Compounds, Volume 5, Issue 2 (June 2025) – 15 articles

Powders with phase composition including quasi-amorphous phases and calcium carbonate CaCO₃ in the form of calcite or aragonite and sodium halite NaCl as a reaction by-product were synthesized from 0.5M aqua solutions of sodium silicate and 0.5M aqua solutions of calcium and/or magnesium chlorides. Starting solutions were taken in quantities which could provide precipitation of hydrated calcium and/or magnesium silicates with molar ratios Ca/Si = 1 (CaSi), Mg/Si = 1 (MgSi) or (Ca+Mg)/Si = 1 (CaMgSi). Hydrated calcium and/or magnesium silicates, hydrated silica, magnesium carbonate, hydrated magnesium carbonate or hydrated magnesium silicate containing carbonate ions are suspected as components of quasi-amorphous phases presented in synthesized powders. Heat treatment of synthesized powders at 400, 600, 800 °C and pressed preceramic samples at 900, 1000, 1100 and 1200 °C were used for investigation of thermal evolution of the phase composition and microstructure of powders and ceramic samples. Mass loss of powder samples under investigation during heat treatment was provided due to evacuation of H₂O (m/z = 18), CO₂ (m/z = 44) and NaCl at temperatures above its melting point. After sintering at 1100 °C, the phase composition of ceramic samples included wollastonite CaSiO₃ (CaSi_1100); enstatite MgSiO₃, clinoenstatite MgSiO₃ and forsterite Mg₂SiO₄ (MgSi_1100); and diopside CaMgSi₂O₆ (CaMgSi_1100). After sintering at 1200 °C, the phase composition of ceramics CaSi_1200 included pseudo-wollastonite CaSiO₃. After heat treatment at 1300 °C, the phase composition of MgSi_1300 powder included preferably protoenstatite MgSiO₃. The phase composition of all samples after heat treatment belongs to the oxide system CaO–MgO–SiO₂. Ceramic materials in this system are of interest for use in different areas, including refractories, construction materials and biomaterials. Powders prepared in the present investigation, both via precipitation and via heat treatment, can be used for the creation of materials with specific properties and in model experiments as lunar regolith simulants. Full article

In this study, we report the synthesis and characterization of hybrid heterostructures composed of red carbon, an organic semiconductor polymer, and the perovskite (NH₄)₃ZnCl₅. Red carbon was synthesized via the polymerization of carbon suboxide (C₃O₂), exhibiting strong light absorption and distinctive optical properties. The hybrid material was obtained by crystallizing (NH₄)₃ZnCl₅ in the presence of red carbon, leading to significant modifications in the optical characteristics of the perovskite. Comprehensive analyses, including X-ray diffraction, FTIR spectroscopy, UV-vis spectroscopy, and cyclic voltammetry, confirmed the formation of a type I heterostructure with enhanced luminescence and potential for advanced optical applications. The energy band alignment suggests that red carbon can function effectively as both a hole and electron transport medium. This work underscores the potential of (NH₄)₃ZnCl₅@red carbon hybrid heterostructures in the development of next-generation optoelectronic devices, including sensors and LEDs. Full article

