Inorganics

17 pages, 3736 KiB

Open AccessArticle

Stem Bark-Mediated Green Synthesis of Silver Nanoparticles from Pyrus pashia: Characterization, Antioxidant, and Antibacterial Properties

by Lekha Nath Khanal, Purna Prasad Dhakal, Mani Ram Kandel, Debendra Acharya, Ek Raj Baral, Kisan Chhetri and Surya Kant Kalauni

Inorganics 2023, 11(6), 263; https://doi.org/10.3390/inorganics11060263 - 20 Jun 2023

Cited by 2 | Viewed by 1712

Abstract

The investigation of using medicinal plants for the production and application of silver nanoparticles (AgNPs) has attracted growing research interest. In this study, AgNPs are synthesized from the stem barks of the Pyrus pashia medicinal plant using a biosynthetic strategy. The reaction conditions [...] Read more.

The investigation of using medicinal plants for the production and application of silver nanoparticles (AgNPs) has attracted growing research interest. In this study, AgNPs are synthesized from the stem barks of the Pyrus pashia medicinal plant using a biosynthetic strategy. The reaction conditions were optimized under ambient conditions, including concentration, temperature, time, and pH, and various techniques were employed, such as UV-visible, FTIR, XRD, FESEM, and TEM, to characterize the synthesized AgNPs. The AgNPs produced through this biosynthesis method were found to be spherical and polydispersed, with an average size of 23.92 ± 7.04 nm. The synthesized AgNPs demonstrated an enhanced DPPH free radical scavenging capacity compared to the aqueous extract, with IC₅₀ values of 10.67 ± 0.05 µg/mL and 13.66 ± 0.35 µg/mL, respectively. In the agar well diffusion method, the synthesized AgNPs showed higher antibacterial activity than that of the extract against Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 25923), Enterococcus faecalis (ATCC 29212), Salmonella typhi (ATCC 14028), and Shigella sonnei (ATCC 25931). Based on these findings, the study suggests that green synthesized AgNPs from P. pashia could be used for biomedical applications. Full article

(This article belongs to the Special Issue Functional Inorganic Materials for Biomedical Application)

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20 pages, 2848 KiB

Open AccessReview

Carbon Quantum Dots: The Role of Surface Functional Groups and Proposed Mechanisms for Metal Ion Sensing

by Hasan Shabbir, Edit Csapó and Marek Wojnicki

Inorganics 2023, 11(6), 262; https://doi.org/10.3390/inorganics11060262 - 20 Jun 2023

Cited by 21 | Viewed by 3754

Abstract

Carbon dots (CDs) are zero-dimensional nanomaterials composed of carbon and surface groups attached to their surface. CDs have a size smaller than 10 nm and have potential applications in different fields such as metal ion detection, photodegradation of pollutants, and bio-imaging, in this [...] Read more.

Carbon dots (CDs) are zero-dimensional nanomaterials composed of carbon and surface groups attached to their surface. CDs have a size smaller than 10 nm and have potential applications in different fields such as metal ion detection, photodegradation of pollutants, and bio-imaging, in this review, the capabilities of CDs in metal ion detection will be described. Quantum confinement is generally viewed as the key factor contributing to the uniqueness of CDs characteristics due to their small size and the lack of attention on the surface functional groups and their roles is given, however, in this review paper, the focus will be on the functional group and the composition of CDs. The surface functional groups depend on two parameters: (i) the oxidation of precursors and (ii) their composition. The mechanism of metal ion detection is still being studied and is not fully understood. This review article emphasizes the current development and progress of CDs, focusing on metal ion detection based on a new perspective. Full article

(This article belongs to the Special Issue 10th Anniversary of Inorganics: Organometallic Chemistry)

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19 pages, 4140 KiB

Open AccessArticle

A Boron-Containing Analogue of Acetaminophen Induces Analgesic Effect in Hot Plate Test and Limited Hepatotoxicity

by Melvin Nadir Rosalez, Eunice D. Farfán-García, Jesús Badillo-Romero, Ricardo Iván Córdova-Chávez, José G. Trujillo-Ferrara, José A. Morales-González, Marvin A. Soriano-Ursúa and Marlet Martínez-Archundia

Inorganics 2023, 11(6), 261; https://doi.org/10.3390/inorganics11060261 - 20 Jun 2023

Viewed by 1609

Abstract

Acetaminophen is the most sold drug to treat pain. The TRPV1 channel is among its main targets. Due to its over-the-counter availability, its use is known as the main cause of acute liver failure induced by drugs. In addition, boron-containing compounds (BCC) have [...] Read more.

Acetaminophen is the most sold drug to treat pain. The TRPV1 channel is among its main targets. Due to its over-the-counter availability, its use is known as the main cause of acute liver failure induced by drugs. In addition, boron-containing compounds (BCC) have shown higher efficiency, potency, and affinity than their carbon counterparts. The present study explored the potential analgesic effect and hepatotoxicity of a BCC with a similar chemical structure to acetaminophen. Docking studies were carried out on the TRPV1 channel. In addition, a hot plate test was carried out with three doses of acetaminophen (APAP) and equimolar doses of 4-acetamidophenylboronic acid (4APB) in C57bl/6 mice. These same mice were submitted to a partial hepatectomy and continued compound administration, then they were sacrificed at day seven of treatment to analyze the liver histology and blood chemistry markers. From the in silico assays, it was observed that APAP and 4APB shared interactions with key residues, but 4APB showed a higher affinity on the orthosteric site. Mice administered with 4APB showed a higher latency time than those administered with their equimolar dose of APAP and the control group, with no motor pathway affected. The 4APB groups did not show an increase in hepatic enzyme activity while the APAP did show an increase in activity that was dose-dependent. Although all the experimental groups did show necrosis and inflammation, all APAP groups showed a greater cellular damage than their 4APB counterparts. In addition, the LD₅₀ of 4APB is 409 mg/kg (against APAP-LD₅₀ of 338 mg/kg). Thus, in the current evaluation, 4APB was a better analgesic and safer than APAP. Full article

(This article belongs to the Special Issue Boron Chemistry: Fundamentals and Applications)

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13 pages, 3051 KiB

Open AccessArticle

The Fast Formation of a Highly Active Homogeneous Catalytic System upon the Soft Leaching of Pd Species from a Heterogeneous Pd/C Precursor

by Alexey S. Galushko, Valentina V. Ilyushenkova, Julia V. Burykina, Ruslan R. Shaydullin, Evgeniy O. Pentsak and Valentine P. Ananikov

Inorganics 2023, 11(6), 260; https://doi.org/10.3390/inorganics11060260 - 19 Jun 2023

Cited by 2 | Viewed by 1189

Abstract

Understanding the interface between soluble metal complexes and supported metal particles is important in order to reveal reaction mechanisms in a new generation of highly active homogeneous transition metal catalysts. In this study, we show that, in the case of palladium forming on [...] Read more.

Understanding the interface between soluble metal complexes and supported metal particles is important in order to reveal reaction mechanisms in a new generation of highly active homogeneous transition metal catalysts. In this study, we show that, in the case of palladium forming on a carbon (Pd/C) catalyst from a soluble Pd(0) complex Pd₂dba₃, the nature of deposited particles on a carbon surface turns out to be much richer than previously assumed, even if a very simple experimental procedure is utilized without the use of additional reagents and procedures. In the process of obtaining a heterogeneous Pd/C catalyst, highly active “hidden” metal centers are formed on the carbon surface, which are leached out by the solvent and demonstrate diverse reactivity in the solution phase. The results indicate that heterogeneous catalysts may naturally contain trace amounts of molecular monometallic centers of a different nature by easily transforming them to the homogeneous catalytic system. In line with a modern concept, a heterogenized homogeneous catalyst precursor was found to leach first, leaving metal nanoparticles mostly intact on the surface. In this study, we point out that the previously neglected soft leaching process contributes to high catalyst activity. The results we obtained demand for leaching to be reconsidered as a flexible tool for catalyst construction and for the rational design of highly active and selective homogeneous catalytic systems, starting from easily available heterogeneous catalyst precursors. Full article

(This article belongs to the Special Issue Revealing Reaction Mechanisms in Homogeneous Transition Metal Catalysis, 2nd Edition)

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19 pages, 3700 KiB

Open AccessArticle

Flexible Co(II)-and Ni(II)-Based Cationic 2D Metal–Organic Frameworks Based on a Charge-Neutral (O,O)-Donor Bridge

by Pavel A. Demakov, Konstantin A. Kovalenko, Alexander N. Lavrov and Vladimir P. Fedin

Inorganics 2023, 11(6), 259; https://doi.org/10.3390/inorganics11060259 - 17 Jun 2023

Viewed by 1070

Abstract

Two new metal–organic frameworks based on highly flexible 1,4-diazabicyclo[2.2.2]octane N,N′-dioxide (odabco) ligands were successfully synthesized and characterized. Their crystallographic formulae are [M(DMF)₂(odabco)₂](ClO₄)₂·dioxane, where M²⁺ = Co²⁺ (1) and Ni²⁺ ( [...] Read more.

