Inorganics, Volume 12, Issue 3 (March 2024) – 31 articles

The aromatic character of silolyl and germolyl anions markedly depends on the substituents in the 2,5-positions; carbon-substituted derivatives are nonaromatic, whereas silyl-substituted ones tend to exhibit an aromatic character. However, only carbon-substituted derivatives have been reported for stannolyl anions. In this study, we present the synthesis and structure of a 2,5-disilylated stannolyl anion. Transmetalation of a 2,5-disilyl-1-zirconacyclopentadiene with SnCl₄ gave a dichlorostannole 1, which reacted with potassium tris(trimethylsilyl)silanide to introduce a bulky silyl group on the tin atom. Reduction of the 1-chloro-1-silylstannole 2 with lithium generated the lithium salt of the desired stannolyl anion 3 that adopts an η¹-coordination to the lithium atom. We concluded that the stannolyl anion 3 is nonaromatic based on the pyramidalized tin center and the C–C bond alternation in the five-membered ring as well as the NMR properties. Full article

Vitamin B₁₂ (cyanocobalamin) is an essential nutrient with very low bioavailability. Compared with normal cells, tumor cells show an increased demand for vitamin B₁₂ to support their abnormal proliferation, which is a feature that can be exploited for the tumor-specific delivery of therapeutic and/or diagnostic agents by functionalizing vitamin B₁₂ with suitable metallodrugs and/or luminescent probes. In this context, we report on the design of fluorescent vitamin B₁₂–metal conjugates of the type [FLUO–B₁₂–{M}] in which cyanocobalamin is functionalized at the 5′-site of the ribose unit with a fluorophore (FLUO: rhodamine 6G), whereas the Co(III)–cyano moiety is N-coordinated to a metal-based anticancer scaffold ({M}: Pt(II) substrate bearing enantiopure phenylamino-oxime ligands derived from R- or S-limonene). Two novel fluorescent cyanocobalamin–platinum(II) derivatives and their corresponding non-fluorescent counterparts were successfully generated and fully characterized, including the evaluation of their lipophilicity and luminescent properties. Although they exhibit low antiproliferative activity (IC₅₀ = 40–70 μM), both fluorescent vitamin B₁₂–platinum(II) conjugates showed an enhanced capability to inhibit cell viability compared with the inactive metal precursors and the non-fluorescent vitamin B₁₂–platinum(II) analogues, confirming the beneficial effect of functionalization with the rhodamine 6G scaffold not only for imaging purposes but also with the aim of improving their biological activity. Full article

Oxynitrides such as LaTa(O,N)₃ are attractive materials as photoelectrodes for photoelectrocatalytic solar water splitting. The potential anionic ordering in their perovskite-type structure has been shown to impact the materials’ properties. Given the importance attributed to it, the present study reports a detailed experimental analysis supported by simulations of the anionic ordering of La_1−xY_xTa(O,N)₃. The influence of O/N and yttrium content on the anionic order was assessed. Neutron diffraction analysis was performed on four different nominal compositions—LaTaON₂, LaTaO₂N, La_0.9Y_0.1TaON₂, and La_0.9Y_0.1TaO₂N—at 10 K and 300 K to study potential long-range ordering. Neutron pair distribution function (PDF) analysis was performed on all samples at 10 K and on non-Y-substituted samples at 300 K to evaluate short-range ordering. There was no evidence of long-range O/N order in any of the compounds. In contrast, at a short range (1.5 Å ≤ r < 6 Å), a Pnma (a⁻b⁺a⁻) tilting pattern and local cis-ordering of the anions were seen. The latter faded rapidly, leaving the Pnma tilting pattern in a 6 Å ≤ r ≤ 11 Å range. At higher distances, the PDF analysis agreed with the Imma (a⁻b⁰a⁻) O/N disordered long-range structure. As the O/N content changed, not much difference in behavior was observed. Yttrium substitution introduced some disorder in the structure; nonetheless, it showed marginal influence on octahedral tilting and anionic ordering. Full article