This work describes the synthesis, crystal structure, and hydrophobicity tests of four bismuth(III)– and silver(I)–bromide complexes using the triammonium cations diethylenetriaminonium (H₃DETA³⁺) and N,N,N′,N″,N‴-pentamethyldiethylenetriammonium (H₃PMDTA³⁺). The prepared compounds are the 0D perovskites (H₃DETA)[BiBr₆] (1), (H₃DETA)₂[AgBr₄]Br₃ (2), and (H₃PMDTA)[BiBr₆] (3), as well as the 1D/2D mixed perovskite with minimum formula (H₃PMDTA)[Ag₃Br₆] (4), being the last three novel materials. Compounds 1 and 3 crystallize in the orthorhombic P2₁2₁2₁ space group and are discrete [BiBr₆]³⁻ units with the cation surrounding them. In both compounds, the bismuth(III) metal ion is found in a distorted octahedral coordination geometry. Compound 2 crystallizes in the monoclinic P2₁/c space group, and it is a mixed salt consisting of (H₃DETA)[AgBr₄] and (H₃DETA)Br₃, whereas the silver(I) complexes are also isolated. Finally, compound 4, which crystallizes in the orthorhombic space group Pbcn, is a combination of a 2D and 1D silver–bromide perovskite, with the cations filling the voids. The 2D structure has the minimal formula [Ag₄Br₇]³⁻, with the 1D coordination polymer [Ag₂Br₅]³⁻ being both built up by a combination of bromide ions acting as tetrahedra corner and edge-sharing bridging ligands. The silver(I) in 2 and 4 is found in a tetrahedral coordination geometry. All compounds were deposited on pristine FTO glass, resulting in an increase in the contact angle from 22° to 44°, 36°, 62°, and 54° for films of 1, 2, 3, and 4, respectively. Compounds 1 and 3 were also deposited onto Cs₂AgBiBr₆ film, and the contact angles were observed to be the same as when deposited directly onto the FTO cover glass. Full article

The characterization of volatile compounds in cheese is crucial for understanding sensory properties and consumer acceptance. Camembert cheese, a surface-ripened variety, presents a complex aroma profile shaped by biochemical and microbial interactions. Despite advances in analytical methods such as gas chromatography–mass spectrometry (GC–MS) and gas chromatography–olfactometry (GC–O), the metabolic pathways and microbial interactions defining Camembert’s aroma remain incompletely understood. This review explores the synergistic roles of microbial communities, enzymatic activity, and environmental conditions in volatile compound formation. A systematic literature review was conducted using Scopus, Web of Science, and Google Scholar to analyze the classification of volatile compounds, biochemical pathways of aroma formation, and microbial contributions. The findings highlight the essential role of Penicillium camemberti and lactic acid bacteria in aroma modulation, particularly in sulfur compounds, esters, and short-chain fatty acids. Emerging technologies such as solid-phase microextraction (SPME) and metabolomics provide new insights into volatile compound dynamics. Understanding these mechanisms may enhance aroma control in cheese production through microbial engineering and biochemical monitoring. This review underscores the need for integrated approaches to optimize fermentation and ensure sensory standardization, contributing to improved quality and consumer acceptance of Camembert cheese. Full article

One of the most pressing issues confronting modern society is carbon dioxide pollution (CO₂). The reliance of social progress on CO₂-producing technologies such as power generation, automobiles, and specialized industrial processes exacerbates the problem. Due to this reliance, it is critical to develop solutions to reduce CO₂ emissions from these sources. One such solution is carbon capture and sequestration (CCS), which employs chemical methods to prevent CO₂ emissions. The irreversibility of current CCS technology is its primary problem. Chitin, chitosan, and their derivatives, which were recovered from local seafood waste, are studied as reversible CO₂ capture materials in this study in an effort to lessen this issue. Polysulfone (PSF) blends were employed to lessen chitosan edema, as chitosan’s hydrophilicity reduces its active sorption surface. Blends with only 20% chitosan have the same high sorption capacity as pure chitosan due to decreased swelling. Hydrolysis was used to boost the chitin sorption abilities. The CO₂ sorption data were analyzed using an Intelligent Gravimetric Analyzer (IGA), Fourier-Transform Infrared (FTIR) spectroscopy, and Matrix-Assisted Laser Desorption/Ionization-Time of Flight (MALDI-TOF) spectroscopy. This study reveals that shrimp shells were the best source of chitin. This research led to the creation of eco-friendly, reversible, and reusable carbon sequestration sorbents. Full article