Two new metal–organic frameworks based on highly flexible 1,4-diazabicyclo[2.2.2]octane N,N′-dioxide (odabco) ligands were successfully synthesized and characterized. Their crystallographic formulae are [M(DMF)₂(odabco)₂](ClO₄)₂·dioxane, where M²⁺ = Co²⁺ (1) and Ni²⁺ (2), and DMF is N,N-dimethylformamide. The title compounds possess cationic 2D coordination networks filled with perchlorate anions and dioxane solvent molecules in the interlayer space, with 20% solvent accessible volume. Carbon dioxide adsorption measurements for desolvated samples 1a and 2a gave 511 m²/g and 377 m²/g specific surface areas, respectively, revealing the first example of gas adsorption properties in the structure based on a flexible odabco bridge, despite the presence of large counteranions within the positively charged network. Magnetization measurements for 1, 1a, 2 and 2a reveal their paramagnetic nature to be in a reasonable agreement with crystal structures, and almost no solvent dependence of the magnetization characteristics. A decrease in the effective magnetic moment observed at low temperatures is attributed mostly to zero-field level-splitting in the octahedral Ni²⁺ and Co²⁺ ions. Full article

(This article belongs to the Special Issue 10th Anniversary of Inorganics: Coordination Chemistry)

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17 pages, 5726 KiB

Open AccessArticle

Preparation and Study of Photocatalytic Properties of (M(M=Pt, Ag and Au)-TiO₂)@MoS₂ Nanocomposites

by Liying Ju, Dunhua Hong, Xing Jin, Hongxian Liu, Xiude Yang, Liying Nie, Qibin Liu, Zhixi Gao, Wei Zhu, Yi Wang and Xiang Yang

Inorganics 2023, 11(6), 258; https://doi.org/10.3390/inorganics11060258 - 15 Jun 2023

Cited by 1 | Viewed by 1049

Abstract

There have been many articles on the degradation of pollutants by binary and ternary nanocomposites in the field of photocatalysis. However, there has been no research comparing the photocatalytic performance of Rhodamine B (Rh B) between (M(M=Pt, Ag and Au)-TiO₂)@MoS₂ [...] Read more.

There have been many articles on the degradation of pollutants by binary and ternary nanocomposites in the field of photocatalysis. However, there has been no research comparing the photocatalytic performance of Rhodamine B (Rh B) between (M(M=Pt, Ag and Au)-TiO₂)@MoS₂ nanocomposites and binary nanocomposites. To this end, we prepared and studied (M(M=Pt, Ag and Au)-TiO₂)@MoS₂ nanocomposites and compared their photocatalytic degradation efficiency with binary composites and parent materials for Rhodamine B. We concluded that the best ternary polymer nanocomposite for degrading Rhodamine B is (Pt(5 wt%)-TiO₂(15 wt%))@MoS₂. In this work, a series of MoS₂, TiO₂@MoS₂, and (M(M=Pt, Ag and Au)-TiO₂)@MoS₂ nanocomposites with various compositions were synthesized by the hydrothermal and deposition–precipitation methods, and their photocatalytic characteristics were studied in depth using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) photoluminescence spectra (PL), FTIR spectra, UV–Vis DRS spectra, and BET analyzer. The results confirmed that TiO₂ and M(Pt, Ag and Au) nanoparticles (NPs) were evenly distributed on MoS₂ nanosheets (NSs) to form (M(M=Pt, Ag and Au)-TiO₂)@MoS₂ nanocomposite heterojunction. The UV–Vis absorption spectrum test results indicated that (Pt(5 wt%)-TiO₂(15 wt%))@MoS₂ ternary heterojunction nanocomposites exhibited the highest photocatalysis activity, with the maximum value of 99.0% compared to 93% for TiO₂(15 wt%)@MoS₂, 96.5% for (Ag(5 wt%)-TiO₂(15 wt%))@MoS₂, and 97.8% for (Au(5 wt%)-TiO₂(15 wt%))@MoS₂ within 9 min. The advanced structure of (Pt-TiO₂)@MoS₂ improved both light harvesting and electron transfer in the photocatalytic composites, contributing to remarkable catalytic effectiveness and extended durability for the photodegradation of Rhodamine B (Rh B). In-depth discussions of the potential growth and photocatalytic mechanism, which will help improve the energy and environmental fields, are included. Full article

(This article belongs to the Special Issue Optoelectronic Properties of Metal Oxide Semiconductors)

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9 pages, 2907 KiB

Open AccessArticle

Revealing the Electrochemistry of All-Solid-State Li-SeS₂ Battery via Transmission Electron Microscopy

by Rui Yan, Fangchao Liu and Zhengwen Fu

Inorganics 2023, 11(6), 257; https://doi.org/10.3390/inorganics11060257 - 13 Jun 2023

Viewed by 1109

Abstract

Li-SeS₂ batteries balance the opposing and complimentary qualities of Li-S and Li-Se batteries by having a high specific capacity and high electrical conductivity. However, there is still a lack of knowledge regarding the electrochemical characteristics of Li-SeS₂ all-solid-state batteries (ASSB). Herein, [...] Read more.

Li-SeS₂ batteries balance the opposing and complimentary qualities of Li-S and Li-Se batteries by having a high specific capacity and high electrical conductivity. However, there is still a lack of knowledge regarding the electrochemical characteristics of Li-SeS₂ all-solid-state batteries (ASSB). Herein, transmission electron microscopy (TEM) is used to reveal the electrochemistry of a Li-SeS₂ battery. It is discovered that, without the Polyethylene glycol (PEG), amorphous SeS₂ in Li-SeS₂ ASSB change into crystalline selenium and a small amount of sulfur. The continuous loss of sulfur from the active material may be related to the failure of the cell at 15 cycles and the severe instability of the Coulombic efficiency. It was found that the PEG coating selenium disulfide graphene composite (PEG@rGO-SeS₂) cathode maintained a specific capacity of 258 mAh g⁻¹ and a stable Coulombic efficiency of about 97% after 50 cycles. TEM analysis shows that the charging product remains as a granular amorphous selenium disulfide with a constant Se/S ratio during cycling. The PEG-protected selenium disulfide can effectively limit the loss of elemental sulfur and regulate the reaction mechanism of the Li-SeS₂ batteries. Full article

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11 pages, 3173 KiB

Open AccessReview

Import and Implications of Vanadium in Live Aspects

by Dieter Rehder

Inorganics 2023, 11(6), 256; https://doi.org/10.3390/inorganics11060256 - 12 Jun 2023

Cited by 3 | Viewed by 1121

Abstract

In Earth’s regions accessible for living organisms (Earth’s crust, crude oil, water sanctuaries and lower atmosphere), vanadium is present in the oxidation states +III and—essentially—+IV (cationic) and +V (cationic and anionic), with the redox interchange and biochemical recycling often monitored by bacteria. Organisms [...] Read more.

