Inorganics, Volume 12, Issue 6 (June 2024) – 17 articles

Four complexes of essential metal ions, Cu(II) and Ni(II), with the new sulfonamide ligand N-(pyridin-2-ylmethyl)quinoline-8-sulfonamide (HQSMP) were synthesized and physicochemically and structurally characterized. Complex [Cu(QSMP)Cl]_n (2) consists of a polymeric chain formed by distorted square pyramidal units. In 2, the sulfonamide ligand acts as a bridge coordinating to one Cu(II) through its three N atoms and to another metal ion via one O atom in the sulfonamido group, while the pentacoordinate complex [Cu(QSMP)(C₆H₅COO)] (3) presents a highly distorted square pyramidal geometry. Complex [Ni(QSMP)(C₆H₅COO)(CH₃OH)][Ni(QSMP)(CH₃COO)(CH₃OH)] (4) consists of two mononuclear entities containing different anion coligands, either a benzoate or an acetate group. Both units exhibit a distorted octahedral geometry. The interaction of the complexes with CT-DNA was studied by means of UV-Vis and fluorescence spectroscopy, interestingly revealing that the Ni(II) complex presents the highest affinity towards the nucleic acid. Complexes 1 and 2 are able to cleave DNA. Both compounds show promising nuclease activity at relatively low concentrations by mediating the production of a reactive oxygen species (ROS). The interaction of the four complexes with bovine serum albumin (BSA) was also investigated, showing that the compounds can bind to serum proteins. The antitumor potential of complexes 1 and 2 was evaluated against the A549 lung adenocarcinoma cell line, revealing cytotoxic properties that were both dose- and time-dependent. Full article

Hybrid gold-based perovskite derivatives typically exhibit low optical bandgaps and high optical absorption coefficients, rendering them promising for photovoltaic applications. In this study, we successfully synthesized six new hybrid gold-based perovskite derivatives, namely [(C₆H₈N₂)(AuI₄)(AuI₂)](3AMPY), [(C₆H₁₄N₂)(AuI₄)(AuI₂)](3AMP), [(C₈H₁₂N)(AuI₄)](2PEAI), [(C₄H₁₄N₂O)(AuI₄)₂](OBA), [(C₆H₁₈N₂O₂)₃(AuI₄)₄(I₃)₂](DDA), and [(C₁₀H₂₆N₂O₃)(AuI₄)(I₃)](TOTA), through a straightforward and efficient hydrothermal method, achieving millimeter-sized single crystals. The structural analysis of the single crystals revealed variations in crystal structures arising from differences in constituent units and their spatial positioning relationships. First-principles calculations ascertained their high optical absorption coefficients in the visible light spectrum and indirect bandgap properties. Theoretical models indicated that the spectroscopic limited maximum efficiency (SLME) values of 3AMPY, 2PEAI, DDA, and TOTA approached approximately 30% in films of 0.5 μm thickness, signifying their potential candidacy as solar cell absorbers. Full article

Orange peel biochar (C)-supported cadmium sulfide composites (CdS-C) were prepared by the combination of hydrothermal and calcination methods. The structure and morphology were characterized in detail by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The CdS-C composite with 60% CdS exhibited the highest photocatalytic hydrogen production rate of 7.8 mmol·g⁻¹·h⁻¹, approximately 3.69 times higher than that of synthesized CdS without biochar. These results indicate that biochar derived from orange peel could be a low-cost, renewable, environmentally friendly, and metal-free co-catalyst for CdS, enhancing its photostability. Full article

Methylene blue (MB) is a well-established and extensively studied photosensitizer for photodynamic therapy (PDT), since it can generate singlet oxygen with a high quantum yield upon irradiation within the phototherapeutic (600–950 nm) window. However, its activity can decrease due to the formation of dimers or higher aggregates, which can take place in an aqueous solution at relatively high concentrations. The incorporation of this molecule into a matrix can avoid this aggregation and increase its activity relative to PDT. Silica porous nanoparticles are chosen here as a matrix to host MB. The size and pore geometry are tuned in order to decrease MB leaching while maintaining good singlet oxygen generation and colloidal stability for further applications in nanomedicine. In addition, phenyl functions are grafted on the pores of the silica matrix in order to avoid MB aggregation, thereby increasing the activity of the photosensitizer in the singlet oxygen generation. DFT calculations give insight in the structure of the aggregation of the MB units, and the roles of water and organic environments are investigated through time-dependent calculations on UV-vis spectra. Full article