There is currently much interest in avoiding precious metals in catalysis. The development of nickel catalysts to replace palladium in the Mizoroki–Heck reaction is a relevant case in this line of research, since both elements share many chemical features. This contribution focuses on β–phenyl (β–Ph) elimination in alkyl—nickel complexes. This is the microscopic reverse of olefin insertion (or carbometallation), a fundamental step in the Heck cycle that is usually considered irreversible and selectivity-determining. However, the potential reversibility of carbometallation is generally concealed by the facile β–hydrogen (β–H) elimination that follows. Where β–hydrogen elimination is hindered, β–aryl elimination may ensue. We have previously shown that cationic 2–methyl–2–phenylpropyl (neophyl) palladium complexes supported by bidentate ligands experience β–Ph elimination, which can be seen as an example of olefin de-insertion. In this contribution, we report that β–Ph elimination can also occur in their nickel analogs, in which case fast hydrolyses of the resulting phenyl product can follow the reaction. We investigated the mechanism of these processes and compared their feasibility for nickel and palladium catalysts using DFT calculations. These results are relevant information for the design of nickel-based catalysts for the Heck reaction. Full article

Cobalt-free manganese-based lithium-rich layered oxides (LLOs) have garnered research attention as prospective lithium-ion cathode materials owing to their large specific capacity and low price. However, their large-scale application is hindered by their low Coulombic efficiency, poor cycling performance, voltage attenuation, and structural phase transition. To address these issues, the LLO structure is modified via Ti doping at the manganese site herein. Ti-doped Li_1.2Mn_0.6−xTi_xNi_0.2O₂ (x = 0, 0.03, 0.05, 0.10, and 0.15) is prepared using the high-temperature solid-state method. The Ti-doped Li_1.2Mn_0.6Ni_0.2O₂ is calculated via first principles. The results show that Ti⁴⁺ doping improves the cycle stability and rate performance of Li_1.2Mn_0.6Ni_0.2O₂. Electrochemical test results show that the sample exhibits enhanced electrochemical performance when the Ti doping amount is 0.05. The discharge specific capacity at 0.1C is 210.4 mAh·g⁻¹, which reaches 191.1 mAh·g⁻¹ after 100 cycles, with a capacity retention rate of 90.7%. This study proves the feasibility of using cheap cobalt-free LLOs as cathode materials for LIBs and provides a novel system for exploiting low-cost and high-performance cathode materials. Full article

With the rapid growth of data storage, traditional von Neumann architectures and silicon-based storage computing technologies will reach their limits and fail to meet the storage requirements of ultra-small size, ultra-high density, and memory computing. Memristors have become a strong competitor in next generation memory technology because of their advantages such as simple device structure, fast erase speed, low power consumption, compatibility with CMOS technology, and easy 3D integration. The resistive medium layer is the key to achieving resistive performance; hence, research on memristors mainly focuses on the resistive medium layer. This paper begins by elucidating the fundamental concepts, structures, and resistive-switching mechanisms of memristors, followed by a comprehensive review of how different resistive storage materials impact memristor performance. The categories of memristors, the effects of different resistive materials on memristors, and the issues are described in detail. Finally, a summary of this article is provided, along with future prospects for memristors and the remaining issues in the large-scale industrialization of memristors. Full article

In this study, dinuclear and tetranuclear arene ruthenium porphyrins were synthesized and assessed for their potential as photosensitizers (PSs) in photodynamic therapy (PDT) using the Colo205 colon cancer cell line as a model system. Reactive oxygen species (ROS) production, cellular uptake, impact on cell viability, and mechanisms of cell death induced by the synthesized compounds were comprehensively investigated. Our results revealed that the number of arene ruthenium units, as well as zinc (Zn) metalation of the porphyrin core, significantly influenced ROS production and increased it two-folds compared to the Zn-free analogs. The uptake of tetra-substituted Zn-porphyrins by the cancer cells increased to 2.8 nmol/10⁶ cells compared to 0.6 nmol/10⁶ cells of the disubstituted Zn-free and Zn-chelating porphyrins. The anticancer photo-activity of the complexes, where the percentage of metabolic activity of disubstituted Zn-porphyrins decreased to 26% when Zn was inserted, was compared to disubstituted Zn-free analogs. A further decrease in metabolic activity was observed, when the number of arene ruthenium units increased in the tetra-substituted Zn-porphyrins and tetra-substituted Zn-free compounds, reaching 4% and 14% respectively. Moreover, the percentage of apoptotic cell deaths increased to 40% when Zn was inserted into disubstituted porphyrins, compared to disubstituted Zn-free analog, and 50% when the number of arene ruthenium units increased. Overall, the tetra-substituted Zn chelating porphyrins exhibited the highest PDT efficiency, followed by the di-substituted Zn-porphyrins. These findings underscore the importance of structural design in optimizing the efficacy of arene ruthenium porphyrins as PSs for PDT, offering valuable insights for the development of targeted cancer therapeutics. Full article