In Earth’s regions accessible for living organisms (Earth’s crust, crude oil, water sanctuaries and lower atmosphere), vanadium is present in the oxidation states +III and—essentially—+IV (cationic) and +V (cationic and anionic), with the redox interchange and biochemical recycling often monitored by bacteria. Organisms having available vanadium-containing (bio)molecules with essential functions for life include marine brown algae (haloperoxidases), ascidians and fan worms, as well as terrestrial organisms, viz., nitrogen-fixing bacteria (associated with the roots of legumes), and the fly agaric mushroom. The hypohalite generated by the algal haloperoxidases in turn is involved in the emission of bromoform into the atmosphere. Nitrogen fixation (N₂ ε NH₄⁺) is a process of immanent importance for life on our planet. Other bacterial issues include the reduction of vanadate to VO²⁺. Medicinal applications of vanadium coordination compounds are directed towards the treatment of diabetes mellitus (vanadium complexes with hypoglycemic activity) and cancer—although boundaries are set due to side effects such as oxidative damage elicited by vanadium-induced hyperoxide formation. Physiological actions of vanadium are often invoked due to the structural and physiological similarity between vanadate and phosphate. An additional field of medicinal applications addresses the treatment of cancer, such as leukaemia, malignant melanoma and bone cancer. Full article

(This article belongs to the Special Issue Vanadium in the Center: Current Chemistry and Utilization of the Versatile Metal)

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16 pages, 4906 KiB

Open AccessArticle

Molecular Switching through Chalcogen-Bond-Induced Isomerization of Binuclear (Diaminocarbene)Pd^II Complexes

by Roman A. Popov, Alexander S. Novikov, Vitalii V. Suslonov and Vadim P. Boyarskiy

Inorganics 2023, 11(6), 255; https://doi.org/10.3390/inorganics11060255 - 09 Jun 2023

Cited by 1 | Viewed by 863

Abstract

Binuclear diaminocarbene complexes, which form as a regioisomer mixture in the reaction between isocyanide–palladium(II) complex cis-[PdCl₂(CNXyl)₂] and 1,3-thiazol-2-amine, are able to exchange an anionic chloride ligand with other halides, such as Br or I. This process also affords [...] Read more.

Binuclear diaminocarbene complexes, which form as a regioisomer mixture in the reaction between isocyanide–palladium(II) complex cis-[PdCl₂(CNXyl)₂] and 1,3-thiazol-2-amine, are able to exchange an anionic chloride ligand with other halides, such as Br or I. This process also affords binuclear complexes as mixtures of kinetically and thermodynamically controlled regioisomers. In CDCl₃ solutions, we observed interconversion of kinetically and thermodynamically controlled regioisomers. The results of the DFT calculations revealed that in CHCl₃ solution, each pair of the isomers exhibited two different types of chalcogen bonding such as S···X or S···N; the presence of CBs for two complexes in the solid state was also proven through X-ray crystallographic study. Based on the combined experimental and theoretical data, it could be concluded that thermodynamic favorability for the formation of thermodynamically controlled regioisomers increases in the Cl < Br ≈ I row and correlate well with the energy difference between S···N and S···X (X = Cl, Br, I) chalcogen bonds in kinetically and thermodynamically controlled products. This means that it is possible to change the structure of metallocycles in binuclear diaminocarbene complexes by simply replacing one halide ligand with another. Full article

(This article belongs to the Special Issue Non-covalent Interactions in Coordination Chemistry)

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12 pages, 1520 KiB

Open AccessArticle

Basalt-Fiber-Reinforced Phosphorus Building Gypsum Composite Materials (BRPGCs): An Analysis on Their Working Performance and Mechanical Properties

by Lei Wu, Zhong Tao, Ronggui Huang, Zhiqi Zhang, Jinjin Shen and Weijie Xu

Inorganics 2023, 11(6), 254; https://doi.org/10.3390/inorganics11060254 - 09 Jun 2023

Viewed by 934

Abstract

The preparation of fiber-reinforced phosphorus building gypsum composite materials (FRPGCs) is an important approach to enlarge the utilization of phosphogypsum resources. Through reinforcing phosphorus building gypsum (PBG) with basalt fiber (BF), this article probes into the effects of the length and fiber content [...] Read more.

The preparation of fiber-reinforced phosphorus building gypsum composite materials (FRPGCs) is an important approach to enlarge the utilization of phosphogypsum resources. Through reinforcing phosphorus building gypsum (PBG) with basalt fiber (BF), this article probes into the effects of the length and fiber content of BF on the working performance and mechanical properties of basalt-fiber-reinforced phosphorus building gypsum composite materials (BRPGCs) and accesses the toughness of BRPGCs under bending loads using residual strength. The results showed that the addition of BF could significantly promote the mechanical properties of BRPGCs. However, due to the adverse effect of fibers on the working performance of BRPGCs, the fiber content was constrained. After adding 1.2% of 6 mm BF, the bending strength and compressive strength of FRPGCs reached maximum values of 10.98 MPa and 29.83 MPa, respectively. Under a bending load, BRPGCs exhibited an apparent ductile behavior. The P-δ curve presented five stages, with an evident phase of strength stability after cracking. A larger fiber content was conducive to the toughness of BRPGCs. When 1.6% of 6 mm BF was added, the residual strength of FRPGCs could reach 6.77 MPa. Full article

(This article belongs to the Special Issue 10th Anniversary of Inorganics: Inorganic Materials)

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15 pages, 3568 KiB

Open AccessArticle

Supramolecular Structure and Antimicrobial Activity of Ni(II) Complexes with s-Triazine/Hydrazine Type Ligand

by Eman M. Fathalla, Morsy A. M. Abu-Youssef, Mona M. Sharaf, Ayman El-Faham, Assem Barakat, Matti Haukka and Saied M. Soliman

Inorganics 2023, 11(6), 253; https://doi.org/10.3390/inorganics11060253 - 09 Jun 2023

Cited by 2 | Viewed by 1376

Abstract

The two complexes, [Ni(DPPT)₂](NO₃)₂*1.5H₂O (1) and [Ni(DPPT)(NO₃)Cl].EtOH (2), were synthesized using the self-assembly of (E)-2,4-di(piperidin-1-yl)-6-(2-(1-(pyridin-2-yl)ethylidene)hydrazinyl)-1,3,5-triazine (DPPT) with Ni(NO₃)₂*6H₂O in [...] Read more.

The two complexes, [Ni(DPPT)₂](NO₃)₂*1.5H₂O (1) and [Ni(DPPT)(NO₃)Cl].EtOH (2), were synthesized using the self-assembly of (E)-2,4-di(piperidin-1-yl)-6-(2-(1-(pyridin-2-yl)ethylidene)hydrazinyl)-1,3,5-triazine (DPPT) with Ni(NO₃)₂*6H₂O in the absence and presence of NiCl₂*6H₂O, respectively. In both cases, the neutral tridentate DPPT ligand is found coordinated to the Ni(II) via three N-atoms from the hydrazone, pyridine and s-triazine rings. Hence, the homoleptic complex 1 has a NiN₆ hexa-coordination environment while two NO₃⁻ are counter anions in addition to one-and-a-half crystallized hydration water molecules are found acting as an outer sphere. The heteroleptic complex 2 has a NiN₃O₂Cl coordination sphere where the coordination environment of the Ni(II) is completed by one bidentate nitrate and one chloride ion leading to a neutral inner sphere while the outer sphere contains one crystallized ethanol molecule. Both complexes have distorted octahedral coordination environments around the Ni(II) ion. Using Hirshfeld analysis, the intermolecular contacts H…H and O…H in 1 and the Cl…H, O…H, N…H, H…H, C…H and C…C in 2 are found to be the most important for crystal stability. The antimicrobial activity of complexes 1 and 2 was assessed against different bacterial and fungal strains, and the results were compared with the free ligand as well as the antibacterial (Gentamycin) and antifungal (Ketoconazole) positive controls. Both Ni(II) complexes are better antibacterial and antifungal agents than the free ligand. Interestingly, both Ni(II) complexes have similar antifungal activity against C. albicans compared to Ketoconazole. Full article

(This article belongs to the Special Issue 10th Anniversary of Inorganics: Coordination Chemistry)

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23 pages, 3950 KiB

Open AccessReview

Copper-Based Antibiotic Strategies: Exploring Applications in the Hospital Setting and the Targeting of Cu Regulatory Pathways and Current Drug Design Trends

by Aixa M. Orta-Rivera, Yazmary Meléndez-Contés, Nataniel Medina-Berríos, Adriana M. Gómez-Cardona, Andrés Ramos-Rodríguez, Claudia Cruz-Santiago, Christian González-Dumeng, Janangelis López, Jansteven Escribano, Jared J. Rivera-Otero, Josean Díaz-Rivera, Sebastián C. Díaz-Vélez, Zulemaría Feliciano-Delgado and Arthur D. Tinoco

Inorganics 2023, 11(6), 252; https://doi.org/10.3390/inorganics11060252 - 08 Jun 2023

Viewed by 1937

Abstract

Classical antibacterial drugs were designed to target specific bacterial properties distinct from host human cells to maximize potency and selectivity. These designs were quite effective as they could be easily derivatized to bear next-generation drugs. However, the rapid mutation of bacteria and their [...] Read more.