Carbon dots (CDs) have emerged as significant fluorescent nanomaterials due to their bright, stable fluorescence, good biocompatibility, facile synthesis, etc. They are widely used in various scientific and practical applications, particularly in combination with mesoporous, florescent, or magnetic nanomaterials to enhance their properties. Recent research has focused on employing CDs and their composites in drug analysis, drug loading, biological imaging, disease diagnosis, and temperature sensing, with a growing interest in their biological and medical applications. In this study, we synthesized blue-fluorescent S, N-co-doped CDs (cys-CDs) using hydrothermal synthesis with L-cysteine and sodium citrate. These resulting cys-CD particles were approximately 3.8 nm in size and exhibited stable fluorescence with a quantum yield of 0.66. By leveraging the fluorescence quenching of the cys-CDs, we developed a rapid and sensitive method for baicalein detection, achieving high sensitivity in the low micromolar range with a detection limit for baicalein of 33 nM. Our investigation revealed that the fluorescence-quenching mechanism involved static quenching and inner-filter effect components. Overall, cys-CDs proved to be effective for accurate quantitative baicalein detection in real-world samples. Full article

The work presents novel composite catalytic materials—Ni and Co deposited on Magneli phase titania—and describes their complex characterization and integration into membrane electrode assemblies to produce hydrogen by electrochemical water splitting in cells with anion exchange membranes (AEMEC). Chemical composition, surface structure, and morphology were characterized by XRD and SEM analysis. The activity in the evolution of the partial electrode reactions of hydrogen (HER) and oxygen (OER) was assessed in an aqueous alkaline electrolyte (25 wt.% KOH) using linear sweep voltammetry. The interactive role of the support was investigated and discussed. Among the tested samples, the sample with 30 wt.% Co (Co30/MPT) demonstrated superior performance in the OER. The reaction started at 1.65 V, and at 1.8 V, the current density reached 75 mA cm⁻². The HER is most efficient on the sample containing 40 wt.% Ni (Ni40/MPT), where the current density reaches 95 mA at a potential of −0.5 V. The change in catalytic efficiency compared to that of the unsupported Ni and Co is due to synergism resulting from electronic interactions between the transition metal having a hyper-d-electron character and hypo-d-electron support. The pre-selected catalysts were integrated in membrane electrode assembly (MEA) using commercial and laboratory-prepared anion-conductive membranes and tested in a custom-made AEMEC. The performance was compared to that of MEA with a commercial carbon-supported Pt catalyst. It was found that the MEA with newly prepared catalysts demonstrated better performance in long-term operation (50 mA cm⁻² at 1.8 V in a 60 h durability test), which, combined with the higher cost efficiency, gave credence to considering this combination of materials as promising for AEMEC applications. Full article

Mesoporous silica nanoparticles (MSNs), an excellent carrier material, have been widely used in tumor therapy as a vector for numerous therapeutic substances to boost therapeutical efficiency and specificity, such as loading them with chemotherapy drugs to improve the efficacy of chemotherapy. Nevertheless, they still face hurdles, such as lack of specificity and poor efficacy of monotherapy. The construction of multifunctional MSNs with excellent therapeutic effects by introducing metal ions has attracted the attention of many researchers. Herein, we demonstrated a calcium doped, chemotherapy drug doxorubicin (Dox) loaded, specific degradation nanoplatform, prepared using the sol–gel method by introducing calcium ions into an MSN framework, which enabled the doped nanoplatform to enhance chemotherapy and activate anti-tumor immune response. As a proof of concept, the doping of Ca²⁺ endowed MSNs with excellent specific degradation and pH responsive drug release, and enabled the synergy of chemotherapy and calcicoptosis. Furthermore, this nanoplatform also effectively elicited immunogenic cell death (ICD) and promoted the maturation of dendritic cells (DCs), realizing the activation of the anti-tumor immune system. The Ca²⁺ doped MSNs (CMSNs), that can activate immune response with specific degradation capability, demonstrate a practical strategy for the effective synergy between chemotherapy and calcicoptosis, providing a new paradigm for promoting chemotherapy-related treatment. Full article

KNbO₃ single crystals are grown by the self-flux method using K₂CO₃ as a flux, but often suffer from discolouration. In this work, KNbO₃ single crystals were grown by the flux method using KBO₂ as a flux. KNbO₃ powder was prepared by the solid-state reaction of K₂CO₃ and Nb₂O₅. KBO₂ was fabricated by the reaction of K₂B₄O₇·4H₂O and K₂CO₃. Single crystals of KNbO₃ were grown in a Pt crucible and the structure and dielectric properties of the single crystals were investigated. X-ray diffraction showed the KNbO₃ single crystals to have an orthorhombic Cmm2 perovskite unit cell at room temperature. The existence of ferroelastic domains was revealed by transmission electron microscopy. Electron probe microanalysis showed the single crystals to be stoichiometric and contain small amounts of B. Differential thermal analysis, Raman scattering and impedance spectroscopy were used to study the phase transitions. KBO₂ may be a suitable flux for the growth of KNbO₃ single crystals. Full article

