Inorganics, Volume 11, Issue 12 (December 2023) – 37 articles

In the present work, a hybrid organic–inorganic semiconductor (HOIS) has been used to modify the surface of a graphite paste/silica (G–SiO₂) film electrode on a conducting glass substrate to fabricate a promising, sensitive voltammetric sensor for the vasoconstrictor bisartan BV6, which could possibly treat hypertension and COVID-19. The HOIS exhibits exceptional optoelectronic properties with promising applications not only in light-emitting diodes, lasers, or photovoltaics but also for the development of voltammetric sensors due to the ability of the immobilized HOIS lattice to interact with ions. This study involves the synthesis and characterization of an HOIS and its attachment on the surface of a G–SiO₂ film electrode in order to develop a nanocomposite, simple, sensitive with a fast-response, low-cost voltammetric sensor for BV6. The modified HOIS electrode was characterized using X-ray diffraction, scanning electron microscopy, and optical and photoluminescence spectroscopy, and its electrochemical behavior was examined using cyclic voltammetry. Under optimal conditions, the modified G–SiO₂ film electrode exhibited a higher electrocatalytic activity towards the oxidation of BV6 compared to a bare graphite paste electrode. The results showed that the peak current was proportional to BV6 concentration with a linear response range from 0 to 65 × 10⁻⁶ (coefficient of determination, 0.9767) and with a low detection limit of 1.5 × 10⁻⁶ M (S/N = 3), estimated based on the area under a voltammogram, while it was 3.5 × 10⁻⁶ for peak-based analysis. The sensor demonstrated good stability and reproducibility and was found to be appropriate for the determination of drug compounds such as BV6. Full article

There is no doubt that organic dyes currently play an indispensable role in our daily life; they are used in products such as furniture, textiles, and leather accessories. However, the main problems related to the widespread use of these dyes are their toxicity and non-biodegradable nature, which mainly are responsible for various environmental risks and threaten human life. Therefore, the elimination of these toxic materials from aqueous media is highly recommended to save freshwater resources, as well as our health and environment. Heterogeneous photocatalysis is a potential technique for dye degradation, in which a photocatalyst is used to absorb light (UV or visible) and produce electron–hole pairs that enable the reaction participants to undergo chemical changes. In the past, various metal oxides have been successfully applied as promising photocatalysts for the degradation of dyes and various organic pollutants due to their wide bandgap, optical, and electronic properties, in addition to their low cost, high abundance, and chemical stability in aqueous solutions. Various parameters play critical roles in the total performance of the photocatalyst during the photocatalytic degradation of dyes, including morphology, which is a critical factor in the overall degradation process. In our article, the recent progress on the morphological dependence of photocatalysts will be reviewed. Full article

In recent times, the global landscape of disease detection and monitoring has been profoundly influenced by the convergence of nanotechnology and biosensing techniques. Biosensors have enormous potential to monitor human health, with flexible or wearable variants, through monitoring of biomarkers in clinical and biological behaviors and applications related to health and disease, with increasing biorecognition, sensitivity, selectivity, and accuracy. The emergence of nanomaterial-based biosensors has ushered in a new era of rapid and sensitive diagnostic tools, offering unparalleled capabilities in the realm of disease identification. Even after the declaration of the end of the COVID-19 pandemic, the demand for efficient and accessible diagnostic methodologies has grown exponentially. In response, the integration of nanomaterial biosensors into breathalyzer devices has gained considerable attention as a promising avenue for low-cost, non-invasive, and early detection of COVID-19. This review delves into the forefront of scientific advancements, exploring the potential of emerging nanomaterial biosensors within breathalyzers to revolutionize the landscape of COVID-19 detection, providing a comprehensive overview of their principles, applications, and implications. Full article