Classical antibacterial drugs were designed to target specific bacterial properties distinct from host human cells to maximize potency and selectivity. These designs were quite effective as they could be easily derivatized to bear next-generation drugs. However, the rapid mutation of bacteria and their associated acquired drug resistance have led to the rise of highly pathogenic superbug bacterial strains for which treatment with first line drugs is no match. More than ever, there is a dire need for antibacterial drug design that goes beyond conventional standards. Taking inspiration by the body’s innate immune response to employ its own supply of labile copper ions in a toxic attack against pathogenic bacteria, which have a very low Cu tolerance, this review article examines the feasibility of Cu-centric strategies for antibacterial preventative and therapeutic applications. Promising results are shown for the use of Cu-containing materials in the hospital setting to minimize patient bacterial infections. Studies directed at disrupting bacterial Cu regulatory pathways elucidate new drug targets that can enable toxic increase of Cu levels and perturb bacterial dependence on iron. Likewise, Cu intracellular chelation/prochelation strategies effectively induce bacterial Cu toxicity. Cu-based small molecules and nanoparticles demonstrate the importance of the Cu ions in their mechanism and display potential synergism with classical drugs. Full article

(This article belongs to the Special Issue Weaponizing Metals against Pathogenic Bacterial Superbugs)

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11 pages, 4029 KiB

Open AccessArticle

Hydrogen Storage Properties of Economical Graphene Materials Modified by Non-Precious Metal Nickel and Low-Content Palladium

by Yiwen Chen, Habibullah, Guanghui Xia, Chaonan Jin, Yao Wang, Yigang Yan, Yungui Chen, Xiufang Gong, Yuqiu Lai and Chaoling Wu

Inorganics 2023, 11(6), 251; https://doi.org/10.3390/inorganics11060251 - 08 Jun 2023

Cited by 3 | Viewed by 1761

Abstract

Ni/Pd co-modified graphene hydrogen storage materials were successfully prepared by a solvothermal method using NiCl₂·6H₂O and Pd(OAc)₂ and reduced graphene oxide (rGO). By adjusting the hydrothermal temperature, Pd–Ni is successfully alloyed, and the size of the obtained nanoparticles [...] Read more.

Ni/Pd co-modified graphene hydrogen storage materials were successfully prepared by a solvothermal method using NiCl₂·6H₂O and Pd(OAc)₂ and reduced graphene oxide (rGO). By adjusting the hydrothermal temperature, Pd–Ni is successfully alloyed, and the size of the obtained nanoparticles is uniform. The electronic structure of Pd was changed by alloying, and the center of the D-band moved down, which promoted the adsorption of hydrogen. The NiPd-rGO-180 sample, in which 180 represents the solvothermal temperature in centigrade (°C), has the highest hydrogen storage capacity of 2.65 wt% at a moderate condition (RT/4MPa). The excellent hydrogen storage performance benefits from the synergistic hydrogen spillover effect of Pd–Ni bimetal. The calculated hydrogen adsorption energies of Ni₂Pd₂-rGO are within the ideal range (−0.20 to −0.60 eV) of hydrogen ads/desorption; however, the introduction of substrate defects and the cluster orientation alter the hydrogen adsorption energy. This work provides an effective reference for the design and optimization of carbon-based hydrogen storage materials. Full article

(This article belongs to the Special Issue 10th Anniversary of Inorganics: Inorganic Materials)

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3 pages, 1501 KiB

Open AccessEditorial

Recent Progress in Coordination Chemistry

by Peter Segľa and Ján Pavlik

Inorganics 2023, 11(6), 250; https://doi.org/10.3390/inorganics11060250 - 08 Jun 2023

Viewed by 798

Abstract

The following Special Issue of Inorganics is based on the discussions initiated at the International Conference on Coordination and Bioinorganic Chemistry (ICCBIC), which has been organized and held biennially since 1964 [...] Full article

(This article belongs to the Special Issue Recent Progress in Coordination Chemistry)

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19 pages, 8756 KiB

Open AccessArticle

The Influence of Ag⁺/Ti⁴⁺ Ratio on Structural, Optical and Photocatalytic Properties of MWCNT–TiO₂–Ag Nanocomposites

by Ramona-Crina Suciu, Mioara Zagrai, Adriana Popa, Dana Toloman, Camelia Berghian-Grosan, Cristian Tudoran and Maria Stefan

Inorganics 2023, 11(6), 249; https://doi.org/10.3390/inorganics11060249 - 07 Jun 2023

Cited by 2 | Viewed by 1062

Abstract

In this paper, we propose a simple procedure to obtain multi-walled carbon nanotubes (MWCNTs) decorated with TiO₂–Ag nanoparticles (MWCNT–TiO₂–Ag). The MWCNTs were decorated with TiO₂–Ag via combined functionalization with –OH and –COOH groups and a polymer-wrapping technique [...] Read more.

In this paper, we propose a simple procedure to obtain multi-walled carbon nanotubes (MWCNTs) decorated with TiO₂–Ag nanoparticles (MWCNT–TiO₂–Ag). The MWCNTs were decorated with TiO₂–Ag via combined functionalization with –OH and –COOH groups and a polymer-wrapping technique using poly(allylamine)hydrochloride (PAH). TiO₂-modified Ag nanoparticles were synthesized via the Pechini method using a mixture of acetylacetonate-modified titanium (IV) isopropoxide with silver nitrate (with Ag⁺/Ti⁴⁺ atomic ratios of 0.5%, 1.0%, 1.5%, 2.0%, and 2.5%) and L(+)-ascorbic acid as reducing agents. XRD analysis revealed the formation of nanocomposites containing CNT, anatase TiO₂, and Ag. The presence of nanoparticles on the MWCNT surfaces was determined using TEM. The morphology of the TiO₂–Ag nanoparticles on the MWCNT surfaces was also determined using TEM. UV–Vis investigations revealed that an increase in the ratio between Ag⁺ and Ti⁴⁺ decreased the band gap energy of the samples. The characteristic vibrations of the TiO₂, Ag, and C atoms of the graphite were identified using Raman spectroscopy. The photocatalytic activity of the MWCNT–TiO₂–Ag nanocomposite was assessed by examining the degradation of Allura Red (E129) aqueous solution under UV irradiation. The dye photodegradation process followed a pseudo-first-order kinetic with respect to the Langmuir–Hinshelwood reaction mechanism. The spin-trapping technique evidenced that •O²⁻ was the main species generated responsible for the Allura Red degradation. Full article

(This article belongs to the Special Issue Optoelectronic Properties of Metal Oxide Semiconductors)

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12 pages, 3916 KiB

Open AccessArticle

Synthesis, Structure and Bonding of the Tungstaboranes [Cp*W(CO)₂B₃H₈] and [(Cp*W)₃(CO)₂B₄H₇]

by Stutee Mohapatra, Sourav Gayen, Sampad Shyamal, Jean-François Halet and Sundargopal Ghosh

Inorganics 2023, 11(6), 248; https://doi.org/10.3390/inorganics11060248 - 07 Jun 2023

Cited by 1 | Viewed by 1121

Abstract

The structure and bonding of two novel tungstaboranes which were synthesized using diverse synthetic methods are described. (i) The room-temperature photolysis of [Cp*W(CO)₃Me] with [BH₃·SMe₂] led to the isolation of the hydrogen-rich tungstaborane [Cp*W(CO)₂B₃ [...] Read more.

