stability, where the capacitance was 92% after 5000 cycles. As such, these SnS/g-C3N4 composites suggest the specific application of this class of material in photocatalytic degradation as well as energy storage, putting forward new effective resolutions to environmental and energy issues. Full article
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26 pages, 5112 KB  
Article
Mixed Halide Isothiocyanate Tin(II) Compounds, SnHal(NCS): Signs of Tetrel Bonds as Bifurcated Extensions of Long-Range Asymmetric 3c-4e Bonds
by Hans Reuter
Molecules 2025, 30(13), 2700; https://doi.org/10.3390/molecules30132700 - 23 Jun 2025
Viewed by 587
Abstract
As part of a systematic study on the structures of the mixed halide isothiocyanates, SnIIHal(NCS), their single crystals were grown and structurally characterized. For Hal = F (1), the SnClF structure type was confirmed, while with Hal = Cl [...] Read more.
As part of a systematic study on the structures of the mixed halide isothiocyanates, SnIIHal(NCS), their single crystals were grown and structurally characterized. For Hal = F (1), the SnClF structure type was confirmed, while with Hal = Cl (2), Br (3), and I (4), there are three isostructural compounds of a new structure type, and for Hal = Cl (5), there is a second modification of a third structure type. These structure types have been described with respect to the composition and coordination geometry of the first, second, and van der Waals crust coordination spheres and their dependence on the halogen size and thiocyanate binding modes. With respect to the first coordination spheres, all three structure types constitute one-dimensional coordination polymers. In 1, “ladder”-type double chains result from μ3-bridging fluorine atoms, and in 24, single-chains built up from μ2-halogen atoms are pairwise “zipper”-like interconnected via κ2NS-bridging NCS ligands, which manage the halogen-linked chain assembly in the double chains of 5. Based on the octet rule, short atom distances are interpreted in terms of 2c-2e and various (symmetrical, quasi-symmetrical, and asymmetrical) kinds of 3c-4e bonds. Weak contacts, the topology of which suggests the extension of the latter bonding concept, are identified as electron-deficient, bifurcated tetrel bonds. Full article
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18 pages, 2436 KB  
Article
Photoelectrochemical and Photocatalytic Properties of SnS/TiO2 Heterostructure Thin Films Prepared by Magnetron Sputtering Method
by Yaoxin Ding, Jiahao Leng, Mingyang Zhang and Jie Shen
Inorganics 2025, 13(7), 208; https://doi.org/10.3390/inorganics13070208 - 20 Jun 2025
Cited by 1 | Viewed by 690
Abstract
Tin(II) sulfide(SnS)/titanium(IV) oxide (TiO2) heterostructure thin films were prepared by radio-frequency magnetron sputtering to investigate the enhancement effect of the formed heterojunction on the photocatalytic performance. By adjusting the sputtering time to vary the thickness of the SnS layer, the crystallinity [...] Read more.
Tin(II) sulfide(SnS)/titanium(IV) oxide (TiO2) heterostructure thin films were prepared by radio-frequency magnetron sputtering to investigate the enhancement effect of the formed heterojunction on the photocatalytic performance. By adjusting the sputtering time to vary the thickness of the SnS layer, the crystallinity and light-absorption properties of the light-absorbing layer and the quality of the heterojunction interface were effectively controlled, thereby optimizing the fabrication process of the heterojunction. It was found that when the SnS layer thickness was 244 nm and the TiO2 layer thickness was 225 nm, the heterostructure film exhibited optimal photoelectrochemical performance, generating the highest photocurrent of 3.03 µA/cm2 under visible light, which was 13.8 times that of a pure TiO2 film and 2.4 times that of a pure SnS film of the same thickness. Additionally, it demonstrated the highest degradation efficiency for methylene blue dye. The improved photoelectrochemical performance of the SnS/TiO2 heterostructure film can be primarily attributed to the following: (1) the incorporation of narrow-bandgap SnS effectively broadens the light-absorption range, improving visible-light harvesting; (2) the staggered band alignment between SnS and TiO2 forms a type-II heterojunction, significantly enhancing the charge carrier separation and transport efficiency. The present work demonstrated the feasibility of magnetron sputtering for constructing high-quality SnS/TiO2 heterostructures, providing insights into the design and fabrication of photocatalytic heterojunctions. Full article
(This article belongs to the Special Issue Advanced Inorganic Semiconductor Materials, 3rd Edition)
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13 pages, 1947 KB  
Article
Photothermal Performance of 2D Material-Based Nanoparticles for Biomedical Applications
by Amir Eghbali, Nikolay V. Pak, Aleksey V. Arsenin, Valentyn Volkov and Andrey A. Vyshnevyy
Nanomaterials 2025, 15(12), 942; https://doi.org/10.3390/nano15120942 - 18 Jun 2025
Viewed by 918
Abstract
Photothermal therapy (PTT) is one of the rapidly developing methods for cancer treatment based on the strong light-to-heat conversion by nanoparticles. Over the past decade, the palette of photonic materials has expanded drastically, and nanoparticle fabrication techniques can now preserve the optical response [...] Read more.