In this work, we developed two new polyfunctional hybrid systems in which the presence of Fc redox “antennas” on peptide scaffolds allows for a modulation of their electronic properties. Specifically, we synthesized two helical hexapeptides containing four Aib (α-amionoisobutyric acid) and two _L-Dap (2,3-diamino propionic acid) residues. _L-Dap side chains were then functionalized with Fc moieties. The structures of the two 3₁₀ helical peptides, namely Z-Aib-_L-Dap(Fc)-Aib-Aib-_L-Dap(Fc)-Aib-NH-iPr and Z-Aib-_L-Dap(Fc)-Aib-_L-Dap(Fc)-Aib-Aib-NH-iPr, were investigated by X-ray diffraction, 2D-NMR, CD and IR spectroscopies. Due to the helical conformation, in Z-Aib-_L-Dap(Fc)-Aib-Aib-_L-Dap(Fc)-Aib-NH-iPr, the Fc groups are located on the same face of the helix, but in Z-Aib-_L-Dap(Fc)-Aib-_L-Dap(Fc)-Aib-Aib-NH-iPr, they are located on opposite faces. Surprisingly, two bands were found through DPV for Z-Aib-_L-Dap(Fc)-Aib-_L-Dap(Fc)-Aib-Aib-NH-iPr, indicating an electrostatic interaction between the Fc groups despite their longer reciprocal distance with respect to that in Z-Aib-_L-Dap(Fc)-Aib-Aib-_L-Dap(Fc)-Aib-NH-iPr. CD experiments at different concentrations evidenced aggregation for Z-Aib-_L-Dap(Fc)-Aib-_L-Dap(Fc)-Aib-Aib-NH-iPr, even at high dilutions, thus suggesting that the Fc-Fc electrostatic interaction could be of an intermolecular nature. Full article

Vanadium (IV) chalcogenide materials are of increasing interest for use in catalysis and energy conversion-related applications. Since no ternary compounds are yet known in the V–Se–Te system, we studied ternary V_wSe_yTe_2−y (w = 1.10, 1.13; y = 0.42, 0.72) phases crystallizing in space group P$\overline{3}$m1 (no. 164). Two single-crystal specimens with differing compositions of a solid solution were obtained using the ceramic method. All products were characterized by either single-crystal or powder X-ray diffraction. The lattice parameters increase with rising tellurium content in accordance with the larger ionic radius of the tellurium anion compared to selenium. The chemical compositions were confirmed by energy-dispersive X-ray spectroscopy. Furthermore, magnetic measurements mostly revealed antiferromagnetic properties. Simultaneous differential scanning calorimetry/thermogravimetric analyses in a nitrogen atmosphere showed endothermic decomposition accompanied by the formation of VN. The decomposition of VSe and VTe was observed in an argon atmosphere. The results of this work can serve as a basis for the synthesis of new phases in the V–Se–Te and related vanadium chalcogenide systems. Full article

We explore the use of industrial sources of silicon and surfactant for obtaining low-cost MCM-41 materials and evaluate their performances as CO₂ adsorbents. All of them presented a high specific surface area with different structural characteristics and textural properties. Interestingly, the MCM-41 manufactured with the most economical reagents presented a S_BET of 1602 m²·g⁻¹. The template was removed by using thermal treatments in an air atmosphere or a washing process. Preservation of silanol groups proved to be more effective under washing or mild thermal treatment conditions with the advantage of their lower cost and environmental benefit. Surface reactivity against CO₂ was enhanced by anchoring APTS to silanol groups through wet grafting. All amino-functionalized materials showed a performance as CO₂ adsorbents comparable to those reported in the literature, reaching values close to 30 cm³·g⁻¹ at 25 °C and 760 mmHg. Samples with a higher concentration of silanol groups showed better performance. Our studies indicate that adsorbed CO₂ is retained at least up to 50 °C, and the CO₂ is chemisorbed on the silica modified with amine groups. The chemisorbed gas at very low pressures points to the potential use of these materials for CO₂ storage. Full article

In this paper, we report the effect of the Cr/Mn ratio on the thermodynamic properties of Ti₃₀V₆₀Mn_(10−x)Cr_x (x = 0, 3.3, 6.6 and 10) + 4 wt.% Zr alloys. It was found that the enthalpy and entropy change with the Cr/MN ratio and that the entropy and entropy variation is coupled in an enthalpy-entropy compensation fashion. Using a compensation quality factor, it was established that the enthalpy-entropy compensation is not due to a statistical origin, with a confidence of more than 95%. Full article