The structure and bonding of two novel tungstaboranes which were synthesized using diverse synthetic methods are described. (i) The room-temperature photolysis of [Cp*W(CO)₃Me] with [BH₃·SMe₂] led to the isolation of the hydrogen-rich tungstaborane [Cp*W(CO)₂B₃H₈] (1). Its geometry consists of an arachno butterfly core similar to tetraborane(10) and obeys the Wade-Mingos electron counting rules (n vertices, n + 3 skeletal electron pairs (seps)). (ii) Further, the tungstaborane [(Cp*W)₃(μ-H)₂(μ₃-H)(μ-CO)₂B₄H₄] (4) was isolated by thermolysis reaction of a tungsten intermediate, obtained by low temperature reaction of [Cp*WCl₄] and [LiBH₄·THF] with [Cr(CO)₅·THF]. Compound 4 which seems to have formed by replacement of a BH unit in [(Cp*W)₂B₅H₉] by the isoelectronic fragment {Cp*W(CO)₂}, adopts an oblato-nido hexagonal-bipyramidal core (n vertices, n–1 seps). Both compounds were characterized using multinuclear NMR, IR spectroscopy, mass spectrometry as well as single crystal X-ray diffraction analysis. In addition, density functional theory (DFT) calculations were performed in order to elucidate their bonding and electronic structures. Full article

(This article belongs to the Special Issue Fifth Element: The Current State of Boron Chemistry)

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16 pages, 4189 KiB

Open AccessArticle

Synthesis of CuAl-LDHs by Co-Precipitation and Mechanochemical Methods and Selective Hydrogenation Catalysts Based on Them

by Olga B. Belskaya, Elena N. Terekhova, Oksana V. Gorbunova, Ivan V. Muromtsev, Mikhail V. Trenikhin, Aleksei N. Salanov and Vladimir A. Likholobov

Inorganics 2023, 11(6), 247; https://doi.org/10.3390/inorganics11060247 - 07 Jun 2023

Viewed by 1305

Abstract

The paper presents the results of the synthesis and study of CuAl layered double hydroxides (LDHs) as well as their application as catalysts for the selective hydrogenation of crotonaldehyde. Phase-homogeneous LDHs were obtained by co-precipitation and mechanochemical methods, and critical parameters ensuring the [...] Read more.

The paper presents the results of the synthesis and study of CuAl layered double hydroxides (LDHs) as well as their application as catalysts for the selective hydrogenation of crotonaldehyde. Phase-homogeneous LDHs were obtained by co-precipitation and mechanochemical methods, and critical parameters ensuring the formation of the target product were identified. In the case of coprecipitation, the formation of LDH is most affected by the pH of the reaction medium and the CO₃²⁻/Al³⁺ ratio. The optimal CO₃²⁻/Al³⁺ ratio is ca. 0.5–0.8 and pH 9.5–10.0. When mechanochemical synthesis is used, at 500 m·s⁻² and 60 min, it is possible to obtain a single-phase CuAl LDH, whereas at higher energies, LDH is destroyed. The mechanochemical method makes it possible not only to reduce the synthesis time and the amount of alkaline wash water but also to obtain more dispersed copper particles with a higher hydrogenating activity. The conversion of 2-butenal (T = 80 °C, P = 0.5 MPa, 180 min, ethanol) for this sample was 99.9%, in contrast to 50.5% for the catalyst obtained by co-precipitation. It is important that, regardless of the conversion, both catalysts showed high selectivity (S = 90–95%) for the double bond hydrogenation. Full article

(This article belongs to the Special Issue Layered Double Hydroxides for Catalytic Applications)

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16 pages, 4232 KiB

Open AccessArticle

The Effect of the Saudi Haloxylon ammodendron Shrub on Silver Nanoparticles: Optimal Biosynthesis, Characterization, Removability of Mercury Ions, Antimicrobial and Anticancer Activities

by Ahmed N. Al-Hakimi, Tahani M. Alresheedi and Reema A. Albarrak

Inorganics 2023, 11(6), 246; https://doi.org/10.3390/inorganics11060246 - 07 Jun 2023

Cited by 1 | Viewed by 1355

Abstract

This research provides a sustainable way to treat water by removing heavy metal hazards (mercury ion) and biological pollutants (several strains of bacteria and fungi) through the eco-friendly synthesis of silver nanoparticles using the ethanol extract of the Saudi Haloxylon ammodendron shrub, which [...] Read more.

This research provides a sustainable way to treat water by removing heavy metal hazards (mercury ion) and biological pollutants (several strains of bacteria and fungi) through the eco-friendly synthesis of silver nanoparticles using the ethanol extract of the Saudi Haloxylon ammodendron shrub, which is planted in the Qassim desert. Further, this work confirms that these nanoparticles could be used as anticancer materials. The optimization factors of the biosynthesis of silver nanoparticles were studied and obtained (volume ratio = 1:2, pH = 7.5, and temperature = 60 °C). The scanning electron microscope micrographs showed the spherical shape and the huge numbers of silver nanoparticles accumulated, while X-ray diffraction measurements gave the crystal size of these nanoparticles in the range of 10.64 nm. The application findings of these biofabricated silver nanoparticles demonstrated effective detection and removal of different concentrations of mercury ions (0–2500 ppm) from the polluted aqueous solutions. The work revealed that Haloxylon ammodendron extract enhanced the antibacterial and antifungal activities of silver nanoparticles against different strains of bacteria and fungi. As well, the anticancer activity examinations of these nanoparticles and the extract showed good and reasonable results. Full article

(This article belongs to the Special Issue Controlled Silver Nanostructures: Zero-Dimensional (0D), One-Dimensional (1D), Two-Dimensional (2D) and Three-Dimensional (3D))

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22 pages, 1166 KiB

Open AccessArticle

Chemical Bonding in the C₂ Molecule

by Alexander F. Sax

Inorganics 2023, 11(6), 245; https://doi.org/10.3390/inorganics11060245 - 06 Jun 2023

Viewed by 1510

Abstract

Bonding in the C₂ molecule is investigated with CAS(8,8) wave functions using canonical MOs. In a subsequent step, orthogonal atomic orbitals are constructed by localizing the CASSCF MOs on the two carbon atoms with an orthogonal transformation. This orbital transformation causes an [...] Read more.

Bonding in the C₂ molecule is investigated with CAS(8,8) wave functions using canonical MOs. In a subsequent step, orthogonal atomic orbitals are constructed by localizing the CASSCF MOs on the two carbon atoms with an orthogonal transformation. This orbital transformation causes an orthogonal transformation of the configuration state functions (CSF) spanning the function space of the singlet ground state of C₂. Instead of CSFs built from canonical MOs, one obtains CSFs of orthogonal deformed atomic orbitals (AO). This approach resembles the orthogonal valence bond (OVB) methods’ CSFs, which are very different from the conventional VB, based on non-orthogonal AOs. To become used to the different argumentation, the bonding situations in ethane (single bond), ethene (double bond), and the nitrogen molecule (triple bond) are also studied. The complex bonding situation in C₂ is caused by the possibility to excite an electron with a spin flip from the doubly occupied 2s AO into the 2p subshell, and the resulting high-spin

^{5} S_{u}

state of the carbon atom allows for a better reduction of the Pauli repulsion. However, the electron structure around the equilibrium distance does not allow one to say that C₂ in its ground state has a double, or triple, or even a quadruple bond. Full article

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11 pages, 2017 KiB

Open AccessArticle

New Insights into the Catalytic Activity of Second Generation Hoveyda–Grubbs Complexes Having Phenyl Substituents on the Backbone

by Assunta D’Amato, Annaluisa Mariconda and Pasquale Longo

Inorganics 2023, 11(6), 244; https://doi.org/10.3390/inorganics11060244 - 06 Jun 2023

Cited by 1 | Viewed by 1258

Abstract

One of the most effective synthetic pathways to produce unsaturated compounds and polymers, meant for both industrial and pharmaceutical applications, is olefin metathesis. These useful reactions are commonly promoted by ruthenium-based precatalysts, namely the second-generation Grubbs’ catalyst (GII) and complexes bearing a styrenyl [...] Read more.