Photothermal therapy (PTT) is one of the rapidly developing methods for cancer treatment based on the strong light-to-heat conversion by nanoparticles. Over the past decade, the palette of photonic materials has expanded drastically, and nanoparticle fabrication techniques can now preserve the optical response of a bulk material in produced nanoparticles. This progress potentially holds opportunities for the efficiency enhancement of PTT, which have not fully explored yet. Here we study the photothermal performance of spherical nanoparticles (SNs) composed of novel two-dimensional (2D) and conventional materials with existing or potential applications in photothermal therapy such as MoS2, PdSe2, Ti3C2, TaS2, and TiN. Using the Mie theory, we theoretically analyze the optical response of SNs across various radii of 5–100 nm in the near-infrared (NIR) region with a particular focus on the therapeutic NIR-II range (1000–1700 nm) and radii below 50 nm. Our calculations reveal distinct photothermal behaviors: Large (radius > 50 nm) nanoparticles made of van der Waals semiconductors and PdSe2 perform exceptionally well in the NIR-I range (750–950 nm) due to excitonic optical responses, while Ti3C2 nanoparticles achieve broad effectiveness across both NIR zones due to their dual dielectric/plasmonic properties. Small TiN SNs excel in the NIR-I zone due to the plasmonic response of TiN at shorter wavelengths. Notably, the van der Waals metal TaS2 emerges as the most promising photothermal transduction agent in the NIR-II region, particularly for smaller nanoparticles, due to its plasmonic resonance. Our insights lay a foundation for designing efficient photothermal transduction agents, with significant implications for cancer therapy and other biomedical applications. Full article
(This article belongs to the Special Issue Nanostructured Materials and Coatings for Biomedical Applications)
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15 pages, 2677 KB  
Article
Enzyme-Based Solid-Phase Electrochemiluminescence Sensors with Stable, Anchored Emitters for Sensitive Glucose Detection
by Chunyin Wei, Yanyan Zheng, Fei Yan and Lifang Xu
Biosensors 2025, 15(5), 332; https://doi.org/10.3390/bios15050332 - 21 May 2025
Cited by 5 | Viewed by 886
Abstract
Glucose (Glu) detection, as a fundamental analytical technique, has applications in medical diagnostics, clinical testing, bioanalysis and environmental monitoring. In this work, a solid-phase electrochemiluminescence (ECL) enzyme sensor was developed by immobilizing the ECL emitter in a stable manner within bipolar silica nanochannel [...] Read more.