Eco-friendly magnesium-based thermoelectric materials have recently attracted significant attention in green refrigeration technology and wasted heat recovery applications due to their cost effectiveness, non-toxicity, and earth abundance. The energy conversion efficiency of these thermoelectric materials is controlled by a dimensionless thermoelectric figure of merit (TFM), which depends on thermal and electrical conductivity. The independent tuning of the electrical and thermal properties of these materials for TFM enhancement is challenging. The improvement in the TFM of magnesium thermoelectric materials through scattering and structural engineering is experimentally challenging, especially if multiple elements are to be incorporated at different concentrations and at different doping sites. This work models the TFM of magnesium-based thermoelectric materials with the aid of single-hidden-layer extreme learning machine (ELM) and hybrid genetic-algorithm-based support vector regression (GSVR) algorithms using operating absolute temperature, elemental ionic radii, and elemental concentration as descriptors. The developed TFM-G-GSVR model (with a Gaussian mapping function) outperforms the TFM-S-ELM model (with a sine activation function) using magnesium-based thermoelectric testing samples with improvements of 17.06%, 72%, and 73.03% based on correlation coefficient (CC), root mean square error (RMSE), and mean absolute error (MAE) assessment metrics, respectively. The developed TFM-P-GSVR (with a polynomial mapping function) also outperforms TFM-S-ELM during the testing stage, with improvements of 14.59%, 55.31%, and 62.86% using CC, RMSE, and MAE assessment metrics, respectively. Also, the developed TFM-G-ELM model (with a sigmoid activation function) shows superiority over the TFM-S-ELM model with improvements of 14.69%, 79.52%, and 83.82% for CC, RMSE, and MAE assessment yardsticks, respectively. The dependence of some selected magnesium-based thermoelectric materials on temperature and dopant concentration on TFM was investigated using the developed model, and the predicted patterns align excellently with the reported values. This unique performance demonstrated that the developed intelligent models can strengthen room-temperature magnesium-based thermoelectric materials for industrial and technological applications in addressing the global energy crisis. Full article

Human society annually produces nearly 100 billion gallons of wastewater, containing approximately 3600 GWh of energy. This study introduces a proof of concept utilizing graphene materials to extract and instantly store this energy. A hybrid device, mimicking a microbial fuel cell, acts as both a battery and supercapacitor. Wastewater serves as the electrolyte, with indigenous microorganisms on the graphene electrode acting as biocatalysts. The device features a capacitive electrode using a 3D nickel foam modified with a plasma-exfoliated graphene mixture. Compared to controls, the Gr/Ni configuration shows a 150-fold increase in power output (2.58 W/m²) and a 48-fold increase in current density (12 A/m²). The Gr/Ni/biofilm interface demonstrates outstanding charge storage capability (19,400 F/m²) as confirmed by electrochemical impedance spectroscopy. Microscopy, spectroscopy, and electrochemical tests were employed to elucidate the superior performance of Gr/Ni electrodes. Ultimately, the capacitive energy extracted from wastewater can power small electrical equipment in water infrastructure, addressing energy needs in remote regions without access to a typical power grid. Full article

Currently, a promising direction of study is the use of biologically active coordination compounds in the pharmacopoeia and the creation of effective bactericidal drugs, biomaterials, and enzyme modulators on that basis. The paper considers a coordination germanium compound with 2-amino-3-hydroxybutanoic acid. The prospects for the use of the compound in medicine are outlined. This work is aimed at solving the problems regarding the synthesis of biologically active compounds with a wide spectrum of actions. The structure and composition of the coordination compound have been established through calculation and experimental methods. The biocidal (bactericidal and fungicidal) activity of germanium-containing compounds against a number of bacteria and microscopic fungi has been studied. Using the quantum-chemical method with density functional theory (DFT, B3LYP/6–311++G(2d,2p)), the theoretical IR spectrum of the compound was calculated. The structure of the coordination compound and the structure of the intermediates at all stages of the synthesis process were established by calculation. Full article