One of the most effective synthetic pathways to produce unsaturated compounds and polymers, meant for both industrial and pharmaceutical applications, is olefin metathesis. These useful reactions are commonly promoted by ruthenium-based precatalysts, namely the second-generation Grubbs’ catalyst (GII) and complexes bearing a styrenyl ether ligand, referred to as the second-generation Hoveyda–Grubbs’ catalyst (HGII). By altering the steric and electronic characteristics of substituents on the backbone and/or on the nitrogen atoms of the NHC ligand, it is possible to increase the reactivity and stability of second-generation ruthenium catalysts. The synthesis of an HG type II complex bearing two anti-phenyl backbone substituents (anti-HGII_Ph-Mes) with mesityl N-substituents is reported. The catalytic performances of the new complex were investigated in standard ring-closing metathesis (RCM) and ring-opening metathesis polymerization (ROMP) and compared to those of the analogue complex syn-HGII_Ph-Mes and to the classic HGII complex. A thorough analysis of the temperature dependence of the performances, along with a detailed comparison with the commercially available HGII, is conducted. The HGII_Ph-Mes complexes are more thermally stable than their parent HGII, as shown by the fact that their activity in the ROMP of 5-ethylidene-2-norbornene does not alter when the polymerization is carried out at room temperature after the complexes have been held at 180 °C for two hours, making them particularly interesting for materials applications. Full article

(This article belongs to the Special Issue N-Heterocyclic Carbene Metal Complexes: Synthesis, Properties and Applications)

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11 pages, 9833 KiB

Open AccessArticle

Hydrogen Release and Uptake of MgH₂ Modified by Ti₃CN MXene

by Xiantun Huang, Chenglin Lu, Yun Li, Haimei Tang, Xingqing Duan, Kuikui Wang and Haizhen Liu

Inorganics 2023, 11(6), 243; https://doi.org/10.3390/inorganics11060243 - 05 Jun 2023

Cited by 6 | Viewed by 1295

Abstract

MgH₂ has a high hydrogen content of 7.6 wt% and possesses good reversibility under normal conditions. However, pristine MgH₂ requires a high temperature above 300 °C to release hydrogen, with very slow kinetics. In this work, we utilized Ti₃CN [...] Read more.

MgH₂ has a high hydrogen content of 7.6 wt% and possesses good reversibility under normal conditions. However, pristine MgH₂ requires a high temperature above 300 °C to release hydrogen, with very slow kinetics. In this work, we utilized Ti₃CN MXene to reduce the operating temperature and enhance the kinetics of MgH₂. The initial temperature of MgH₂ decomposition can be lowered from 322 °C for pristine MgH₂ to 214 °C through the employment of Ti₃CN. The desorbed MgH₂ + 7.5 wt% Ti₃CN can start absorption at room temperature, while the desorbed pristine MgH₂ can only start absorption at 120 °C. The employment of Ti₃CN can significantly improve the hydrogen release kinetics of MgH₂, with the desorption activation energy decreasing from 121 to 80 kJ mol⁻¹. Regarding thermodynamics, the desorption enthalpy changes of MgH₂ and MgH₂ + 7.5 wt% Ti₃CN were 79.3 and 78.8 kJ mol⁻¹, respectively. This indicates that the employment of Ti₃CN does not alter the thermal stability of MgH₂. Phase evolution studies through the use of X-ray diffraction and electron diffraction both confirm that Ti₃CN remains stable during the hydrogen release and uptake process of the composite. This work will help understand the impact of a transition metal carbonitride on the hydrogen storage of MgH₂. Full article

(This article belongs to the Special Issue State-of-the-Art and Progress in Metal-Hydrogen Systems)

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9 pages, 1249 KiB

Open AccessCommunication

Organomonophosphines in Pt(η³-X¹X²X³)(PR₃), (X = N¹, N², N³; S¹, S², S³; or Te¹, Te², Te³) Derivatives: Structural Aspects

by Milan Melník, Veronika Mikušová and Peter Mikuš

Inorganics 2023, 11(6), 242; https://doi.org/10.3390/inorganics11060242 - 03 Jun 2023

Cited by 3 | Viewed by 867

Abstract

This paper covers nineteen Pt(II) complexes of the composition Pt(η³-X¹X²X³)(PR₃), (X = N¹, N², N³; S¹, S², S³; or Te¹ [...] Read more.

This paper covers nineteen Pt(II) complexes of the composition Pt(η³-X¹X²X³)(PR₃), (X = N¹, N², N³; S¹, S², S³; or Te¹, Te², Te³). These complexes crystallized in three crystal classes: triclinic (eleven examples), monoclinic (six examples), and orthorhombic (two examples). Each tridentate ligand creates two metallocyclic rings with common N², S², or Te² donor ligands of the types N¹C₂N²C₂N³, N¹C₂N²NC₂N³, S¹C₂S²C₂S³, S¹C₃S²C₃S³, and Te¹CNTe²NCTe³. The homotridentate ligand with monodentate PR₃ ligand builds up a distorted square planar geometry about Pt(II) atoms. The degree of distortion ranges from 0.029 to 0.092, and the reason for the distortion is discussed. There is an example that contains two crystallographically independent molecules within the same crystal. This is a classic example of distortion isomerism. Full article

(This article belongs to the Section Inorganic Materials)

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14 pages, 3642 KiB

Open AccessArticle

Novel BODIPY Conjugates with Myrtenol: Design, Spectral Characteristics, and Possibilities for Practical Application

by Galina B. Guseva, Elena V. Antina, Mikhail B. Berezin, Liliya E. Nikitina, Ilmir R. Gilfanov, Roman S. Pavelyev, Svetlana A. Lisovskaya, Larisa L. Frolova, Olga V. Ostolopovskaya, Ilfat Z. Rakhmatullin, Vladimir V. Klochkov, Elena Y. Trizna and Airat R. Kayumov

Inorganics 2023, 11(6), 241; https://doi.org/10.3390/inorganics11060241 - 03 Jun 2023

Cited by 4 | Viewed by 1108

Abstract

The synthesis of new fluorescent probes, based on biocompatible luminophors and exhibiting various specificities, is intensively developed worldwide. Many luminophors contain a hydrophobic group that limits their application for cell staining under vital conditions. Herein, we report the synthesis of two BODIPY molecules— [...] Read more.

The synthesis of new fluorescent probes, based on biocompatible luminophors and exhibiting various specificities, is intensively developed worldwide. Many luminophors contain a hydrophobic group that limits their application for cell staining under vital conditions. Herein, we report the synthesis of two BODIPY molecules—BF₂-meso-(4-butan/pentanamido-N-(((1S,5R)-6,6-dimethylbicyclo [3.1.1]hept-2-en-2-yl)methyl)-N,N-dimethylpropan-1-aminium)-3,3′,5,5′-tetramethyl-2,2′-dipyrromethene bromides—designed as 10, 11 with a spacer of either four or three CH₂ groups in length, respectively. These molecules present conjugates of BODIPY luminophors with (+)-myrtenol via a quaternary ammonium group. Both terpene-BODIPY conjugates demonstrated high fluorescence efficiency in various solvents such as OctOH, DMSO and water, and were characterized by their stability at pH 1.65–9.18. The fusion of the myrtenol, a monocyclic terpene, to the BODIPY fluorophore in the meso-substituent facilitated their penetration into the filamentous fungi Fusarium solani, while impairing the binding of the latter with S. aureus, K. pneumoniae and P. aeruginosa. The additional quaternary ammonium group between the myrtenol and fluorophore moieties restored the bacterial cell-staining while it did not affect the staining of fungi. Finally, the BODIPY conjugate 11 was able to stain both Gram-positive and Gram-negative bacteria by its interaction with their cell wall (or the membrane), as well as penetrating into filamentous fungi F. solani and staining their mitochondria. Full article

(This article belongs to the Special Issue Synthesis and Innovative Biological Activity of Boron-Containing Compounds)

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9 pages, 2592 KiB

Open AccessArticle

Adsorption of Metal Atoms on SiC Monolayer

by Lei Jiang, Yanbo Dong and Zhen Cui

Inorganics 2023, 11(6), 240; https://doi.org/10.3390/inorganics11060240 - 30 May 2023

Cited by 2 | Viewed by 1119

Abstract

The electronic, magnetic, and optical behaviors of metals (M = Ag, Al, Au, Bi, Ca, Co, Cr, Cu, Fe, Ga, K, Li, Mn, Na, Ni) adsorbed on the SiC monolayer have been calculated based on density functional theory (DFT). The binding energy results [...] Read more.