Transition metal inserted NbS₂ (T_xNbS₂) compounds receive great attention due to their intriguing and diverse magnetic and electric transport properties. Typically, these compounds are prepared by high-temperature synthesis from the elements, which is time and energy-consuming and yields highly crystalline products. So far, no route for preparing these compounds from precursors by thermal decomposition has been reported. Herein, we report the synthesis of a dithiocarbamate of niobium Nb₂S₄(CS₂NH₂)₄ as a precursor for the synthesis of NbS₂ by this preparative strategy. Furthermore, we demonstrate that a co-decomposition with dithiocarbamates of transition metals (here, Co and Pd) is a viable route for the synthesis of T_xNbS₂-type compounds. This is a promising route for the exploration of these compounds’ properties in the form of, e.g., nanocrystalline or thin film samples. Full article

This work presents a new ultra-high vacuum cluster tool to perform systematic studies of the early growth stages of atomic layer deposited (ALD) ultrathin films following a surface science approach. By combining operando (spectroscopic ellipsometry and quadrupole mass spectrometry) and in situ (X-ray photoelectron spectroscopy) characterization techniques, the cluster allows us to follow the evolution of substrate, film, and reaction intermediates as a function of the total number of ALD cycles, as well as perform a constant diagnosis and evaluation of the ALD process, detecting possible malfunctions that could affect the growth, reproducibility, and conclusions derived from data analysis. The homemade ALD reactor allows the use of multiple precursors and oxidants and its operation under pump and flow-type modes. To illustrate our experimental approach, we revisit the well-known thermal ALD growth of Al₂O₃ using trimethylaluminum and water. We deeply discuss the role of the metallic Ti thin film substrate at room temperature and 200 °C, highlighting the differences between the heterodeposition (<10 cycles) and the homodeposition (>10 cycles) growth regimes at both conditions. This surface science approach will benefit our understanding of the ALD process, paving the way toward more efficient and controllable manufacturing processes. Full article

Fe-S clusters are ubiquitous inorganic cofactors found in proteins across all domains of life, including viruses. Their prevalence stems from their unique redox and structural plasticity that supports functions ranging from electron transfer and catalysis to stabilization of protein structure. Although the ability of Fe-S clusters to exchange electrons is often functionally crucial, it can also act as an Achilles heel when these cofactors are exposed to oxidizing conditions, often leading to their degradation. This O₂ sensitivity has rendered certain Fe-S clusters untraceable, particularly when the nascent proteins are isolated under ambient conditions. As a consequence of this O₂ sensitivity, a growing number of proteins with roles in viral infection have been found to harbor Fe-S clusters rather than the annotated Zn²⁺ cofactor. The enigmatic protein X (HBx) of the Hepatitis B Virus is a multifunctional protein essential for viral replication and development of liver disease. Although HBx has defied biochemical characterization for over forty years, it has been shown to coordinate a redox-active Fe-S cluster that represents a significant feature for establishing its molecular function. The present review narrates the approaches to validate the HBx metallocofactor that can be broadly applied as a guide for uncovering the presence of Fe-S clusters in proteins with non-canonical sequence motifs. Full article

The prediction of stack output power in solid oxide fuel cell (SOFC) systems is a key technology that urgently needs improvement, which will promote SOFC systems towards high-power multi-stack applications. The accuracy of power prediction directly determines the control effect and working condition recognition accuracy of the SOFC system controller. In order to achieve this goal, a genetic algorithm back propagation (GA-BP) neural network is constructed to predict output power in the SOFC system. By testing 40 sets of sample data collected from the experimental platform, it is found that the GA-BP method overcomes the limitation of the traditional back propagation (BP) method—falling into local optima. Further analysis shows that the average relative error of GA-BP has decreased to 1%. The reduction of the relative error improves the accuracy of the prediction results and the average prediction accuracy. Compared with the long short-term memory (LSTM) and BP algorithm, the GA-BP prediction model significantly reduces the relative error of power output prediction, which provides a solid foundation for multi-stack SOFC systems. Full article

