Inorganics

The review is devoted to the C–H functionalization of porphyrins. Porphyrins exhibit the properties of organic semiconductors, light energy converters, chemical and electrochemical catalysts, and photocatalysts. The review describes the iridium- and palladium-catalyzed direct functionalization of porphyrins, with more attention given to the results obtained in our laboratory. The development and improvement of synthetic methods that do not require preliminary modification of the substrate with various functional groups are extremely important for the preparation of new organic materials based on porphyrins. This makes it possible to simplify the synthetic procedure, to make the synthesis more economical, environmentally safe, and simple to perform. Full article

Organic electrode materials offer obvious opportunities to promote cost-effective and environmentally friendly rechargeable batteries. Over the last decade, tremendous progress has been made thanks to the use of molecular engineering focused on the tailoring of redox-active organic moieties. However, the electrochemical performance of organic host structures relies also on the crystal packing, like the inorganic counterparts, which calls for further efforts in terms of crystal chemistry to make a robust redox-active organic center electrochemically efficient in the solid state. Following our ongoing research aiming at elaborating lithiated organic cathode materials, we report herein on the impact of polymorphism on the electrochemical behavior of dilithium (2,3-dilithium-oxy-)terephthalate vs. Li. Having isolated dilithium (3-hydroxy-2-lithium-oxy)terephthalate through an incomplete acid-base neutralization reaction, its subsequent thermally induced decarboxylation mechanism led to the formation of a new polymorph of dilithium (2,3-dilithium-oxy-)terephthalate referred to as Li₄-o-DHT (β-phase). This new phase is able to operate at 3.1 V vs. Li⁺/Li, which corresponds to a positive potential shift of +250 mV compared to the other polymorph formerly reported. Nevertheless, the overall electrochemical process characterized by a sluggish biphasic transition is impeded by a large polarization value limiting the recovered capacity upon cycling. Full article

The aim of this research was to study the effect of temperature on the adhesion and disinfection activities of an Ag⁺-doped BiVO₄ (Ag⁺/BiVO₄) coating. Ag⁺/BiVO₄ was prepared by a sol–gel method, and spraying was used as the deposition method of coating. X-ray diffraction patterns showed that the monoclinic scheelite phase of the samples was unchanged by annealing at 450–650 °C. Scanning electron microscopy results showed that, at high temperatures, the particles melted and formed a dense coating, and the roughness of the coating decreased after initially increasing. The adhesion and disinfection activities were evaluated by ASTM D3359-08 and disinfection experiments. The results showed that the samples modified by silver had a good disinfection activity when annealed in the range of 450–650 °C. The adhesion increased upon increasing the annealing temperature. The sample annealed at 650 °C showed the best coating adhesion and completely killed Escherichia coli, Staphylococcus aureus, Shigella, and Salmonella after 2 h of visible-light irradiation. Full article

Hybrid solid-state batteries using a bilayer of ceramic and solid polymer electrolytes may offer advantages over using a single type of solid electrolyte alone. However, the impedance to Li⁺ transport across interfaces between different electrolytes can be high. It is important to determine the resistance to Li⁺ transport across these heteroionic interfaces, as well as to understand the underlying causes of these resistances; in particular, whether chemical interphase formation contributes to giving high resistances, as in the case of ceramic/liquid electrolyte interfaces. In this work, two ceramic electrolytes, Li₃PS₄ (LPS) and Li_6.5La₃Zr_1.5Ta_0.5O₁₂ (LLZTO), were interfaced with the solid polymer electrolyte PEO₁₀:LiTFSI and the interfacial resistances were determined by impedance spectroscopy. The LLZTO/polymer interfacial resistance was found to be prohibitively high but, in contrast, a low resistance was observed at the LPS/polymer interface that became negligible at a moderately elevated temperature of 50 °C. Chemical characterization of the two interfaces was carried out, using depth-profiled X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry, to determine whether the interfacial resistance was correlated with the formation of an interphase. Interestingly, no interphase was observed at the higher resistance LLZTO/polymer interface, whereas LPS was observed to react with the polymer electrolyte to form an interphase. Full article