The study of small synthetic models for the highly selective removal of uranyl ions from seawater with amidoxime-containing materials is a valuable means to enhance their recovery capacity, leading to better extractants. An important issue in such efforts is to design bifunctional ligands and study their reactions with trans-{UO₂}²⁺ in order to model the reactivity of polymeric sorbents possessing both amidoximate and another adjacent donor site on the side chains of the polymers. In this work, we present our results concerning the reactions of uranyl and pyrimidine-2-amidoxime, a ligand possessing two pyridyl nitrogens near the amidoxime group. The 1:2:2 {UO₂}²⁺/pmadH₂/external base (NaOMe, Et₃N) reaction system in MeOH/MeCN provided access to complex [UO₂(pmadH)₂(MeOH)₂] (1) in moderate yields. The structure of the complex was determined by single-crystal X-ray crystallography. The U^VI atom is in a distorted hexagonal bipyramidal environment, with the two oxo groups occupying the trans positions, as expected. The equatorial plane consists of two terminal MeOH molecules at opposite positions and two N,O pairs of two deprotonated η² oximate groups from two 1.11000 (Harris notation) pmadH⁻ ligands; the two pyridyl nitrogen atoms and the –NH₂ group remain uncoordinated. One pyridyl nitrogen of each ligand is the acceptor of one strong intramolecular H bond, with the donor being the coordinated MeOH oxygen atom. Non-classical C_aromatic-H⋯X (X=O, N) intermolecular H bonds and π–π stacking interactions stabilize the crystal structure. The complex was characterized by IR and Raman spectroscopies, and the data were interpreted in terms of the known structure of 1. The solid-state structure of the complex is not retained in DMSO, as proven via ¹H NMR and UV/Vis spectroscopic techniques as well as molar conductivity data, with the complex releasing neutral pmadH₂ molecules. The to-date known coordination chemistry of pmadH₂ is critically discussed. An attempt is also made to discuss the technological implications of this work. Full article

We have designed an excellent visible-light-driven and high-performance photocatalyst with a Ag-Cu₂O-ZnO nanowire heterostructure in our work by combining the hydrothermal approach with plasma–liquid technology. The structural and morphological characteristics and optical properties of the samples were evaluated using X-ray diffraction, field-emission scanning electron microscopy, and spectrophotometry, respectively. The results show that the Ag nanoparticles are mainly positioned on the Cu₂O nanoclusters compared with the ZnO nanowire surface, forming broccoli-like Ag-Cu₂O nanoclusters during the Ar gas plasma treatment process in an aqueous solution. The diameter of the Ag/Cu₂O nanoclusters ranges from 150 to 180 nm. The Ag-Cu₂O-ZnO nanowires exhibited improved photocatalytic performance, decomposing approximately 98% methyl orange dye in 30 min. This is a consequence of the synergistic interactions between the p-n heterojunction formed at the Cu₂O-ZnO interfaces and the localized surface plasmon resonance (LSPR) effect of the Ag nanoparticles, which broaden the visible light absorption range and effectively separate the photogenerated charge carriers. Full article

The synthesis of gold(III) and gold(I)–gold(III) complexes with phosphide bridges is still a matter that requires solutions for their marked instability, in spite of the affinity of this metal in both oxidation states for phosphorous donor ligands. In the course of our studies, we realized that the presence of perhalophenyl groups of the type pentafluorophenyl or 3,5-dichlorotrifluorophenyl in the complexes gives rise to an increase in their stability that eases their isolation and structural characterization. In this paper, we describe two new fully characterized neutral compounds of this type to extend the knowledge on this family of compounds, [{Au(C₆Cl₂F₃)₂}₂(µ-PPh₂)₂] (1) and [{Au(C₆Cl₂F₃)₂(µ-PPh₂)₂Au}₂] (2). In this work, we analyze the role of the perhalophenyl groups in the stability of these complexes by using quantum chemical topology methodologies, specifically employing an analysis of the non-covalent interactions (NCIs) in real space and evaluating the electrostatic potential surfaces (ESP). Our findings reveal the existence of appreciable π-stacking interactions among the perhalophenyl and phenyl groups in both compounds, significantly contributing to the stability of the systems. Full article

The antimicrobial application of carbon nanomaterials, such as carbon nanotubes (CNTs), capped CNTs, CNT_2–5, C₆₀, C₇₀, HO-C₆₀, [C₆₀]₂, and [C₆₀]₃ fullerenes, is increasing, owing to their low cytotoxicity properties compared to other nanomaterials such as metallic nanoparticles. Enhanced mechanical properties and antibacterial activity can be caused by the incorporation of CNTs in 3-dimensional (3D) printed nanocomposites (NCs). The interruption of the bacterial membrane resulting from the cylindrical shape and high aspect ratio properties has been found to be the most prominent antibacterial mechanism of CNTs. However, the unraveling interaction of CNTs, capped CNTs, CNT_2–5, C₆₀, C₇₀, HO-C₆₀, [C₆₀]₂, and [C₆₀]₃ fullerenes with virulence factors of the main bacterial pathogenesis has not yet been understood. Therefore, in the present study, interactions of these carbon-based nanomaterials with the eight virulence factors, including protein kinase A and (ESX)-secreted protein B of Mycobacterium tuberculosis, pseudomonas elastase and exotoxin A of Pseudomonas aeruginosa, alpha-hemolysin and penicillin-binding protein 2a of Staphylococcus aureus, and shiga toxin 2a and heat-labile enterotoxin of Escherichia coli, were evaluated with the molecular docking method of AutoDock Vina. This study disclosed that the binding affinity was highest for CNT_2–5 and [C₆₀]₃ toward alpha-hemolysin, with binding energies of −32.7 and −26.6 kcal/mol, respectively. The stability of the CNT_2–5–alpha-hemolysin complex at different times was obtained according to the normal mode analysis of ElNémo and iMOD servers. Full article