4-Azidopyridine (1) and SiCl₄ react with the formation of the hexacoordinate silicon complex SiCl₄(4-azidopyridine)₂ (2). Upon dissolving in warm chloroform, the complex dissociates into the constituents 1 and SiCl₄ and forms back upon cooling. Depending on the cooling, two different crystalline modifications of 2 were obtained, which feature two different trans-conformers. Slow cooling to room temperature afforded conformer 2′, which features coplanar pyridine rings. Rapid cooling to −39 °C afforded crystals of conformer 2″, in which the planes of the pyridine ligands are nearly orthogonal to one another. Whereas 2′ resembles the molecular arrangement of various other known SiX₄(pyridine)₂ (X = halide) complexes, 2″ represents the first crystallographically confirmed example of a SiX₄(pyridine)₂ complex in this conformation. Conformers 2′ and 2″ were studied with ¹³C and ²⁹Si solid state NMR spectroscopy. Their differences in ²⁹Si chemical shift anisotropy, as well as energetic differences, were further investigated with computational analyses. In spite of the similar stabilities of the two conformers as isolated molecules, the crystal packing of 2″ is less stable, and its crystallization is interpreted as a kinetically controlled effect of seed formation. (3+2)-cycloaddition of 1 and phenylacetylene in toluene at 110 °C yields a mixture of 1-(4-pyridyl)-4-phenyl-1,2,3-triazole (1,4-3) and 1-(4-pyridyl)-5-phenyl-1,2,3-triazole (1,5-3) in approximate 1:2 molar ratio. The crystal structures of the two isomers were determined via X-ray diffraction. In chloroform (at 60 °C), this reaction is slow (less than 2% conversion within 4 h), but the presence of SiCl₄ enhanced the rate of the reaction slightly, and it shifted the triazole isomer ratio to ca. 1:6 in favor of 1,5-3. Full article

This study investigates novel ferrocene-based electrochemical sensors for metal cation detection via the design, synthesis and characterisation of ferrocene derivatives. Specifically, this research determines the redox potentials of ferrocene versus decamethylferrocene to provide insight into the redox potential variations. The investigation also examines how electrochemical oxidation of the ferrocene moiety can modulate host affinity for transition metal cations via effects such as electrostatic interactions and changes to coordination chemistry. Metal ion coordination to receptors containing functional groups like imine and quinoline is explored to elucidate selectivity mechanisms. These findings advance the fundamental understanding of ferrocene electrochemistry and host–guest interactions, supporting the development of improved cation sensors with optimised recognition properties, sensitivity and selectivity. Overall, this work lays the necessary groundwork for applications in analytical chemistry and sensor technologies via customised ferrocene-derived materials. Full article

Novel hexafluoroisopropylboranes (CF₃)(CF₂H)CFBH₂·L and -borate anions [(CF₃)(CF₂H)CFBH₂X]⁻ with Lewis basic heterocyclic ligands L and the anionic substituents X = F⁻ and CN⁻ were obtained. The syntheses were accomplished by substitution reactions of the dimethyl sulfide adduct (CF₃)(CF₂H)CFBH₂·SMe₂, which was synthesized on a large scale. The hexafluoroisopropylboranes and -borates were characterized by NMR and vibrational spectroscopy, elemental analysis, and single-crystal X-ray diffraction. In addition, the thermal and electrochemical stabilities were investigated by DSC measurements and cyclic voltammetry and selected experimental data and trends are compared with theoretical ones. Full article

Nanotechnology presents promising opportunities for enhancing pest management strategies, particularly in protecting active ingredients to prolong their shelf life and effectiveness. Among different approaches, the combination of inorganic nanoparticles with active ingredients such as the main constituents of natural essential oils in one nanoarchitecture is challenging. In this study, hydrophobic calcium hydroxide nanoparticles coated with oleylamime [Ca(OH)₂@OAm NPs] were synthesized using microwave-assisted synthesis. These primary NPs were physicochemically characterized and subsequently utilized to prepare nanocapsules (NCs) either alone (Ca NCs) and/or in combination with geraniol at different ratios of Ca(OH)₂@OAm NPs and geraniol, i.e. 1:1 (CaGer1 NCs), 1:2 (CaGer2 NCs), and 1:3 (CaGer3 NCs), respectively. Among the formulations, the CaGer2 NCs demonstrated higher encapsulation efficiency (EE) and loading capacity (LC) of 95% and 20%, correspondingly. They exhibited a hydrodynamic size of 306 nm, a ζ-potential of −35 mV, and a monodisperse distribution. Release kinetics of geraniol from CaGer2 NCs indicated a pH-dependent slow release over 96 h at both 25 °C and 35 °C. In vitro antifungal assay against B. cinerea revealed a concentration-dependent activity, and the EC₅₀ values for Ca(OH)₂@OAm NPs, Ca NCs, and CaGer2 NCs were estimated to be 654 µg/mL, 395 µg/mL, and 507 µg/mL, respectively. These results underscore the potential of Ca-based nanoformulations to control plant pathogens, suggesting that while Ca NCs showcase potent antifungal attributes, the different architectures/structures play a critical role in the antifungal effectiveness of the nanoformulations that have to be explored further. Full article