MOF-derived carbon-based materials have attracted widespread attention due to their relatively large surface area, morphology, and their stability in water. Considering these advantages, these materials present themselves as excellent adsorbents. In this work, a novel method was designed for the fabrication of a nano zero-valent-iron (nZVI) carbon composite. The utilization of zinc oxide nanorods (ZnONRs) in the role of sacrificial consumable nuclei for the synthesis of MIL-53 sacrificial zinc oxide nanorods (MIL-53-SNR) and the subsequent pyrolysis at 700 °C in the inert atmosphere led to a graphitic-supported nZVI material (Fe-C-SNR). Fe-C-SNR was compared with a commercial zinc oxide bulk (MIL-53-SB) and with a pristine MIL-53. By virtue of the ZnONRs, Fe-C-SNR exhibited a greatly improved mesoporous structure. Consequently, the pyrolyzed materials were applied as adsorbents for methylene blue. Fe-C-SNR’s performance increased to more than double of the pyrolyzed MIL-53 (Fe-C), with a remarkably fast adsorption time (10 min) for a concentration of 10 mg L⁻¹ with only 200 mg L⁻¹ adsorbent required. This functional composite also displayed exceptional recyclability; after ten complete cycles, Fe-C-SNR was still capable of completely adsorbing the methylene blue. The utilization of ZnONRs proves itself advantageous and could further be extended to other MOFs for a wide range of applications. Full article

The catalytic effect of red mud on Vietnam anthracite’s combustion characteristics was investigated. The mineralogical composition of the red mud includes CaCO₃, Fe₂O₃, FeO(OH), FeTiO₃, and Al(OH)₃. This red mud is rich in Na, Ca, Al, Fe, and Ti. The combustion characteristics were analyzed by the thermogravimetry method. The combustion effectiveness was assessed by thermogravimetric analysis. The results were derived from a combination of several parameters, such as the ignition temperature, the burnout efficiency, and the amount of heat release. The combustion characteristics of pulverized coal were improved by the introduction of red mud, and the greatest catalytic performance was achieved when the content reached 6%. With the optimal addition, the ignition temperature of anthracite was reduced by 12 °C, and the burnout efficiencies were increased by 2.59% compared to raw anthracite. The amount of heat released by anthracite was increased to 6.93 kJ/g by adding red mud. Full article

This article presents a new approach to preparing the precursors of complex oxide systems Al₂O₃-ZrO₂-M_XO_Y (M = Mg, Ce). The approach is based on the electrogeneration and interaction of reagents with electrolyte components in a coaxial electrochemical reactor. The design of the electrolyzer provides the suspension homogenization due to the turbulence induced by the intensive hydrogen bubbles and electrolyte movement in opposite directions relative to the central electrode in a closed space. Hydrogen evolution leads to the mixing of the solution. The transfer of OH⁻ ions generated at the cathode into the electrolyte and interaction with metal ions (Zr, Al, Ce, Mg) leads to the formation of hydroxoaqua complexes of these metals. They participate in the polycondensation reaction, forming polymerized hydroxides and oxyhydroxides, which are the basis of the primary particles. The process of hydroxylation of nanoparticle surface of the formed precursors of oxide systems stabilizes the dispersion and prevents particle aggregation. The stabilized tetragonal t-ZrO₂ was obtained by sintering the precursor of the synthesized oxide system at 1100 °C with the formation of an alumina phase (γ-Al₂O₃, or an aluminum–magnesium spinel MgAl₂O₄) with a low CeO₂ content (2–3 wt%). Full article