To improve the luminescent efficiency of and to design the color spectrum of phosphors, the comprehensive understanding of the correlation between physical parameters and luminescent properties is imperative, necessitating systematic experimental studies. However, unintentional variations across individually prepared samples impede the thorough investigation of the correlation. In this study, we investigate the possible sources of unintentional variation in the photoluminescence properties of phosphors during sample preparation using a solid-state reaction, explicitly focusing on the ball milling process. Based on the quantitative features of the photoluminescent properties and their associated statistical errors, we explore the impact of unintentional variation alongside intended systematic variation, highlighting its potential to obscure meaningful trends. Full article

Amorphous phase separation (APS) is ubiquitously found in a large number of glass systems, because the glass can be regarded as solid with a heterogeneous structure at the nanoscale. However, little attention has been paid to the big challenges in utilizing APS in searching novel amorphous glass from above to below, which highlights the meticulous microstructure tunability of glass. Correspondingly, we develop a novel SiO₂-Al₂O₃-P₂O₅-Li₂O-ZrO₂ glass with APS (SAPLZ APS) which has robust crystallization resistance via the APS engineering. A comparative study is conducted to reveal the APS–crystallization property relationship. It can be found that the introduced APS can substantially impede the precipitated crystal growth in the studied glass system. Considering detailed glassy structure and microstructure, a diffusion barrier around each Li-rich droplet is created by the presence of P⁵⁺ concentration surrounding the Li-rich region. Meanwhile, due to the increase in Q⁴ at the expense of Q³, the polymerization degree in the Si-rich amorphous area can be enhanced, further increasing its viscosity and raising the kinetic barrier of Si-related crystal growth. These findings provide a new manner to develop new glass with superior anti-crystallization performance. Full article

Lead contamination in water poses significant health risks, making its removal imperative. In this study, magnetic strontium ferrite (SrFe₁₂O₁₉) nanoparticles were facilely synthesized by the Pechini sol–gel method and subsequently functionalized with a novel chitosan–Schiff base ligand to obtain a novel inorganic/organic nanocomposite for removing Pb(II) ions from aqueous solutions. The chitosan–Schiff base ligand was synthesized through the reaction of chitosan with 2,4,5-trihydroxybenzaldehyde. The presence of two X-ray diffraction (XRD) peaks at 2Ɵ = 10.5° and 2Ɵ = 20.5°, alongside the characteristic SrFe₁₂O₁₉ peaks, confirmed the functionalization of the nanoparticles with the ligand. Additionally, a significant decrease in the saturation magnetization value from 40.29 emu/g in pure SrFe₁₂O₁₉ nanoparticles to 17.32 emu/g in the nanocomposite further verified the functionalization. The presence of carbon (C) and nitrogen (N) atoms in the energy-dispersive X-ray (EDX) pattern of the nanocomposite, in addition to iron (Fe), strontium (Sr), and oxygen (O), also confirmed the functionalization. The nanocomposite’s maximum adsorption capacity for Pb(II) ions was 390.63 mg/g. Moreover, the adsorption process is endothermic, spontaneous, and chemical, occurring via complexation with -C=N and -OH groups, and it fits well with the Langmuir equilibrium isotherm and the pseudo-second-order kinetic equation. Full article