The anodic reactivity of UO₂ and UO₂ doped with Gd₂O₃ was investigated by electrochemical methods in slightly alkaline conditions in the presence of silicate and calcium. At the end of the experiments, the electrodes were analysed by X-ray photoelectron spectroscopy to determine the oxidation state of the uranium on the surface. The experiments showed that the increase in gadolinia doping level led to a reduction in the reactivity of UO₂, this effect being more marked at the highest doping level studied (10 wt.% Gd₂O₃). This behaviour could be attributed to the formation of dopant-vacancy clusters (Gd^III-Ov), which could limit the accommodation of excess O²⁻ into the UO₂ lattice. In addition, the presence of Ca²⁺ and SiO₃²⁻ decreased the anodic dissolution of UO₂. In summary, the Gd₂O₃ doping in presence of silicate and calcium was found to strongly decrease the oxidative dissolution of UO₂, which is a beneficial situation regarding the long-term management of spent nuclear fuel in a repository. Full article

Three homoleptic Hg(S₂CNR₂)₂, for R = ethyl (1), isobutyl (2), and cyclohexyl (3), compounds apparently exhibit a steric-dependent supramolecular association in their crystals. The small group in 1 allows for dimer formation via covalent Hg–S interactions through an eight-membered {–HgSCS}₂ ring as the dithiocarbamato ligands bridge centrosymmetrically related Hg atoms; intradimer Hg···S interactions are noted. By contrast, centrosymmetrically related molecules in 2 are aligned to enable intermolecular Hg···S interactions, but the separations greatly exceed the van der Waals radii. The large group in 3 precludes both dimerization and intermolecular Hg···S interactions. Computational chemistry indicates that the potential region at the Hg atom is highly dependent on the coordination geometry about the Hg atom. Intramolecular (1) and intermolecular (2) spodium bonding (SpB) is demonstrated. Even at separations approaching 0.4 Å beyond the sum of the assumed van der Waals radii, the energy of the stabilization afforded by the structure directs SpB in 2 amounts to approximately 2.5 kcal/mol. A natural bond orbital (NBO) analysis points to the importance of the LP(S) → σ*(Hg–S) charge transfer and to the dominance of the dispersion forces and electron correlation to the SpB in 2. Full article

A novel heteroleptic Ag(I) compound, formulated as [AgL(PPh₃)]BF₄ (1) (where L represents 2,9-bis((E)-4-methoxystyryl)-1,10-phenanthroline and PPh₃ stands for triphenylphosphine), was successfully synthesized and thoroughly characterized. The compound’s stability in solution was confirmed through 1D and 2D nuclear magnetic resonance (NMR). The photo-irradiation of the complex in a CDCl₃ solution, utilizing a common portable UV lamp emitting at λ = 365 nm, led to the partial transformation of the E,E-geometric isomer to E,Z, ultimately yielding a 1:1.4 molar ratio of isomers. Its molecular structure was determined via X-ray crystallography, while molecular packing was assessed using Hirshfeld calculations. The most notable interactions (51%) within the cationic inner sphere involved H···H bonds. The photophysical characteristics of the complex and L were evaluated both in the solid state and in solution (dichloromethane). Compound 1 is a weak emitter, with photoluminescence quantum yields of 8.6% and 4.3% in solution and the solid state, respectively. Full article