Laccases are versatile enzymes capable of oxidizing a wide variety of antibiotics. In this study, the mechanism of catalytic oxidation of first-generation tetracyclines, namely, oxytetracycline, tetracycline, and chlortetracycline, by the Melanocarpus albomyces laccase enzyme was investigated using molecular docking and DFT calculations. Molecular docking studies revealed that all three substrates exhibit negative interaction energies, indicating stable enzyme–substrate complexes, with tetracycline and chlortetracycline showing the highest binding affinities. Global reactivity indices obtained by DFT confirmed the high electrophilicity of the enzyme active site, particularly the aminoacidic residues Glu235 and His508, favoring electron transfer from the substrates. In addition, NBO analysis allowed quantification of the energy of hydrogen bonds in enzyme–substrate interactions, evidencing their key role in the stabilization of the complex. Proton transfer analysis suggested two possible mechanisms: (1) a direct concerted transfer and (2) a process mediated by water molecules. The results provide insights into the thermodynamics, electronic structure, and nature of intermolecular interactions governing the oxidation of tetracyclines by the enzyme, highlighting their potential in bioremediation strategies for antibiotic degradation. Full article

The dinuclear platinum(IV) compound {Pt(CH₃)₃}₂(μ-I)₂(μ-adenine) (abbreviated Pt₂ad), obtained by treating cubic [Pt^IV(CH₃)₃(μ₃-I)]₄ with two equivalents of adenine, was isolated and structurally characterized by single crystal X-ray diffraction. The National Cancer Institute Developmental Therapeutics Program’s in vitro sulforhodamine B assays showed Pt₂ad to be particularly cytotoxic against the central nervous system cancer cell line SF-539, and the human renal carcinoma cell line RXF-393. Furthermore, Pt₂ad displayed some degree of cytotoxicity against non-small cell lung cancer (NCI-H522), colon cancer (HCC-2998, HCT-116, HT29, and SW-620), melanoma (LOX-IMVI, Malme-3M, M14, MDA-MB-435, SK-MEL-28, and UACC-62), ovarian cancer (OVCAR-5), renal carcinoma (A498), and triple negative breast cancer (BT-549, MDA-MB-231, and MDA-MB-468) cells. Although anticancer studies involving some adenine platinum(II) compounds have been reported, this study marks the first assessment of the anticancer activity of an adenine platinum(IV) complex. Full article

The present study aims to evaluate the mechanical properties, colorimetric characteristics, and decay resistance of Pinus elliottii woods treated with oxides synthesized via green chemistry. For this purpose, an aqueous extract from Eucalyptus dunnii leaves was used to synthesize particles based on copper- and zinc-based oxides, as well as a binary oxide system (CuO/ZnO). Sodium polyacrylate was employed as a dispersant, impregnating the oxides into the wood through a horizontal autoclave using a modified Bethell process, assisted by a compressor, applying a pressure of 0.8 MPa for 30 min. The exposure to weathering aging did not significantly alter the mechanical properties of the samples, but it caused the leaching of particles from the treated wood surface, as shown by colorimetric results. Regarding the decay resistance, the copper-based oxide proved to be the most effective treatment against Trametes versicolor (a white-rot fungus), reducing mass loss down to 1.2%. The CuO/ZnO formulation reduced the mass loss caused by Gloeophyllum trabeum to 1.1%, while the zinc oxide showed minimal efficacy. Thus, oxides synthesized via green chemistry using aqueous leaf extracts and mild thermal conditions for synthesis and calcination proved effective in enhancing the wood resistance against biotic deterioration agents. Full article

Coordination compounds, characterized by the coordination of metal ions with ligands, represent a pivotal area of research in chemistry due to their diverse structures and versatile applications. This review delves into the synthesis, characterization, biological evaluation, and practical applications of these compounds. A variety of synthetic methodologies (traditional solution-based techniques) are discussed to highlight advancements in the field. Investigations into the structural, electronic, and spectral properties of coordination compounds are emphasized to provide insights into their functional attributes. The biological evaluation section focuses on their roles in antimicrobial, anticancer, and enzyme-inhibitory activities, underscoring their potential in therapeutic development. Attention is paid to nanoparticles, which are increasingly used for the treatment of oncological diseases. The metal complexes have been shown to have antibacterial, antifungal, antiviral, antioxidant, and antiproliferative properties. Additionally, the review explores their applications across domains such as catalysis, illustrating their multifaceted utility. By synthesizing recent findings and trends, this article aims to bridge the gap between fundamental chemistry and applied sciences, paving the way for innovative uses of coordination compounds in both biological and industrial contexts. Full article