We conducted a joint synthetic, spectroscopic and computational study to explore the reactivity towards cyanide (from Bu₄NCN) of a series of dinuclear complexes based on the M₂Cp₂(CO)₃ scaffold (M = Fe, Ru; Cp = η⁵-C₅H₅), namely [M₂Cp₂(CO)₂(µ-CO){µ,η¹:η²-CH=C=CMe₂}]BF₄ (1Fe-Ru), [Ru₂Cp₂(CO)₂(µ-CO){µ,η¹:η²-C(Ph)=CHPh}]BF₄ (2Ru) and [M₂Cp₂(CO)₂(µ-CO){µ-CN(Me)(R)}]CF₃SO₃ (3Fe-Ru). While the reaction of 1Fe with Bu₄NCN resulted in prevalent allenyl deprotonation, preliminary CO-NCMe substitution in 1Ru enabled cyanide addition to both the allenyl ligand (resulting in the formation of a h¹:h²-allene derivative, 5A) and the two metal centers (affording 5B1 and 5B2). The mixture of 5B1-2 was rapidly converted into 5A in heptane solution at 100 °C, with 5A being isolated with a total yield of 60%. Following carbonyl-chloride substitution in 2Ru, CN⁻ was incorporated as a terminal ligand upon Cl⁻ displacement, to give the alkenyl complex 6 (84%). The reactivity of 3Fe and 3Ru is strongly influenced by both the metal element, M, and the aminocarbyne substituent, R. Thus, 7aRu was obtained with a 74% yield from cyanide attack on the carbyne in 3aRu (R = Cy, cyclohexyl), whereas the reaction involving the diiron counterpart 3aFe yielded an unclean mixture of the metastable 7aFe and the CO/CN⁻ substitution product 8aFe. The cyano-alkylidene complexes 7aRu (R = Cy) and 7bFe (R = Me) underwent CO loss and carbene to carbyne conversion in isopropanol at 60–80 °C, giving 8aRu (48%) and 8bFe (71%), respectively. The novel compounds 5A, 5B1-2, 6 and 7aRu were characterized by IR and NMR spectroscopy, with the structure of 7aRu further elucidated by single crystal X-ray diffraction analysis. Additionally, the DFT-optimized structures of potential isomers of 5A, 5B1-2 and 6 were calculated. Full article

Lanthanide elements such as europium exhibit distinctive emissions due to the transitions of inner-shell 4f electrons. Inorganic materials containing lanthanide elements have been widely used as phosphors in conventional displays. The hybridization of lanthanide ions with organic components enables to control of the material’s shapes and properties and broadens the possibility of lanthanide compounds as inorganic–organic materials. Lanthanide ion-containing polyoxometalate anions (Ln-POM) are a promising category as an inorganic component to design and synthesize inorganic–organic hybrids. Several inorganic–organic Ln-POM systems have been reported by hybridizing with cationic surfactants as luminescent materials. However, single-crystalline ordering has not been achieved in most cases. Here, we report syntheses and structures of inorganic–organic hybrid crystals of lanthanide-based POM and bolaamphiphile surfactants with two hydrophilic heads in one molecule. An emissive decatungstoeuropate ([EuW₁₀O₃₆]⁹⁻, EuW₁₀) anion was employed as a lanthanide source. The bolaamphiphile counterparts are 1,8-octamethylenediammonium ([H₃N(CH₂)₈NH₃]²⁺, C₈N₂) and 1,10-decamethylenediammonium ([H₃N(CH₂)₁₀NH₃]²⁺, C₁₀N₂). Both hybrid crystals of C₈N₂-EuW₁₀ and C₁₀N₂-EuW₁₀ were successfully obtained as single crystals, and their crystal structures were unambiguously determined using X-ray diffraction measurements. The photoluminescence properties of C₈N₂-EuW₁₀ and C₁₀N₂-EuW₁₀ were investigated by means of steady-state and time-resolved spectroscopy. The characteristic emission derived from the EuW₁₀ anion was retained after the hybridization process. Full article

Supercapacitors are prospective energy storage devices for electronic devices due to their high power density, rapid charging and discharging, and extended cycle life. Materials with limited conductivity could have low charge-transfer ions, low rate capability, and low cycle stability, resulting in poor electrochemical performance. Enhancement of the device’s functionality can be achieved by controlling and designing the electrode materials. Graphene oxide (GO) has emerged as a promising material for the fabrication of supercapacitor devices on account of its remarkable physiochemical characteristics. The mechanical strength, surface area, and conductivity of GO are all quite excellent. These characteristics make it a promising material for use as electrodes, as they allow for the rapid storage and release of charges. To enhance the overall electrochemical performance, including conductivity, specific capacitance (C_s), cyclic stability, and capacitance retention, researchers concentrated their efforts on composite materials containing GO. Therefore, this review discusses the structural, morphological, and surface area characteristics of GO in composites with metal oxides, metal sulfides, metal chalcogenides, layered double hydroxides, metal–organic frameworks, and MXene for supercapacitor application. Furthermore, the organic and bacterial functionalization of GO is discussed. The electrochemical properties of GO and its composite structures are discussed according to the performance of three- and two-electrode systems. Finally, this review compares the performance of several composite types of GO to identify which is ideal. The development of these composite devices holds potential for use in energy storage applications. Because GO-modified materials embrace both electric double-layer capacitive and pseudocapacitive mechanisms, they often perform better than pristine by offering increased surface area, conductivity, and high rate capability. Additionally, the density functional theory (DFT) of GO-based electrode materials with geometrical structures and their characteristics for supercapacitors are addressed. Full article