Semicarbazones and their transition metal complexes have been investigated as biologically active compounds. This study explores the synthesis, X-ray crystallographic structure, and characterization of a novel Co(III) complex cation with a pyridoxal-isothiosemicarbazone (PLITSC) ligand, [Co(PLITSC-2H)(NH₃)₃]⁺. The structure of the complex was further elucidated by the elemental analysis and spectroscopic techniques (IR and UV–VIS). Hirshfeld surface analysis was applied for the investigation of intermolecular interactions governing crystal structure. Optimization was performed at the B3LYP/6-31 + G(d,p)(H,C,N,O,S)/LanL2DZ(Co) level of theory without any geometrical constraints. The selected level of theory’s applicability was proven after comparing experimental and theoretical bond lengths and angles. The antibacterial activity of the complex towards E. coli and B. subtilis was determined and qualified as moderate compared to Streptomycin. The formation of free radical species in the presence of the complex was further verified in the fluorescence microscopy measurements. The molecular docking towards neural nitric-oxide synthase in the brain has shown that the complex structure and relative distribution of ligands were responsible for the binding to amino acids in the active pocket. Full article

The new rubidium-containing erbium sulfide thioarsenate(III) with the structured formula RbEr₂S(S₂)[AsS₂(S₂)] was obtained from the syntheses of elemental erbium (Er), arsenic sesquisulfide (As₂S₃) and rubidium sesquisulfide (Rb₂S₃) with elemental sulfur (S) at 773 K as transparent, orange, needle-shaped crystals. RbEr₂AsS₇ crystallizes monoclinically in the space group C2/c with a = 2339.86(12) pm, b = 541.78(3) pm, c = 1686.71(9) pm and β = 93.109(3) ° for Z = 8. The crystal structure features complex [AsS₂(S₂)]³⁻ anions with two S²⁻ anions and a (S₂)²⁻ disulfide dumbbell coordinating end-on as ligands for each As³⁺ cation. Even outside the ligand sphere of As³⁺, S²⁻ and (S₂)²⁻ can be found as sulfide anions. Two distinct Er³⁺ cations are surrounded by either nine or seven sulfur atoms. The [ErS₉] polyhedra are corner- and face-connected, while the [ErS₇] units share common edges, both building chains along [010]. These different chains undergo edge connectivity with each other, resulting in the formation of corrugated layers, which are held together by Rb⁺ in chains of condensed [RbS₉] polyhedra. So, a three-dimensional network is generated, offering empty channels along [010] apt to take up the As³⁺ lone-pair cations. Wavelength-dispersive X-ray spectroscopy verified a molar Rb:Er:As:S ratio of approximately 1:2:1:7 and diffuse reflectance spectroscopy showed the typical f–f transitions of Er³⁺, while the optical band gap was found to be 2.42 eV. Full article

To mitigate the effect of CO₂ on climate change, significant efforts have been made in the past few decades to capture CO₂, which can then be further sequestered or converted into value-added compounds, such as methanol and hydrocarbons, by using thermochemical or electrocatalytic processes. However, CO₂ capture and conversion have primarily been studied independently, resulting in individual processes that are highly energy-intensive and less economically viable due to high capital and operation costs. To enhance the overall process efficiency, integrating CO₂ capture and conversion into a single system offers an opportunity for a more streamlined process that can reduce energy and capital costs. This strategy can be achieved by employing dual function materials (DFMs), which possess the unique capability to simultaneously adsorb and convert CO₂. These materials combine basic metal oxides with active metal catalytic sites that enable both sorption and conversion functions. In this review paper, we focus on the recent strategies that utilize mixed metal oxides as DFMs. Their material design and characteristics, reaction mechanisms, as well as performance and limitations will be discussed. We will also address the challenges associated with this integrated system and attempt to provide insights for future research endeavors. Full article

Two complexes, related to the active site of [FeFe]-hydrogenases, [Fe₂(CO)₄(κ²-pma)(µ-bdt)] (1) and [Fe₂(CO)₄(κ²-pma)(µ-pdt)] (2) (bdt = benzene-1,2-dithiolate, pdt = propane-1,2-dithiolate) featuring the diaza chelate ligand trans-N-(2-pyridylmethylene)aniline (pma) were prepared, in order to study the influence of such a redox ligand, potentially non-innocent, on their redox behaviours. Both complexes were synthesized by photolysis in moderate yields, and they were characterized by IR, ¹H and ¹³C{¹H} NMR spectroscopies, elemental analyses and X-ray diffraction. Their electrochemical study by cyclic voltammetry, in the presence and in the absence of protons, revealed different behaviours depending on the aliphatic or aromatic nature of the dithiolate bridge. Density functional theory (DFT) calculations showed the role of the pma ligand as an electron reservoir, allowing the rationalization of the proton reduction process of complex 1. Full article