A facile and environmentally benign method for single-phase barium titanate synthesis in a water vapor medium was studied to reveal the mechanism of phase transformation of the initial simple oxide mixture and estimate the capability of the product to be used as a raw material for low-frequency dielectric ceramics. The composition and structure of the reactants’ mixture, treated in vapor at 130–150 °C as well as at 230 °C for various time periods, were investigated by means of XRD, SEM, TEM, EDX, and FTIR methods. The kinetics of the occurring phase transformation can be described using the Johnson–Mehl–Avrami–Erofeev equation. The reaction between the initial oxides was considered as a topochemical process with an apparent activation energy of 75–80 kJ mol⁻¹. A crucial role in this process belonged to the water vapor medium, which facilitated the generation of the reaction zone and the spreading inward of the solid particles. The synthesized tetragonal barium titanate powder (mean particle size of 135 nm) was sintered using a conventional technique at 1250 °C to obtain ceramics with grains of about 2 μm. Capacitance measurements identified a permittivity and dielectric loss factor of the ceramics that reached 3879 and 6.7 × 10⁻³, respectively, at 1 kHz and room temperature. Full article

Co bis(benzenedithiolate) type complexes have captivated chemists for decades for their interesting geometric and electronic structures and more recently, for their impressive ability to mediate the hydrogen evolution reaction (HER) both photo- and electrocatalytically. However, these complexes have nearly exclusively been characterized in their air-stable Co(III) oxidation states. In this work, Co(II) bis(benzenedichlorodithiolate) was prepared by chemical and electrochemical one-electron reduction. This reduced Co(II) complex was characterized by X-ray crystallography and in-depth spectroscopic studies—including UV-Vis, magnetic circular dichroism, and electron paramagnetic resonance spectroscopy. [Co(II)(Cl₂bdt)₂]²⁻ is thereby shown to be a square planar complex, with a primarily metal-centered reduction, and an S_t = 1/2 spin state. This study informs our understanding of the first step in the HER catalytic cycle of Co bis(benzenedithiolate) type complexes and paves the way for future mechanistic studies on this catalyst family. Full article

Two series of the bismuth tantalate pyrochlore samples, codoped with Mg,Mn and Zn,Mn, were synthesized via solid-phase reaction. It was established that the Bi₂Mg(Zn)_xMn_1−xTa₂O_9.5−Δ (x = 0.3; 0.5; 0.7) samples contain the main phase of cubic pyrochlore (sp. gr. Fd-3m) and an admixture of triclinic BiTaO₄ (sp. gr. P-1). In both sets, the amount of BiTaO₄ is proportional to the amount of manganese doping, however, zinc-containing samples have a higher level of impurities than magnesium-containing ones. The unit cell parameter of the Zn,Mn codoped bismuth tantalate phase increases with an increasing content of zinc ions in the samples from 10.4895(5) (x = 0.3) to 10.5325(5) Å (x = 0.7). The unit cell parameter of Mg,Mn codoped bismuth tantalate pyrochlores increases uniformly with an increasing index x(Mg) from 10.4970(8) at x = 0.3 to 10.5248(8) Å at x = 0.7, according to the Vegard rule. The NEXAFS and XPS data showed that the ions were found to have oxidation states of Bi(+3), Ta(+5), Zn(+2) and Mg(+2). In the Ta 4f XPS spectrum of both series of samples, a low energy shift of the absorption band characteristic of tantalum ions with an effective charge of (+5-δ) was observed. The XPS spectra of Bi4f7/2 and Bi4f5/2 also show a shift of bands towards lower energies which is attributed to the presence of some low-charge ions of transition elements in the bismuth position. The NEXAFS spectroscopy data showed that manganese ions in both series of samples have predominantly 2+ and 3+ oxidation states. XPS data indicate that in zinc-containing preparations the proportion of oxidized manganese ions is higher than in magnesium-containing ones. Full article