Glucose (Glu) detection, as a fundamental analytical technique, has applications in medical diagnostics, clinical testing, bioanalysis and environmental monitoring. In this work, a solid-phase electrochemiluminescence (ECL) enzyme sensor was developed by immobilizing the ECL emitter in a stable manner within bipolar silica nanochannel array film (bp-SNA), enabling sensitive glucose detection. The sensor was constructed using an electrochemical-assisted self-assembly (EASA) method with various siloxane precursors to quickly modify the surface of indium tin oxide (ITO) electrodes with a bilayer SNA of different charge properties. The inner layer, including negatively charged SNA (n-SNA), attracted the positively charged ECL emitter tris(2,2′-bipyridyl)ruthenium(II) (Ru(bpy)32+) via electrostatic interaction, while the outer layer, including positively charged SNA (p-SNA), repelled it, forming a barrier that efficiently concentrated the Ru(bpy)32+ emitter in a stable manner. After modifying the amine groups on the p-SNA surface with aldehyde groups, glucose oxidase (GOx) was covalently immobilized, forming the enzyme electrode. In the presence of glucose, GOx catalyzed the conversion of glucose to hydrogen peroxide (H2O2), which acted as a quencher for the Ru(bpy)32+/triethanolamine (TPA) system, reducing the ECL signal and enabling quantitative glucose analysis. The sensor exhibited a wide linear range from 10 μM to 7.0 mM and a limit of detection (LOD) of 1 μM (S/N = 3). Glucose detection in fetal bovine serum was realized. By replacing the enzyme type on the electrode surface, this sensing strategy holds the potential to provide a universal platform for the detection of different metabolites. Full article
(This article belongs to the Special Issue Recent Developments in Nanomaterial-Based Electrochemical Biosensors)
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22 pages, 4895 KB  
Article
Ore Genesis of the Huanggang Iron-Tin-Polymetallic Deposit, Inner Mongolia: Constraints from Fluid Inclusions, H–O–C Isotopes, and U-Pb Dating of Garnet and Zircon
by Hanwen Xue, Keyong Wang, Qingfei Sun, Junchi Chen, Xue Wang and Haoming Li
Minerals 2025, 15(5), 518; https://doi.org/10.3390/min15050518 - 14 May 2025
Viewed by 700
Abstract
The Huanggang iron-tin deposit, located in the southern Greater Khingan Range, is one of the largest Fe-Sn deposits in Northern China (NE China). Iron-tin mineralization occurs mainly in the contact zone between granitoid intrusions and the marble of the Huanggang and Dashizhai formations. [...] Read more.
The Huanggang iron-tin deposit, located in the southern Greater Khingan Range, is one of the largest Fe-Sn deposits in Northern China (NE China). Iron-tin mineralization occurs mainly in the contact zone between granitoid intrusions and the marble of the Huanggang and Dashizhai formations. Six mineralization stages are identified: (I) anhydrous skarn, (II) hydrous skarn, (III) cassiterite-quartz-calcite, (IV) pyrite-arsenopyrite-quartz-fluorite, (V) polymetallic sulfides-quartz, and (VI) carbonate ones. Fluid inclusions (FIs) analysis reveals that Stage I garnet and Stage II–III quartz host liquid-rich (VL-type), vapor-rich two-phase (LV-type), and halite-bearing three-phase (SL-type) inclusions. Stage IV quartz and fluorite, along with Stage V quartz, are dominated by VL- and LV-type inclusions, while Stage VI calcite contains exclusively VL-type inclusions. The FIs in Stages I to VI homogenized at 392–513, 317–429, 272–418, 224–347, 201–281, and 163–213 °C, with corresponding salinities of 3.05–56.44, 2.56–47.77, 2.89–45.85, 1.39–12.42, 0.87–10.62, and 4.48–8.54 wt% NaCl equiv., respectively. The H–O–C isotopes data imply that fluids of the anhydrous skarn stage (δD = −101.2 to −91.4‰, δ18OH2O = 5.0 to 6.0‰) were of magmatic origin, the fluids of hydrous skarn and oxide stages (δD = −106.3 to −104.7‰, δ18OH2O = 4.3 to 4.9‰) were characterized by fluid mixing with minor meteoric water, while the fluids of sulfide stages (δD = −117.4 to −108.6‰, δ18OH2O = −3.4 to 0.3‰, δ13CV-PDB= −12.2 to −10.9‰, and δ18OV-SMOW = −2.2 to −0.7‰) were characterized by mixing of significant amount of meteoric water. The ore-forming fluids evolved from a high-temperature, high-salinity NaCl−H2O boiling system to a low-temperature, low-salinity NaCl−H2O mixing system. The garnet U-Pb dating constrains the formation of skarn to 132.1 ± 4.7 Ma (MSWD = 0.64), which aligns, within analytical uncertainty, with the weighted-mean U−Pb age of zircon grains in ore-related K-feldspar granite (132.6 ± 0.9 Ma; MSWD = 1.5). On the basis of these findings, the Huanggang deposit, formed in the Early Cretaceous, is a typical skarn-type system, in which ore precipitation was principally controlled by fluid boiling and mixing. Full article
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25 pages, 4627 KB  
Article
Laser-Based Characterization and Classification of Functional Alloy Materials (AlCuPbSiSnZn) Using Calibration-Free Laser-Induced Breakdown Spectroscopy and a Laser Ablation Time-of-Flight Mass Spectrometer for Electrotechnical Applications
by Amir Fayyaz, Muhammad Waqas, Kiran Fatima, Kashif Naseem, Haroon Asghar, Rizwan Ahmed, Zeshan Adeel Umar and Muhammad Aslam Baig
Materials 2025, 18(9), 2092; https://doi.org/10.3390/ma18092092 - 2 May 2025
Cited by 1 | Viewed by 1026
Abstract
In this paper, we present the analysis of functional alloy samples containing metals aluminum (Al), copper (Cu), lead (Pb), silicon (Si), tin (Sn), and zinc (Zn) using a Q-switched Nd laser operating at a wavelength of 532 nm with a pulse duration of [...] Read more.