The electronic, magnetic, and optical behaviors of metals (M = Ag, Al, Au, Bi, Ca, Co, Cr, Cu, Fe, Ga, K, Li, Mn, Na, Ni) adsorbed on the SiC monolayer have been calculated based on density functional theory (DFT). The binding energy results show that all the M-adsorbed SiC systems are stable. All the M-adsorbed SiC systems are magnetic with magnetic moments of 1.00 μ_B (Ag), 1.00 μ_B (Al), 1.00 μ_B (Au), 1.01 μ_B (Bi), 1.95 μ_B (Ca), 1.00 μ_B (Co), 4.26 μ_B (Cr), 1.00 μ_B (Cu), 2.00 μ_B (Fe), 1.00 μ_B (Ga), 0.99 μ_B (K), 1.00 μ_B (Li), 3.00 μ_B (Mn), and 1.00 μ_B (Na), respectively, except for the Ni-adsorbed SiC system. The Ag, Al, Au, Cr, Cu, Fe, Ga, Mn, and Na-adsorbed SiC systems become magnetic semiconductors, while Bi, Ca, Co, K, and Li-adsorbed SiC systems become semimetals. The Bader charge results show that there is a charge transfer between the metal atom and the SiC monolayer. The work function of the K-adsorbed SiC system is 2.43 eV, which is 47.9% lower than that of pristine SiC and can be used in electron-emitter devices. The Bi, Ca, Ga, and Mn-adsorbed SiC systems show new absorption peaks in the visible light range. These results indicate that M-adsorbed SiC systems have potential applications in the field of spintronic devices and solar energy conversion photovoltaic devices. Full article

(This article belongs to the Special Issue Advanced Inorganic Semiconductor Materials)

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15 pages, 3175 KiB

Open AccessArticle

Covalent Grafting of Eosin Y to the Giant Keplerate {Mo₁₃₂} through an Organosilicon Linker in Homogeneous Regime

by Andrey Denikaev, Grigory Kim, Evgeny Greshnyakov, Nikolai Moskalenko and Kirill Grzhegorzhevskii

Inorganics 2023, 11(6), 239; https://doi.org/10.3390/inorganics11060239 - 30 May 2023

Cited by 2 | Viewed by 1069

Abstract

The template effect of giant polyoxometalates (POM) shows promising results towards the supramolecular design of hybrid materials suitable for photocatalytic reactions. Here, we demonstrate a novel synthetic approach for covalently grafting the xanthene dye eosin Y (EY) to the nanoscale Keplerate POM {Mo [...] Read more.

The template effect of giant polyoxometalates (POM) shows promising results towards the supramolecular design of hybrid materials suitable for photocatalytic reactions. Here, we demonstrate a novel synthetic approach for covalently grafting the xanthene dye eosin Y (EY) to the nanoscale Keplerate POM {Mo₁₃₂} via an organosilicon linker (3-aminopropyltrimethoxysilane, APTMS) in a homogeneous regime. Using a phase transfer agent, tetrabutylammonium bromide, we solubilize the Keplerate POM modified with six {Si(CH₂)₃NH₂} groups, {Mo₁₃₂}@Si₆, in a series of organic solvents—acetonitrile, acetone, tetrahydrofuran, and dichloromethane—to perform post-functionalization by using an NHS-ester of EY. Both IR and Raman spectroscopy affirm the preservation of the POM’s structure and showcase an amide bond formation between POM and EY in the obtained conjugate {Mo₁₃₂}@Si₆@EY@TBA. Grafting’s success is observed through significant downfield shifting of EY’s aromatic protons’ signals on the ¹H NMR spectrum as compared to the spectra of EY and EY-NHS. The current synthetic approach enables us to exercise precise control of the stoichiometry in the POM-dye conjugates—1:1 for the POM-EY system—as confirmed by elemental analysis. Comprehensive photophysical analysis of {Mo₁₃₂}@Si₆@EY@TBA by means of UV-Vis and steady-state and time-resolved fluorescence measurements points to an existing strong interaction between molecular orbitals of EY and {Mo₁₃₂}, leading to a photoinduced electron transfer, partial fluorescence quenching, and elongation of the excited state’s lifetime. These findings demonstrate that using APTMS as an organosilicon linker in tandem with the Keplerate POM as a nanoscale template can be readily applied as a routine synthetic procedure for grafting various organic dyes or other organic molecules bearing a carboxylic group in their structure to the giant POM surface in a variety of aprotic organic solvents. Full article

(This article belongs to the Special Issue Advances in Polyoxometalates for Supramolecular Architecture, Biomimetics and Bioapplications)

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12 pages, 3812 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Improved Oxide Ion Conductivity of Hexagonal Perovskite-Related Oxides Ba₃W_1+xV_1−xO_8.5+x/2

by Yugo Kikuchi, Yuta Yasui, James R. Hester and Masatomo Yashima

Inorganics 2023, 11(6), 238; https://doi.org/10.3390/inorganics11060238 - 29 May 2023

Cited by 3 | Viewed by 1206

Abstract

Hexagonal perovskite-related oxides such as Ba₃WVO_8.5 have attracted much attention due to their unique crystal structures and significant oxide ion conduction. However, the oxide ion conductivity of Ba₃WVO_8.5 is not very high. Herein, we report new hexagonal [...] Read more.

Hexagonal perovskite-related oxides such as Ba₃WVO_8.5 have attracted much attention due to their unique crystal structures and significant oxide ion conduction. However, the oxide ion conductivity of Ba₃WVO_8.5 is not very high. Herein, we report new hexagonal perovskite-related oxides Ba₃W_1+xV_1−xO_8.5+x/2 (x = −0.1, −0.05, 0.05, 0.1, 0.25, 0.4, 0.5, 0.6, and 0.75). The bulk conductivity of Ba₃W_1.6V_0.4O_8.8 was found to be 21 times higher than that of the mother material Ba₃WVO_8.5 at 500 °C. Maximum entropy method (MEM) neutron scattering length density (NSLD) analyses of neutron diffraction data at 800 °C experimentally visualized the oxide ion diffusion pathways through the octahedral O2 and tetrahedral O3 sites in intrinsically oxygen-deficient layers. By increasing the excess W content x in Ba₃W_1+xV_1−xO_8.5+x/2, the excess oxygen content x/2 increases, which leads to more oxygen atoms at the O2 and O3 oxygen sites, a higher minimum NSLD on the O2–O3 path, and a higher level of conductivity. Another reason for the increased conductivity of Ba₃W_1.6V_0.4O_8.8 is the lower activation energy for oxide ion conduction, which can be ascribed to the longer (W/V)–O2 and (W/V)–O3 distances due to the substitution of V atoms with large-sized W species. The present findings open new avenues in the science and technology of oxide ion conductors. Full article

(This article belongs to the Special Issue Layered Perovskites: Synthesis, Properties and Structures)

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13 pages, 3160 KiB

Open AccessArticle

Effect of AST Atmosphere on Pt/C Electrocatalyst Degradation

by Kirill Paperzh, Elizaveta Moguchikh, Ilya Pankov, Sergey Belenov and Anastasia Alekseenko

Inorganics 2023, 11(6), 237; https://doi.org/10.3390/inorganics11060237 - 28 May 2023

Cited by 2 | Viewed by 1395

Abstract

The targeted development of novel stress testing protocols as well as the production of highly active and stable catalysts require abandoning a trial-and-error approach and transitioning to identifying the principal degradation mechanisms of electrocatalysts for PEMFCs under various conditions. Methodological aspects of research [...] Read more.