The aerobic photooxidation of sulfides into sulfoxides in eco-friendly solvents, notably water, at room temperature, represents a significant interest in the domain of synthetic chemistry. This study introduces four highly stable hexadentate Ir(III) complexes: [Ir(fpqen)](PF₆) (1), [Ir(btqen)](PF₆) (2), [Ir(bmpqen)](PF₆) (3), and [Ir(bnqen](PF₆) (4) (where bfpqen is N,N′-bis(2-(4-fluorophenyl)quinolin-8-yl)ethane-1,2-diamine, btqen is N,N′-bis(2-(4-tolyl)quinolin-8-yl)ethane-1,2-diamine, bmpqen is N,N′-bis(2-(4-methoxyphenyl)quinolin-8-yl)ethane-1,2-diamine, and bnqen is N,N′-bis(2-naphthylquinolin-8-yl)ethane-1,2-diamine). These complexes were synthesized utilizing an in situ inter-ligand C-N cross-coupling photoreaction of the precursors [Ir(L)₂(en)](PF₆) (L is 2-(4-fluorophenyl)quinoline, (2-(4-tolyl)quinoline, 2-(4-methoxyphenyl)quinoline or 2-naphthylquinoline, and en is 1,2-diamine) under benign conditions. This methodology furnishes a valuable and complementary approach for the in situ generation of multidentate complexes through a post-coordination inter-ligand-coupling strategy under mild conditions. Moreover, these hexadentate Ir(III) complexes exhibit pronounced catalytic activity and chemo-selectivity toward the aerobic photooxidations of sulfides into sulfoxides in aqueous media at room temperature, offering a new avenue for the sustainable synthesis of sulfoxides. Full article

We report a straightforward alkane elimination strategy to prepare well-defined heterobimetallic Al/Mo species. Notably, the reaction of the monohydride complex of molybdenum, Cp*MoH(CO)₃, with triisobutyl aluminum affords a new heterobimetallic [MoAl]₂ tetranuclear compound, [Cp*Mo(CO)(µ-CO)₂Al(ⁱBu)₂]₂, (1), featuring a 12-membered C₄O₄Mo₂Al₂ ring in which isocarbonyls bridge the Mo and Al centers. The addition of pyridine to this complex successfully results in the dissociation of the dimer into a new discrete binuclear complex, [Cp*Mo(CO)₂(µ-CO)Al(Py)(iBu)₂], (2). Switching the nature of the Lewis base from pyridine to tetrahydrofuran does not lead to the THF analogue of adduct 2, but rather to a complex reaction where one of the identified products corresponds to a tetranuclear species, [Cp*Mo(CO)₃(μ-CH₂CH₂CH₂CH₂O)Al(iBu)₂]₂, (3), featuring two bridging alkoxybutyl fragments originating from the C-O ring opening of THF. Compound 3 adds to the unusual occurrences of THF ring opening by heterobimetallic complexes, which is evocative of masked metal-only frustrated Lewis pair behavior and highlights the high reactivity of these Al/Mo assemblies. Full article

The dielectric properties of non-stoichiometric SrMnO₃ (SMO) thin films grown by molecular beam epitaxy were systematically investigated. Especially, the effects of cation stoichiometry-induced diverse types and densities of defects on the dielectric properties of SMO films were revealed. Two anomalous dielectric relaxation behaviors were observed at different temperatures in both Sr-rich and Mn-rich samples. High-temperature dielectric relaxation, resulting from a short-range Mn-related Jahn–Teller (JT) polaron hopping motion, was reinforced by an enhancement of JT polaron density in the Sr-rich film, which contained abundant SrO Ruddlesden–Popper (R-P) stacking faults. However, an excessive number of disordered Sr vacancy clusters in Mn-rich thin film suppressed the hopping path of JT polarons and enormously weakened this dielectric relaxation. Thus, The Sr-rich film demonstrated a higher dielectric constant and dielectric loss than the Mn-rich film. In addition, low-temperature dielectric relaxation may be attributed to the polarization/charge glass state. Full article