In this paper, we present the analysis of functional alloy samples containing metals aluminum (Al), copper (Cu), lead (Pb), silicon (Si), tin (Sn), and zinc (Zn) using a Q-switched Nd laser operating at a wavelength of 532 nm with a pulse duration of 5 ns. Nine pelletized alloy samples were prepared, each containing varying chemical concentrations (wt.%) of Al, Cu, Pb, Si, Sn, and Zn—elements commonly used in electrotechnical and thermal functional materials. The laser beam is focused on the target surface, and the resulting emission spectrum is captured within the temperature interval of 9.0×103 to 1.1×104 K using a set of compact Avantes spectrometers. Each spectrometer is equipped with a linear charged-coupled device (CCD) array set at a 2 μs gate delay for spectrum recording. The quantitative analysis was performed using calibration-free laser-induced breakdown spectroscopy (CF-LIBS) under the assumptions of optically thin plasma and self-absorption-free conditions, as well as local thermodynamic equilibrium (LTE). The net normalized integrated intensities of the selected emission lines were utilized for the analysis. The intensities were normalized by dividing the net integrated intensity of each line by that of the aluminum emission line (Al II) at 281.62 nm. The results obtained using CF-LIBS were compared with those from the laser ablation time-of-flight mass spectrometer (LA-TOF-MS), showing good agreement between the two techniques. Furthermore, a random forest technique (RFT) was employed using LIBS spectral data for sample classification. The RFT technique achieves the highest accuracy of ~98.89% using out-of-bag (OOB) estimation for grouping, while a 10-fold cross-validation technique, implemented for comparison, yields a mean accuracy of ~99.12%. The integrated use of LIBS, LA-TOF-MS, and machine learning (e.g., RFT) enables fast, preparation-free analysis and classification of functional metallic materials, highlighting the synergy between quantitative techniques and data-driven methods. Full article
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19 pages, 2066 KB  
Article
Diorganotin(IV) Complexes of Organoselenolato Ligands with Pyrazole Moieties—Synthesis, Structure and Properties
by Melinda Tamas, Roxana A. Butuza, Monica Dan and Anca Silvestru
Molecules 2025, 30(7), 1648; https://doi.org/10.3390/molecules30071648 - 7 Apr 2025
Viewed by 860
Abstract
Diorganotin(IV) compounds of types RR′Sn(SeCH2CH2pz)2 [R = R′ = nBu (2), Ph (3); R = 2-(Me2NCH2)C6H4, R′ = Me (4), nBu ( [...] Read more.