The nature of the self-sustained reaction of reactive materials is dependent on the physical, thermal, and mechanical properties of the reacting materials. These properties behave differently at the nano scale. Low-dimensional nanomaterials have various unusual size dependent transport properties. In this review, we summarize the theoretical and experimental reports on the size effect on melting temperature, heat capacity, reaction enthalpy, and surface energy of the materials at nano scale because nanomaterials possess a significant change in large specific surface area and surface effect than the bulk materials. According to the theoretical analysis of size dependent thermodynamic properties, such as melting temperature, cohesive energy, thermal conductivity and specific heat capacity of metallic nanoparticles and ultra-thin layers varies linearly with the reciprocal of the critical dimension. The result of this scaling relation on the material properties can affect the self-sustained reaction behavior in reactive materials. Resultant, powder compacts show lower reaction propagation velocities than bilayer system, if the particle size of the reactants and the void density is decreased an increase of the reaction propagation velocity due to an enhanced heat transfer in reactive materials can be achieved. Standard theories describing the properties of reactive material systems do not include size effects. Full article

Mixed multidentate linkers with donor groups of different types can be fruitfully exploited in the self-assembly of coordination polymers (CPs) and Metal-Organic Frameworks (MOFs). In this work we develop new ligands containing a β-diketone chelating functionality, to better control the stereochemistry at the metal center, and tetrazolyl multidentate bridging groups, a combination not yet explored for networking with metal ions. The new ligands, 1,3-bis(4-(1H-tetrazol-5-yl)phenyl)-1,3-propanedione (H₃L¹) and 1-phenyl-3-(4-(1H-tetrazol-5-yl)phenyl)-1,3-propanedione (H₂L²), are synthesized from the corresponding nitrile precursors by [2+3] dipolar cycloaddition of azide under metal-free catalytic conditions. Crystal structure analysis evidences the involvement of tetrazolyl fragments in multiple hydrogen bonding giving 2D and 1D supramolecular frameworks. Reactivity of the new ligands with different metal salts indicates good coordinating ability, and we report the preparation and structural characterization of the tris–chelate complex [Fe(HL¹)₃]³⁻ (1) and the homometallic 2D CP [ZnL²(DMSO)] (2). In compound 1 only the diketonate donor is used, whereas the partially deprotonated tetrazolyl groups are involved in hydrogen bonding, giving rise to a 2D supramolecular framework of (6,3)IIa topological type. In compound 2 the ligand is completely deprotonated and uses both the diketonate donor (chelating) and the tetrazolate fragment (bridging) to coordinate the Zn(II) ions. The resulting neutral 2D network of sql topology shows luminescence in the solid state, which is red shifted with respect to the free ligand. Interestingly, it can be easily exfoliated in water to give a luminescent colloidal solution. Full article

Binary composite WS₂/TiO₂ nanofibers (WTN) were elaborated by electrospinning technique. The photocatalytic efficiency of the binary nanofibers was changed via different ratios between WS₂ and TiO₂. The structural, morphological and optical properties of the prepared nanofibers were evaluated by Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and UV-Vis diffuse reflectance spectroscopy (UV-vis/DRS), respectively. The prepared nanofibers showed a remarkable performance in photocatalytic efficiency of phenol compound degradation under visible light. WTN nanofibers showed superior photocatalytic activity (83%) and high stability of several cycles under visible light. Therefore, WS₂/TiO₂ nanofibers have great prospects for the treatment of wastewater from toxic organic contamination due to their excellent photocatalytic performance reusability and recyclability. Full article

Electrocatalysts are capable of transforming water into hydrogen, oxygen, and therefore into energy, in an environmentally friendly and sustainable manner. However, the limitations in the research of high performance catalysts act as an obstructer in the development of using water as green energy. Here, we report on a delicate method to prepare novel bimetallic metal organic framework derived electrocatalysts (C–NiCu–BDC–GO–CC) using graphene oxide (GO) modified carbon cloth as a 3D flexible and conductive substrate. The resultant electrocatalyst, C–NiCu–BDC–GO–CC, exhibited very low electron transfer resistance, which benefited from its extremely thin 3D sponge-like morphology. Furthermore, it showed excellent oxygen evolution reaction (OER) activity, achieving 10 mA/cm² at a low overpotential of 390 mV in 1 M KOH electrolyte with a remarkable durability of 10 h. Full article