Two new paddlewheel-type dirhodium (Rh₂) complex isomers, formulated as trans-2,2- and 3,1-forms of [Rh₂(bhp)₄] (bhp = 6-bromo-2-hydroxypyridinate), were obtained by the reaction of 6-bromo-2-hydroxypyridine with [Rh₂(O₂CCH₃)₄(H₂O)₂] and characterized by NMR, ESI-MS, and elemental analyses. Single crystal X-ray diffraction analyses clarified that the crystal structure of trans-2,2-form takes a conventional paddlewheel-type dimer structure with no axial coordination ligands, i.e., trans-2,2-[Rh₂(bhp)₄], whereas that of the 3,1-form changed significantly depending on the kinds of solvent used for crystallization processes; dimer-of-dimers-type tetrarhodium complex, i.e., 3,1-[Rh₂(bhp)₄]₂, and a conventional paddlewheel-type dimer complex with an axial DMF ligand, i.e., 3,1-[Rh₂(bhp)₄(DMF)], were observed. The 3,1-form showed unique absorption changes that were not observed in the trans-2,2-form; the trans-2,2-form showed an absorption band at approximately 780 nm both in the solid state and in solution (CH₂Cl₂ and DMF), whereas the 3,1-form showed a similar absorption band at 783 nm in CH₂Cl₂ solution, but their corresponding bands were blue-shifted in solid state (655 nm) and in DMF solution (608 nm). The molecular structures and the origin of their unique absorption properties of these Rh₂ complexes were investigated using density functional theory (DFT) and time-dependent DFT (TDDFT). Full article

Congo red dye is classified as a toxic chemical and can be harmful if ingested, inhaled, or in contact with the skin or eyes. It can cause irritation, allergic reactions, and skin sensitization in some individuals. Thus, in this paper, CaFe₂O₄ nanoparticles were produced by a simple Pechini sol-gel approach and used as an adsorbent material for the efficient disposal of Congo red dye from aqueous solutions. The maximum adsorption capacity of the CaFe₂O₄ towards Congo red dye is 318.47 mg/g. Furthermore, the synthesized CaFe₂O₄ nanoparticles exhibit an average crystal size of 24.34 nm. Scanning electron microscopy (SEM) examination showed that the CaFe₂O₄ nanoparticles are basically ball-like particles with a mean grain size of 540.54 nm. Moreover, transmission electron microscopy (TEM) examination showed that the CaFe₂O₄ sample revealed aggregated spherical particles with a mean diameter of 27.48 nm. The Energy-dispersive X-ray spectroscopy (EDS) pattern reveals that the produced CaFe₂O₄ nanoparticles are composed of Ca, Fe, and O elements, with an atomic ratio of 1:2:4 of these elements, respectively. The disposal of Congo red dye by the synthesized CaFe₂O₄ nanoparticles is chemical, spontaneous, exothermic, perfectly aligned with the pseudo-second-order kinetic model, and exhibited excellent conformity with the Langmuir equilibrium isotherm. Full article

This review describes the progress of the gas-phase study of endometallofullerenes (EMFs) by mass spectrometry and theoretical calculation over the past 15 years. The attention herein focuses on the gas-phase syntheses, reactions, and generation mechanisms of some novel EMF ions, along with their structures and properties. The highlighted new species include EMFs with small-size carbon cages of C_2n (n < 60), multiple metal atoms (M_x@C_2n, x ≥ 3), late transition metals, and encaged ionic bonds. Furthermore, the gas-phase experimental and calculational supports for top-down or bottom-up models are summarized and discussed. These gas-phase results not only provide experimental evidence for the existence of related novel EMF species and possible synthesis methods for them, but they also provide new insights about chemical bonds in restricted space. In addition, the opportunities and further development directions faced by gas-phase EMF study are anticipated. Full article

All kingdoms of life have more than 150 different forms of RNA alterations, with tRNA accounting for around 80% of them. These chemical alterations include, among others, methylation, sulfuration, hydroxylation, and acetylation. These changes are necessary for the proper codon recognition and stability of tRNA. In Escherichia coli, sulfur modification at the wobble uridine (34) of lysine, glutamic acid, and glutamine is essential for codon and anticodon binding and prevents frameshifting during translation. Two important proteins that are involved in this thiolation modification are the L-cysteine desulfurase IscS, the initial sulfur donor, and tRNA-specific 2-thiouridylase MnmA, which adenylates and finally transfers the sulfur from IscS to the tRNA. tRNA-specific 2-thiouridylases are iron–sulfur clusters (Fe-S), either dependent or independent depending on the organism. Here, we dissect the controversy of whether the E. coli MnmA protein is an Fe-S cluster-dependent or independent protein. We show that when Fe-S clusters are bound to MnmA, tRNA thiolation is inhibited, making MnmA an Fe-S cluster-independent protein. We further show that 2-thiouridylase only binds to tRNA from its own organism. Full article