The leaf extract of Indigofera linnaei Ali, an Indian medicinal plant, was utilized in the synthesis of copper oxide nanoparticles (CuO-NPs). Green chemistry is a safe and cost-effective method for the synthesis of nanoparticles using plant extracts. The synthesis of CuO NPs was confirmed using ultraviolet–visible (UV-visible) spectrum λ-max data with two peaks at 269 and 337 nm. Different functional groups were identified using Fourier-transform infrared spectroscopy (FT-IR). X-ray diffraction (XRD) was used to confirm the crystalline structure of the CuO-nanoparticles. Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analyses were performed to examine the surface morphology and elemental composition of the biosynthesized CuO-NPs. Furthermore, the synthesized CuO-NPs exhibited antibacterial activity against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Enterococcus faecalis. Additionally, they exhibited a good insecticidal effect on Culex quinquefasciatus larvae, with low LC₅₀ 55.716 µg/mL and LC₉₀ 123.657 µg/mL values. The CuO-NPs inhibited human breast cancer cells in a concentration-dependent manner, with an IC₅₀ value of 63.13 µg/mL. Full article

The article discusses the interaction in amino acid–gold cyanide systems using amino acids of different structures. The formation of complex compounds of gold cyanide with amino acids with the participation of carboxyl and amino groups is shown. A relationship has been established between the formation of gold complexes with amino acids and the degree of its extraction in the process of leaching from low-grade ore with sodium cyanide together with amino acids: the higher the degree of participation of the amino group in the formation of the complex, i.e., covalent bond, the more pronounced the effect of the amino acid on the degree of gold leaching. The contribution to the formation of the complex of the carboxyl group (ionic bond) and the amino group (covalent donor–acceptor) can be assessed by the intensity of the band at a wave number of 1419 cm⁻¹ of the IR spectra of the systems: gold cyanide–amino acid. This approach makes it possible to predict the effect of amino acid structure on gold recovery during cyanide leaching based on IR spectra. Full article

Ruthenium(II/III)-based compounds have gained significant interest due to the biocompatibility of ruthenium, its similarity to iron, and the possibility for structural diversification through the choice of ligands. In this contribution, two novel ligands, (2-(2-methoxyethoxy)ethyl nicotinate hydrochloride) and (2-[2-(2-methoxyethoxy)ethoxy]ethyl nicotinate hydrochloride) (pyCOO(CH₂CH₂O)_nCH₃: L2, n = 2; L3, n = 3), were synthesized and characterized via ESI-HRMS, as well as IR and NMR spectroscopies. Their structures were optimized at the B3LYP/6-311++G(d,p) level of theory, and NMR chemical shifts were predicted, along with the most important intramolecular interactions. Additionally, two neutral complexes of the general formula [RuCl₂(η⁶-p-cym) (L-κN)] (L = L2: 2; L3: 3) and two cationic complexes of the general formula [RuCl(η⁶-p-cym)(L-κN)₂][PF₆] (L = L1: 4; L2: 5) were obtained and characterized. The optimization of the structures was performed at the B3LYP/6-31+G(d,p)(H,C,N,O,Cl)/LanL2DZ(Ru) level of theory. Structural features were described, and intramolecular stabilization interactions were outlined. Full article

In this work, the combined effects of anion substitution (with Br⁻ and I⁻) and SiO₂ addition on the Li-ion conductivity in LiBH₄ have been investigated. Hexagonal solid solutions with different compositions, h-Li(BH₄)_1−α(X)_α (X = Br, I), were prepared by ball milling and fully characterized. The most conductive composition for each system was then mixed with different amounts of SiO₂ nanoparticles. If the amount of added complex hydride fully fills the original pore volume of the added silica, in both LiBH₄-LiBr/SiO₂ and LiBH₄-LiI/SiO₂ systems, the Li-ion conductivity was further increased compared to the h-Li(BH₄)_1−α(X)_α solid solutions alone. The use of LiBH₄-LiX instead of LiBH₄ in composites with SiO₂ enabled the development of an optimal conductive pathway for the Li ions, since the h-Li(BH₄)_1−α(X)_α possesses a higher conductivity than LiBH₄. In fact, the Li conductivity of the silica containing h-Li(BH₄)_1−α(X)_α is higher than the maximum reached in LiBH₄-SiO₂ alone. Therefore, a synergetic effect of combining halogenation and interface engineering is demonstrated in this work. Full article