Iron-sulfur (Fe/S) clusters are protein cofactors that play a crucial role in essential cellular functions. Their ability to rapidly exchange electrons with several redox active acceptors makes them an efficient system for fulfilling diverse cellular needs. They include the formation of a relay for long-range electron transfer in enzymes, the biosynthesis of small molecules required for several metabolic pathways and the sensing of cellular levels of reactive oxygen or nitrogen species to activate appropriate cellular responses. An emerging family of iron-sulfur cluster binding proteins is CIAPIN1, which is characterized by a C-terminal domain of about 100 residues. This domain contains two highly conserved cysteine-rich motifs, which are both involved in Fe/S cluster binding. The CIAPIN1 proteins have been described so far to be involved in electron transfer pathways, providing electrons required for the biosynthesis of important protein cofactors, such as Fe/S clusters and the diferric-tyrosyl radical, as well as in the regulation of cell death. Here, we have first investigated the occurrence of CIAPIN1 proteins in different organisms spanning the entire tree of life. Then, we discussed the function of this family of proteins, focusing specifically on the role that the Fe/S clusters play. Finally, we describe the nature of the Fe/S clusters bound to CIAPIN1 proteins and which are the cellular pathways inserting the Fe/S clusters in the two cysteine-rich motifs. Full article

(Hf,Zr,Ti)Co(Sb,Sn) Solid solutions were prepared by mechanical-alloying followed by hot-press method as an attempt to reduce Hf concentration and therefore the material’s cost without negatively affecting the thermoelectric performance. To this end, two different methods were applied: (a) Hf substitution with its lighter and cheaper homologue Zr; and (b) fine tuning of carrier concentration by the substitution of Sb with Sn. The isoelectronic substitution of Hf with Zr was investigated in Hf_0.6-xZr_xTi_0.4CoSb_0.8Sn_0.2 solid solutions and resulted in lower power factors and ZTs. However, the low thermal conductivity of Hf_0.4Zr_0.2Ti_0.4CoSb_0.8Sn_0.2 contributed in achieving a relatively good ZT~0.67 at 970 K. The effect of charge carrier concentration was investigated by preparing Hf_0.4Zr_0.2Ti_0.4CoSb_1-ySn_y (y = 0.15–0.25) compounds. Hf_0.4Zr_0.2Ti_0.4CoSb_0.83Sn_0.17 composition prepared by six hours milling reached the highest ZT of 0.77 at 960 K. Full article

A major problem with patient treatments using anticancer compounds is accompanying bacterial infections, which makes more information on how such compounds impact bacterial growth desirable. In the following study, we investigated the growth effects of an anticancerous non-toxic Schiff base oxidovanadium(V) complex (N-(salicylideneaminato)-N′-(2-hydroxyethyl)ethane-1,2-diamine) coordinated to the 3,5-di-tert-butylcatecholato ligand on a representative bacterium, Mycobacterium smegmatis (M. smeg). We prepared the Schiff base V-complexes as reported previously and selected a few complexes to develop a V-complex series. Biological studies of M. smeg growth inhibition were complemented by spectroscopic studies using UV-Vis spectrophotometry and NMR spectroscopy to determine which complexes were intact under biologically relevant conditions. We specifically chose to examine (1) the growth effects of Schiff base oxidovanadium complexes coordinated to a catechol, (2) the growth effects of respective free catecholates on M. smeg, and (3) to identify complexes where the metal coordination complex was more potent than the ligand alone under biological conditions. Results from these studies showed that the observed effects of Schiff base V-catecholate complex are a combination of catechol properties including toxicity, hydrophobicity, and sterics. Full article