Sila[1]ferrocenophane bearing a 9-silafluorenylidene moiety (1) as a bridging unit was synthesized and isolated as a stable crystalline compound. Sila[1]ferrocenophane 1, which was newly obtained in this study, was characterized by spectroscopic analyses, a single-crystal X-ray diffraction (SC-XRD) analysis, and electrochemical measurements. Due to the characteristic 9-silafluorenyl moiety, 1 exhibited large electron affinity and a slightly higher oxidation potential relative to that of ferrocene. In addition, 1 was found to undergo ring-opening polymerization (ROP) triggered by thermolysis at a lower temperature relative to that of Ph₂Sifc (1′, fc = 1,1′-ferrocenylidene). It also underwent ROP through reduction by KC₈ to give the corresponding polymeric compound. The DFT calculations suggested that one-electron reduction of 1 would promote ring-opening polymerization, as shown in the experimental results. Full article

Ag nanowire electrodes are promising substitutes for traditional indium tin oxide (ITO) electrodes in optoelectronic applications owing to their impressive conductivity, flexibility, and transparency. This review provides an overview of recent trends in Ag nanowire electrode layer formation, including key developments, challenges, and future prospects. It addresses several challenges in integrating Ag nanowires into practical applications, such as scalability, cost-effectiveness, substrate compatibility, and environmental considerations. Additionally, drawing from current trends and emerging technologies, this review explores potential avenues for improving Ag nanowire layer-forming technologies, such as material advancements, manufacturing scalability, and adaptability to evolving electronic device architectures. This review serves as a resource for researchers, engineers, and stakeholders in nanotechnology and optoelectronics, and underscores the relationship between advancements in patterning and the application of Ag nanowire electrodes. Through an examination of key developments, challenges, and future prospects, this review contributes to the collective knowledge base and encourages continued innovation in the ever-evolving realm of Ag nanowire-based optoelectronics. Full article

The recently synthetically prepared endohedral CH₄@C₆₀ was characterized here using calculations—namely its structure, energetics, thermodynamics, and vibrational spectrum. The calculations were carried out with DFT (density-functional theory) methods, namely by the DFT M06-2X functional and MP2, as well as B2PLYPD advanced correlated, treatments with the standard 6-31++G** and 6-311++G** basis sets, corrected for the basis set superposition error evaluated using the approximative Boys–Bernardi counterpoise method. The symmetry of the endohedral obtained in the geometry optimizations was tetrahedral T. The energetics of CH₄ encapsulation into C₆₀ was attractive (i.e., with a negative encapsulation-energy term), producing a substantial energy gain of −13.94 kcal/mol at the most advanced computational level, B2PLYPD/6-311++G**. The encapsulation equilibrium constants for CH₄@C₆₀ were somewhat higher than previously found with the CO@C₆₀ system. For example at 500 K, the encapsulation equilibrium constant for CH₄@C₆₀ had a value one order of magnitude larger than for CO@C₆₀. The encapsulation thermodynamic characteristics suggest that high-pressure and high-temperature synthesis could in principle also be possible for CH₄@C₆₀. Full article

The Mn_1.2Co_0.05Fe_0.7P_0.45Si_0.5B_0.05 compound has been systematically synthesized by mechanical alloying for 15 h, followed by annealing with two heating cycles at 1373 K for 2 h and 1073 K for 24 h. The powder that was milled for 15 h revealed the main hexagonal-Mn₂P-type phase and the minor cubic-Mn₃Fe₂Si phase through X-ray diffraction examination. After annealing the same powder at 1373 K for 2 h and again at 1073 K for 24 h, the refined phase was the unique (Mn, Fe)₂(P, Si) type with a hexagonal structure. For the mechanically alloyed powder, the final crystallite size was approximately 20 nm, and it rose to 95 nm during the annealing process. Further, a large amount of lattice microstrain was achieved as a result of high-energy milling (about 0.75%). Over the whole temperature range of 373 to 923 K, the thermal analysis showed several overlapping exothermic peaks, which indicated the improvement of the microstructure after the structural relaxation and reordering process. Moreover, the Curie temperature of the alloy was retrieved at approximately 675 K. According to an analysis of the magnetic properties, the mechanically alloyed powder exhibited an exceptional soft ferromagnetic state after 15 h of milling, and the annealed alloy showed superparamagnetic characteristics. Full article