Diorganotin(IV) compounds of types RR′Sn(SeCH2CH2pz)2 [R = R′ = nBu (2), Ph (3); R = 2-(Me2NCH2)C6H4, R′ = Me (4), nBu (5), Ph (6)], and RR′SnX(SeCH2CH2pz) [R = 2-(Me2NCH2)C6H4, R′ = nBu, X = Cl (7), R′ = Me, X = SCN (9)], as well as [2-(Me2NCH2)C6H4](Me)Sn(NCS)2 (8), and the tin(II) Sn(SeCH2CH2pz)2 (10) (pz = pyrazole), were prepared by salt metathesis reactions between the appropriate diorganotin(IV) dichloride or dipseudohalide and Na[SeCH2CH2pz], with the latter freshly prepared from (pzCH2CH2)2Se2 (1). The solution behaviour of these compounds was investigated by multinuclear NMR (1H, 13C, 77Se, 119Sn), and the NMR spectra showed the existence of the Se–Sn bonds in solution. Compounds 4 and 5 showed decomposition in a solution of chlorinated solvents with the formation of selenium bridged dimeric species of type {[2-(Me2NCH2)C6H4](R’)Se}2 [R′ = Me (4-a), nBu (5-a)], as the single-crystal X-ray diffraction studies revealed, in contrast with compound 9, for which a monomeric structure was observed with the desired composition. The solid state structures of 4-a, 5-a, 8, and 9 revealed N→Sn intramolecular coordination of the nitrogen atom in the pendant CH2NMe2 arm. The NMR spectra suggested such a coordination at room temperature only for compound 7. Full article
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Article
In Situ Geochemical and Sulfur Isotopic Composition of Pyrites from the Jiepailing Tin–Beryllium Polymetallic Deposit, Southern Hunan Province, China: Implications for Ore-Forming Processes
by Gao-Feng Du, Xiang-Ying Ling, Dan Wang, Wei-Jian Zhou, Liu Yang, You-Yue Lu and Zun-Zun Zhang
Minerals 2025, 15(3), 312; https://doi.org/10.3390/min15030312 - 18 Mar 2025
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Abstract
The Jiepailing deposit in southern Hunan is a typical large to super-large polymetallic tin deposit enriched in beryllium and other rare metals. To enhance the understanding of the mineralization processes of the Jiepailing deposit, detailed mineralogical, in situ geochemical, and sulfur isotopic analyses [...] Read more.
The Jiepailing deposit in southern Hunan is a typical large to super-large polymetallic tin deposit enriched in beryllium and other rare metals. To enhance the understanding of the mineralization processes of the Jiepailing deposit, detailed mineralogical, in situ geochemical, and sulfur isotopic analyses were conducted on pyrite closely associated with tin–polymetallic mineralization. Five types of pyrite have been identified in the deposit: (1) euhedral to subhedral medium- to coarse-grained pyrite (PyI) in tungsten–tin ore; anhedral fine-grained pyrite (PyII) in tin polymetallic–fluorite ore; anhedral fine-grained or aggregate pyrite (PyIII) in lead–zinc ore; euhedral to subhedral coarse-grained pyrite (PyIV) in beryllium–fluorite mineralization; and subhedral to anhedral fine-grained pyrite (PyV) in carbonate veinlets developed in the wall rock. Backscattered electron imaging indicates consistent structural features across the five types of pyrite. In situ trace element analysis reveals differences in trace element concentrations among the pyrite types. PyI is relatively enriched in Sn, Cu, and Co. In contrast, PyIII is enriched in Pb, Zn, Sn, and Ti, while PyIV and PyV are enriched in Ag and Sb. PyI has a Co/Ni ratio more than 1, while the Co/Ni ratios in the other four types of pyrite are less than 1. LA-MC-ICP-MS in situ sulfur isotope analysis shows δ34S values ranging from 2.5‰ to 5.8‰ (average 4.3‰, PyI), 2.5‰ to 5.8‰ (average 4.3‰, PyII), −7.6‰ to 9.5‰ (average 3.9‰, PyIII), −3.7‰ to 10.6‰ (average 3.6‰, PyIV), and 6.8‰ to 14.1‰ (average 9.2‰, PyV). Based on previous studies, regional geological background, deposit characteristics, and the in situ trace element and sulfur isotope compositions of pyrite, it is inferred that the various ore bodies in the Jiepailing deposit are products of Late Cretaceous magmatic–hydrothermal activity. The early ore-forming fluid originated from magmatic sources and during the migration into the wall rock and shallow formations, mixed with fluids primarily derived from atmospheric precipitation. Temperature, pressure, and composition changed of the ore-forming fluid which carried a large amount of substances, leading to tungsten–tin, tin polymetallic–fluorite, lead–zinc, and beryllium–fluorite mineralization, followed by carbonation during the late-stage mineralization. Full article
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