The targeted development of novel stress testing protocols as well as the production of highly active and stable catalysts require abandoning a trial-and-error approach and transitioning to identifying the principal degradation mechanisms of electrocatalysts for PEMFCs under various conditions. Methodological aspects of research related to both qualitative and quantitative assessment of the materials’ robustness against degradation and its mechanisms become the key issues. In this study, accelerated stress testing has been conducted in Ar and O₂ to identify the influence of the atmosphere on the degradation and durability mechanisms of the Pt/C catalysts. Initial and final parameters after the AST have been studied in detail by transmission electron microscopy and voltammetry using the rotating disk electrode technique. The Ostwald ripening (redeposition) of platinum particles has been established to be the predominant degradation mechanism during the testing in an O₂ atmosphere, this being the agglomeration of nanoparticles during the testing in Ar. An ultra-small size and a narrow size distribution of platinum nanoparticles, as well as their uniform spatial distribution over the surface of the carbon support, have been shown to allow both ORR activity to be increased and durability to be enhanced. Full article

(This article belongs to the Special Issue Nanostructured Platinum-Containing Electrocatalysts for Hydrogen Energy)

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11 pages, 2932 KiB

Open AccessArticle

Pt Nanoparticles Supported on Ultrathin Ni(OH)₂ Nanosheets for Highly Efficient Reduction of 4-Nitrophenol

by Jia-Lin Cui, Zhong-Liang Liu, Hui-Hui Li and Chun-Zhong Li

Inorganics 2023, 11(6), 236; https://doi.org/10.3390/inorganics11060236 - 28 May 2023

Viewed by 1157

Abstract

The synthesis of highly efficient heterogeneous catalysts with uniformly dispersed noble metal particles and a suitable size is crucial for various industrial applications. However, the high cost and rarity of noble metals limit their economic efficiency, making it essential to improve the catalytic [...] Read more.

The synthesis of highly efficient heterogeneous catalysts with uniformly dispersed noble metal particles and a suitable size is crucial for various industrial applications. However, the high cost and rarity of noble metals limit their economic efficiency, making it essential to improve the catalytic performance with lower noble metal loading. Herein, a two-step method was developed for the synthesis of uniformly dispersed ~3 nm Pt nanoparticles (NPs), strongly anchored on Ni(OH)₂ nanosheets (NSs), which was proven by adequate structural characterizations. XPS analysis demonstrated that Ni(OH)₂ NSs with abundant oxygen vacancies provided sufficient anchor sites for Pt NPs and prevented their agglomeration. The catalytic performance of Pt_n/Ni(OH)₂ (n (represents the addition amount of Pt precursors during the synthesis, μmol) = 5, 10, 15, and 20) NSs with controllable Pt loading were evaluated via the reduction of 4-nitrophenol to 4-aminophenol as a model reaction. The Pt₁₀/Ni(OH)₂ NSs exhibited the best activity and stability, with a reaction rate constant of 0.02358 s⁻¹ and negligible deterioration in ten reaction cycles. This novel synthetic method shows potentials for the synthesis of highly efficient noble-metal-supported catalysts for heterogeneous catalysis. Full article

(This article belongs to the Special Issue Metal Nanomaterials as Efficient Electrocatalysts)

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13 pages, 3957 KiB

Open AccessArticle

Precipitative Coating of Calcium Phosphate on Microporous Silica–Titania Hybrid Particles in Simulated Body Fluid

by Reo Kimura, Kota Shiba, Kanata Fujiwara, Yanni Zhou, Iori Yamada and Motohiro Tagaya

Inorganics 2023, 11(6), 235; https://doi.org/10.3390/inorganics11060235 - 28 May 2023

Cited by 1 | Viewed by 1137

Abstract

Titania and silica have been recognized as potential drug delivery system (DDS) carriers. For this application, controllable biocompatibility and the suppression of the initial burst are required, which can be provided by a calcium phosphate (CP) coating. However, it is difficult to control [...] Read more.

Titania and silica have been recognized as potential drug delivery system (DDS) carriers. For this application, controllable biocompatibility and the suppression of the initial burst are required, which can be provided by a calcium phosphate (CP) coating. However, it is difficult to control the morphology of a CP coating on the surface of carrier particles owing to the homogeneous nucleation of CP. In this study, we report the development of a CP-coating method that homogeneously corresponds to the shapes of silica–titania (SiTi) porous nanoparticles. We also demonstrate that controlled surface roughness of CP coatings could be achieved in SBF using SiTi nanoparticles with a well-defined spherical shape, a uniform size, and a tunable nanoporous structure. The precipitation of CP was performed on mono-dispersed porous SiTi nanoparticles with different Si/Ti molar ratios and pore sizes. The pore size distribution was found to significantly affect the CP coating in SBF immersion; the surfaces of the nanoparticles with bimodal pore sizes of 0.7 and 1.1–1.2 nm became rough after CP precipitation, while those with a unimodal pore size of 0.7 nm remained smooth, indicating that these two pore sizes serve as different nucleation sites that lead to different surface morphologies. Full article

(This article belongs to the Special Issue New Advances into Nanostructured Oxides, 2nd Edition)

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18 pages, 4394 KiB

Open AccessArticle

Synthesis, Structural Properties, and Resistance to High-Temperature Degradation of Perovskite Ceramics Based on Lanthanum–Strontium Ferrite

by Daryn B. Borgekov, Artem L. Kozlovskiy, Maxim V. Zdorovets and Dmitriy I. Shlimas

Inorganics 2023, 11(6), 234; https://doi.org/10.3390/inorganics11060234 - 28 May 2023

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Abstract

This work is dedicated to the study of the properties of perovskite ceramics based on lanthanum–strontium ferrite, and to the evaluation of their resistance to long-term thermal aging. As a method for obtaining perovskite ceramics, the method of solid-phase mechanochemical grinding and consequent [...] Read more.

This work is dedicated to the study of the properties of perovskite ceramics based on lanthanum–strontium ferrite, and to the evaluation of their resistance to long-term thermal aging. As a method for obtaining perovskite ceramics, the method of solid-phase mechanochemical grinding and consequent thermal annealing of the resulting mixtures was chosen. The novelty of the study consists in the assessment of the phase transformation dynamics in lanthanum–strontium ferrite-based ceramics in relation to the annealing temperature, alongside the study of the effect of the phase composition of ceramics on the resistance to high-temperature aging, which is characteristic of the operating modes of these ceramics as materials for solid oxide fuel cells. To study the properties, the methods of scanning electron microscopy, energy dispersive analysis, and scanning electron microscopy were applied. Pursuant to the outcome of elemental analysis, it was established that no impurity inclusions appear in the ceramic structure during the synthesis, and a growth in the annealing temperature results into a decline in the grain size and a growth in their density. During the analysis of the acquired X-ray diffraction patterns, it was found that a growth in the annealing temperature above 500 °C results in phase transformations of the LaFeO₃/SrFe₂O₄ → La_0.3Sr_0.7FeO₃/LaSr₂FeO₈/La₃FeO₆ type, followed by structural ordering and a decline in deformation distortions with a growth in the annealing temperature. An analysis of the conductive properties of ceramics has established that the dominance of the La_0.3Sr_0.7FeO₃ phase in the structure results in a growth in conductivity and a decline in resistance. Life tests for degradation resistance have shown that for three-phase ceramics, the rate of degradation and amorphization is significantly lower than for two-phase ceramics. Full article

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Inorganics, Volume 11, Issue 6 (June 2023) – 40 articles

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