The optimization of elastocaloric cooling systems based on Shape Memory Alloys (SMAs) faces significant challenges in practical implementation. Despite promising thermomechanical properties, the development of efficient and compact cooling devices is hindered by incomplete understanding of strain rate effects on transformation behavior and energy conversion efficiency. While previous research has broadly characterized general SMAs’ thermomechanical behavior, the specific relationship between strain rate and elastocaloric performance in Ni-Ti sheets requires systematic investigation to overcome these barriers. This study investigates the strain rate dependence of Ni-Ti sheets’ properties through systematic mechanical characterization across strain rates ranging from $2.56\times {10}^{-4}{\mathrm{s}}^{-1}$ to $6.15\times {10}^{-3}{\mathrm{s}}^{-1}$. Commercial Ni-Ti sheets underwent Shape Setting heat treatment and were characterized at eight different deformation levels using a universal testing machine equipped with a 50 kN load cell. Each deformation level was investigated through tests performed at four different crosshead speeds (1–24 mm/min), while monitoring stress-strain behavior and energy parameters. Results suggest distinct rate-dependent patterns in transformation stresses and energy dissipation characteristics across different strain rates. The analysis indicates that mechanical response and transformation behavior vary significantly between lower and higher strain rates, with implications for practical cooling applications. These findings aim to establish guidelines for optimizing elastocaloric performance by identifying suitable operating conditions for specific application requirements, considering factors such as energy conversion efficiency and cycling frequency. Full article

Natural polyphenols, especially the ones in their glycosylated form like hesperidin, rutin, and anthocyanins, are the most abundant phenolic compounds in citric fruits, apples, and red fruits, respectively. They stand out for their high nutraceutical potential, with various reported properties, like antioxidant, anti-inflammatory, anticarcinogenic, and cardioprotective. Nevertheless, these compounds have low bioavailability and are rapidly excreted and released by the organism. Therefore, the main goal of this work was to obtain polyphenols with increased bioactivity by functionalizing biocompounds in fruit juices, namely, orange, apple, and red fruits. This modification was achieved via hesperidinase, an enzyme that catalyzes the hydrolysis of several natural bioactive compounds. Hesperidinase was produced with Penicillium sp. The activity and stability of the produced enzyme, in its free and immobilized form, using the sol–gel method, were assessed, as well as the bioactivity of the bioprocessed juices. Moreover, after immobilizing hesperidinase in sol–gel lens-shaped particles, the activity and operational stability of the bioencapsulates were evaluated by measuring the residual activity over several runs. Using the specific substrate p-NPG, β-D-glucosidase retained 31% of its activity in the second run, 22.6% in the third, and 35% in the fourth. For α-L-rhamnosidase, using the substrate p-NPR, residual activity was 31.1% in both the fourth and fifth runs. In fruit juices, the bioencapsulates exhibited residual activities around 100% in the second run, approximately 81% in the third, and around 90% in the fourth. The antioxidant and anti-inflammatory activities of the bioprocessed juices were evaluated, and an increase in the anti-inflammatory activity was observed when compared with the non-processed juices. Full article

Herein, we present hybrid crown ether ligands with siloxane and ethylene oxide units and their coordination with the cations Li⁺, Na⁺, Mg²⁺ and Ca²⁺. The compounds prepared are (SiMe₂O)₂(C₂H₄O)₃ (1, TrEGDS = Triethylenglycoldisiloxane) and (SiMe₂O)₂(C₂H₄O)₄ (2, TeEGDS = Tetraethylenglycoldisiloxane)), as well as the metal complexes [Li(TrEGDS][GaI₄] (3), [Na(TeEGDS)][GaI₄] (4), [Mg(TrEGDS)][GaI₄]₂ (5) and [Ca(TeEGDS)][GaI₄]₂ (6). Single-crystal X-ray diffraction was used to study the prepared complexes and coordination modes in the solid state. Full article