FePMo₁₂O₄₀@PVP composite materials were synthesized with the regulation of polyvinylpyrrolidone (PVP) to control the structure. The samples were characterized by FT-IR, XRD, XPS, SEM, TEM and UV-Vis DRS. The composite retains the Keggin-type polyoxometalates structure, exhibiting a high specific surface area that enhances photon capture efficiency. Analysis of UV-Vis DRS absorption band edge and band gap indicated that the composite was responsive to visible light. Photocatalytic degradation of Rhodamine B (RhB) by FePMo₁₂O₄₀@PVP was investigated under commonly used LED light source, demonstrating excellent photocatalytic performance as 2.5 g-FePMo₁₂O₄₀@PVP (0.015 g) can remove 83% of RhB (10 mg/L) in 40 min. The FePMo₁₂O₄₀@PVP composite material demonstrated sustained moderate degradation efficiency even after undergoing three cycles of repeated use. The non-covalent interaction and strong interfacial coupling between PVP and FePMo₁₂O₄₀ promoted the transfer of h⁺, and e⁻, ∙O₂⁻, ·OH, and h⁺ served as the primary active species in this photocatalytic system. This environmentally friendly material has the potential to significantly reduce energy consumption and offers valuable insights for the future treatment of dye wastewater. Full article

This work studies the synthesis, characterization, and application of CuFe₂O₄ nanoparticles for the removal of acid blue 113 and malachite green dyes from aqueous media. Utilizing the combustion procedure, CuFe₂O₄ nanoparticles were synthesized using two different fuels: L-alanine (CFA) and L-valine (CFV). Besides, the synthesized CuFe₂O₄ nanoparticles were characterized through some tools, including Fourier transform infrared (FTIR), X-ray diffraction (XRD), energy-dispersive X-ray (EDX), and field emission scanning electron microscope (FE-SEM). XRD analysis verified the creation of a CuFe₂O₄ cubic spinel structure without any contaminants, revealing average crystallite sizes of 26.37 and 17.65 nm for the CFA and CFV samples, respectively. The FTIR spectra exhibited peaks indicative of metal-oxygen bond stretching, verifying the presence of a spinel formation. Elemental analysis via EDX confirmed the stoichiometric composition typical of copper ferrite. In addition, FE-SEM displayed that the CFA and CFV samples are composed of particles with spherical and irregular shapes, measuring average diameters of 188.35 and 132.78 nm, respectively. The maximum adsorption capabilities of the CFA and CFV samples towards acid blue 113 dyes are 281.69 and 297.62 mg/g, respectively. Also, the maximum adsorption capabilities of the CFA and CFV products towards malachite green dye are 280.11 and 294.99 mg/g, respectively. Kinetic and equilibrium studies revealed that the adsorption process of acid blue 113 and malachite green dyes onto the CFA and CFV samples followed the pseudo-second-order model and Langmuir isotherm. Thermodynamic analysis indicated that the adsorption process was physical, spontaneous, and exothermic. Full article

The development of advanced tin and niobium bimetallic composite electrode materials is crucial for enhancing the performance of supercapacitors. In this paper, we present a novel bimetallic composite material consisting of zero-dimensional spherical-like SnNb₂O₆ nanocomposites synthesized through the reaction of tin oxide (SnO₂) and niobium pentoxide (Nb₂O₅) precursors, alongside comparative materials. The morphology of the spherical agglomerates comprising Sn/Nb oxide particles that were nucleated on the SnNb₂O₆ surface was characterized using field emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HR-TEM). The as-prepared heterostructures of the SnNb₂O₆ composites were analyzed for elemental composition, including Sn3d, Nb3d, and O1s; moreover, chemical oxidative state analysis was performed through X-ray photoelectron spectroscopy (XPS). Additionally, cyclic voltammetry curves exhibited pseudocapacitive redox behavior for the SnNb₂O₆ composites, while the galvanostatic charge-discharge (GCD) performance demonstrated a maximum specific capacitance of 294.8 F/g at 1 A/g. Moreover, SnNb₂O₆ composite electrodes demonstrated rapid charge–discharge kinetics and excellent cycling stability, with a capacitance retention of 95.7% over 10,000 cycles. This study elucidated the synthesis of tin–niobium oxide-based composites, demonstrating their potential for high-performance supercapacitors. Full article