The development of non-noble Co₃O₄ catalysts exposing highly active crystal planes to low-temperature methane oxidation is still a challenge. Hence, a facile solvothermal method was adapted to construe flower-like Co₃O₄ hierarchical microspheres (Co₃O₄-FL), which are composed of nanosheets with dominantly exposed {112} crystal planes. The flower-like hierarchical structure not only promotes the desorption of high levels of active surface oxygen and enhances reducibility, but also facilitates an increase in lattice oxygen as the active species. As a result, Co₃O₄-FL catalysts offer improved methane oxidation, with a half methane conversion temperature (T₅₀) of 380 °C (21,000 mL g⁻¹ h⁻¹), which is much lower than that of commercial Co₃O₄ catalysts (Co₃O₄-C). This study will provide guidance for non-noble metal catalyst design and preparation for methane oxidation and other oxidative reactions. Full article

This study explores the electronic properties of (C₂H₇N₄O)₂BiCl₅ using the density functional theory (DFT) method, which was compared with the experimental data. The band structure of the compound indicated that it is a direct semiconductor with a band gap energy of 3.54 eV, which was comparable with the value (3.20 eV) obtained experimentally from the UV–vis spectroscopy. The density of state study showed that the conduction band was formed mainly by Bi 6p, C 2p, and N 2p states, while the valence band was formed mainly by Cl 2p, O 2p, and N 2p states. Hirshfeld surface analysis and enrichment ratio (E) were further used to investigate and quantify the intermolecular interactions within the compound. These studies established that the most important role in the stability of the structure of this crystalline material was provided by hydrogen bonding and π–π stacking interactions. The crystalline morphology of the compound was determined using BFDH simulation, based on the single-crystal structure result. Furthermore, Fourier transform infrared spectroscopy (FTIR) was used to study the vibrational modes of carbamoyl-ganidinium cations. The charge transfer process within the anionic chains of [BiCl₅]_∝, studied using photoluminescence spectroscopy, resulted in a broad emission band with two positions of maxima centered at 336 and 358 nm. This work offers a good understanding of the optical, structural, as well as the electrical properties of (C₂H₇N₄O)₂BiCl₅, which are necessary in its applications in areas such as multifunctional magnetic, optoelectronic, and photonic systems. Full article

Vanadium is an ultratrace element present in higher plants, animals, algae, and bacteria. In recent years, vanadium complexes have been studied to be considered as a representative of a new class of nonplatinum metal anticancer drugs. Nevertheless, the study of cell signaling pathways related to vanadium compounds has scarcely been reported on and reviewed thus far; this information is highly critical for identifying novel targets that play a key role in the anticancer activity of these compounds. Here, we perform a review of the activity of vanadium compounds over cell signaling pathways on cancer cells and of the underlying mechanisms, thereby providing insight into the role of these proteins as potential new molecular targets of vanadium complexes. Full article

The incorporation of transition metals (TMs) such as Co, Fe, and Mn into SnO₂ substantially improves the reversibility of the conversion and the alloying reaction when used as a negative electrode active material in lithium-ion batteries. Moreover, it was shown that the specific benefits of different TM dopants can be combined when introducing more than one dopant into the SnO₂ lattice. Herein, a careful characterization of Co and Mn co-doped SnO₂ via transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy and X-ray diffraction including Rietveld refinement is reported. Based on this in-depth investigation of the crystal structure and the distribution of the two TM dopants within the lattice, an ex situ X-ray photoelectron spectroscopy and ex situ X-ray absorption spectroscopy were performed to better understand the de-/lithiation mechanism and the synergistic impact of the Co and Mn co-doping. The results specifically suggest that the antithetical redox behaviour of the two dopants might play a decisive role for the enhanced reversibility of the de-/lithiation reaction. Full article

The search for and design of suitable superior lithium ion conductors is a key process for developing solid state batteries. In order to realize a large range of applications, we researched the ionic conductivity of LiSiON, an example oxynitride mainly composed of elements with high abundance and a similar mixed anion size. Both its amorphous and heterovalent-doped phases were studied through density functional theory simulations. The Li⁺ ion diffusion behaviors and related properties are discussed. These elements are abundant in nature, and we found that amorphization or doping with P obviously enhanced the ionic conductivity of the system. General strategies to improve the kinetic properties of a candidate structure are presented, to help in the design of solid state electrolytes for lithium batteries. Full article