Alumina is a well-known catalyst and catalyst support. The electrochemical properties of alumina have recently gained attention. The electrochemical response of alumina greatly depends on the type and number of surface groups present in different alumina types. The surfaces of two types of alumina, anhydrous (A) and trihydrate (T) alumina, were modified by copper through an ion-exchange procedure. The samples were characterized by diffuse reflectance UV–Vis spectroscopy. The obtained samples were used as modifiers of carbon paste electrodes. The electrochemical characterization of the samples was performed using cyclic voltammetry and two redox probes. The electrochemical behavior of samples was investigated in the alkaline and neutral media. The electroanalytical performance of the synthesized composites was tested on glutamate and hydrogen peroxide by linear sweep voltammetry. The functionalization of alumina with copper by ion exchange offered a fast and cost-effective procedure for obtaining a composite with enhanced electrochemical properties for sensing biologically important analytes. Full article

Secondary metabolites such as flavonoids bring a range of biological properties to natural products, making them potential candidates for the pharmaceutical industry. Piptadenia stipulacea (Benth.) Ducke is well known in Brazil as Jurema Branca, and yet few studies have investigated its biological and phytochemical properties. This study aimed to characterize and evaluate the biological properties of ethanolic extract obtained from the bark of Jurema Branca. Characterization was performed by qualitative phytochemistry, HPLC, and mass spectroscopy. The antibacterial properties were investigated by microdilution method, cytotoxicity by MTT method, biocompatibility testing with human erythrocytes was performed, and antioxidant properties were investigated using DPPH and ABTS radical scavenging. The phytochemical tests demonstrated that rhamnetin and luteolin were the main constituents of the extract. This is the first report of these compounds in this species. The extract presented activity against Staphylococcus aureus (MIC = 500 µg/mL) and demonstrated activity against human colorectal adenocarcinoma (HCT-116), prostate adenocarcinoma (PC-3), and acute myeloid leukemia (HL-60) cell lines with IC₅₀ of 37.96, 37.6, and 27.82 µg/mL, respectively, for this Piptadenia genus. Additionally, the extract presented excellent biocompatibility and antioxidant activity (IC₅₀ = 956.7 and 147.2 µg/mL in DPPH and ABTS methods, respectively). These results are novel for the Piptadenia genus and pave the way for further evaluations regarding the biological importance of this species. Full article

FOSs are short-chain fructose-based oligosaccharides with notable functional and health benefits. Naturally present in various fruits and vegetables, FOSs are primarily produced enzymatically or microbially from sucrose or long-chain fructans, namely, inulin. Enzymes such as fructosyltransferase, β-fructofuranosidase, and endoinulinase are typically involved in its production. The chemical structure of FOSs consists of an assembly of fructose residues combined with a glucose unit. The increasing consumer demand for healthy foods has driven the widespread use of FOSs in the functional food industry. Thus, FOSs have been incorporated into dairy products, beverages, snacks, and pet foods. Beyond food and feed applications, FOSs serve as a low-calorie sweetener for and are used in dietary supplements and pharmaceuticals. As a prebiotic, they enhance gut health by promoting the growth of beneficial bacteria, aid digestion, improve mineral absorption, and help regulate cholesterol and triglyceride levels. Generally recognized as safe (GRAS) and approved by global regulatory agencies, FOSs are a valuable ingredient for both food and health applications. This review provides an updated perspective on the natural sources and occurrence of FOSs, their structures, and physicochemical and physiological features, with some focus on and a critical assessment of their potential health benefits. Moreover, FOS production methods are concisely addressed, and forthcoming developments involving FOSs are suggested. Full article