Two-dimensional (2D) nanolayered and nanohybrid structures, which are composed of different species of organic anions and multi-valence inorganic cations, are considered favorable in the field of energy storage for use as supercapacitors. In this study, host–guest interactions were used to build a series of these nanohybrids. The host was the layered double hydroxides of vanadium–cobalt (V/Co) nanolayers with different molar ratios. Cyanate was used as a guest to design a V/Co supercapacitor with a 2D-nanolayered structure. In addition, oxalate was used as a new additive to improve the performance of the V/Co supercapacitor. X-ray diffraction, infrared spectroscopy, thermal analyses, and scanning electron microscopy confirmed the formation of the nanolayered structures of cyanate-V/Co. In the case of the oxalate-V/Co nanostructures, a new phase of cobalt oxalate was produced and combined with the nanolayered structure to build a 3D porous structure. A three-assembly electrode system was used to study the electrochemical supercapacitive behavior of the cyanate-V/Co and oxalate-V/Co nanolayered structures. The results indicated that the OXVC-20 electrode possessed the highest specific capacitance as compared to that of the OXVC-16 and CNOVC electrodes. An excellent stability performance of up to 91% after various charge–discharge cycles was detected for the optimum case. Because of the positive effect of oxalate on the supercapacitance performance of the V/Co supercapacitor, it is suggested as a new track for building active electrodes for high-performance supercapacitor applications. Full article

The reaction of UO₂ with the respective lanthanide metal and purified graphite in an arc-melting furnace led to the formation of solid solutions of the composition Ln_xU_1−xC₂, with Ln = Tb, Dy, Ho, Tm, and Lu. They all crystallize in the tetragonal CaC₂ type structure (I4/mmm, Z = 2). Elemental analyses of selected samples (EDX) confirm that the composition of the resulting solid solution is in reasonable agreement with the nominal (weighed-in) composition of the starting materials, i.e., a significant evaporation of the lanthanide metals during the arc-melting synthesis does not occur. The lattice parameters of the solid solutions were extracted using Le Bail fits of high-resolution synchrotron powder diffraction data (beamline P02.1, DESY, Hamburg, Germany; beamline BL 09, DELTA, Dortmund, Germany), revealing ideal Vegard behavior for all five solid solutions. XANES investigations on all compounds at the Ln-L_III and U-L_III edges reveal that the occupancies of the U-6d orbitals decrease with increasing x, whereas the occupancies of the Ln-5d orbitals increase, pointing to an electron transfer from the uranium to the lanthanide cations. Examination of the shifts of the absorption edge (E₀) leads to the same finding. Full article

This contribution describes the preparation, coupled with detailed characterization, of Nb₂O₅ nanofibers and their application in lithium–sulfur batteries for the improvement of electrochemical performance. The utilization of reactive needle-less electrospinning allowed us to obtain, in a single step, amorphous pre-ceramic composite PAN/Nb₂O₅ fibers, which were transformed into porous ceramic Nb₂O₅ nanofibers via calcination. Thermogravimetric studies defined that calcination at 600 °C results in crystalline ceramic fibers without carbon residues. The fibrous morphology and mean diameter (614 ± 100 nm) of the ceramic nanofibers were analyzed via scanning and transmission electron microscopy. A surface area of 7.472 m²/g was determined through nitrogen adsorption measurements, while a combination of X-ray diffraction and Raman spectroscopy was used to show the crystallinity and composition of the fibers after calcination—single T-phase Nb₂O₅. Its performance in the cathode of lithium–sulfur batteries was defined through electrochemical tests, and the obtained results were compared to a similar blank electrode. The initial discharge capacity of 0.5 C reached a value of 570 mAh∙g⁻¹, while the reversible capacity of 406 mAh∙g⁻¹ was retained after 200 cycles, representing a capacity retention of 71.3%. The presence of Nb₂O₅ nanofibers in the carbon cathode inhibits the shuttle effect through polysulphide confinement, which originates from porosity and chemical trapping. Full article