Compounds

Following the trend of finding better thermoelectric materials among synthetic analogs of copper–chalcogenide minerals, we have synthesized iron-bearing colusites of a general formula Cu_26−xFe_xV₂Sn₆S₃₂. They crystallize in the cubic space group P-43n with the unit cell parameter increasing linearly with the iron content. At a low iron concentration, the crystal structure features disorder manifested by an anti-site effect and a shift of a part of the tin atoms from their ideal positions, which is absent for higher iron contents. The magnetization and ⁵⁷Fe/¹¹⁹Sn Mössbauer studies showed that, for x = 1, iron is present as Fe³⁺, whereas for x > 1, Fe²⁺ and Fe³⁺ coexist. Additionally, weak antiferromagnetic interactions between iron atoms and fast on the ⁵⁷Fe Mössbauer time scale (10⁷–10⁹ s⁻¹) electron transfer between adjacent Fe²⁺ and Fe³⁺ centers were revealed. Thermoelectric studies showed that iron-bearing colusites are p-type semiconductors with low thermal conductivity stemming from their complex crystal structure and structural disorder. The highest ZT of 0.78 at 700 K was found for the x = 1 iron content, where iron is present as Fe³⁺ only. Full article

We performed an enzymatic screening of synthetic peptides based on β-amyloid precursor protein substrates. The template peptide sequence was a decapeptide derived from our previous screening study, which determined several effective unnatural amino acids. In this study, new libraries containing some unnatural amino acid compounds were prepared in the solid phase and digested with the β-site amyloid precursor protein-cleaving enzyme. The reaction mixture was analyzed using high-performance liquid chromatography combined with mass spectrometry. The peptides that showed a higher cleavage than the template sequence were determined and reported. Full article

Infinitene was synthesized in a previous study in 2021, and the molecule showed high strain energy. It was not clear how the strain affected the aromatic character of the molecule. To discuss this problem, the aromatic properties of dodecacene, [12]circulene, and infinitene have been studied. The structures of these compounds have been optimized at the DFT/B3LYP/6-311G + (d,p) level of theory, and the energy of the π orbitals has been used to determine the D’ index of the aromaticity. D′ for dodecacene, [12]circulene, and infinitene were 1.45, 1.45, and 1.50, respectively, showing that infinitene is an aromatic compound but with a lower aromatic character, which is in agreement with the observed strain. Full article

Diseases caused by infections are becoming harder to treat as the antibiotics used become less effective. A combination of strategies to develop active biomaterials that enhance antibacterial effects are desirable, especially ones that cause fewer side effects and promote healing properties. The combination of nanotechnology with substances that have intrinsic antibacterial activity can result in the advance of innovative biomedical materials. In this sense, the goal of this work is to provide a summary of natural rubber latex materials obtained from the Hevea brasiliensis tree loaded with metallic and metal oxide nanoparticles. These nanoparticles have unique size-dependent chemical and physical characteristic that make them appropriate for use in pharmaceutical and medical devices, while natural rubber latex is a natural and biocompatible polymer with an intrinsic antibacterial effect. Moreover, we outline here the origin, extraction methods, and composition of natural rubber latex and different techniques for the synthesis of nanoparticles, including physical, chemical, and biological approaches. Finally, we summarize, for the first time, the state of the art in obtaining natural rubber-based materials with metallic and metallic oxide nanoparticles for biomedical applications. Full article

Coordination compounds of Co(II), Cu(II), Y(III), Zr(IV) and La(III) ions were synthesized from the N-salicylidene aniline (L) derived from the condensation of aniline with salicylaldhyde and 1,10-phenanthroline (phen) as a secondary mixed ligand. L, phen and their complexes were characterized using various physiochemical methods, such as elemental analyses (CHN), Fourier-transform infrared spectroscopy (FT-IR), molar conductance (Λ), magnetic susceptibility (μeff), proton nuclear magnetic resonance (¹H NMR), ultraviolet–visible spectroscopy (UV–Vis) and thermogravimetric analysis (TG/DTG). The analytical and spectroscopic data supporting the chemical formulas of the metal complexes and chelation of L and phen with the metal ions forming octahedral complexes. FT-IR spectra demonstrated that L chelated with metal ions as a bidentate ligand via the oxygen atom of the phenolic group with a band in the range 3378–3437 cm⁻¹ and the nitrogen atom of the azomethine group at 1612 cm⁻¹. In addition, phen chelated through two nitrogen atoms in the range 1525–1565 cm⁻¹. The ¹H NMR results confirmed the IR assumption that the ligand connected to the metal ions via the phenolic’s oxygen atom. The molar conductance measurements of the complexes revealed high values of the electrolytic nature of these complexes in the range of 90.40–125.80 S cm² mol⁻¹. Thermal analysis (TG/DTG) was used to differentiate between coordinated and hydrated water molecules and the thermal stability of the complexes. Finally, the anti-microbial activities of the complexes were investigated against fungi (Candida albicans), Gram-negative bacteria (Escherichia coli and Salmonella typhimurium) and Gram-positive bacteria (Staphylococcus aureus and Micrococcus sp.) using the disc diffusion method. The La(III) complex was significant against C. albicans compared with all other compounds and reference standard control. Full article

Organic–inorganic building blocks are an important class of hybrid materials due to the synergistic versatility of organic compounds with the robust properties of inorganic materials. Currently, the growing interest in silica hybrid materials to modify the physical and chemical properties of the silica network has led to an increasing interest in organoalkoxysilanes. A general formula of R-[Si-(OR’)₃]_n, with OR’ as a hydrolysable alkoxy group and R acting as the organic functional group (n ≥ 1), has led to precursors for many molecules. By introducing adequate organic moieties (R), organoalkoxysilanes effectively engage in surface and matrix modification of silica-based materials with smart-responsive units, coupling agents, targeting moieties, bioactive moieties etc., opening promising applications, specifically biomedical ones. Several synthetic procedures have been established to introduce the alkoxysilane moieties, including hydrosilylation, coupling reactions, and addition reactions to isocyanates. Herein, we review synthetic routes to organoalkoxysilanes and the relationship between structural features to design appropriate organoalkoxysilanes for specific applications. Full article

In spite of the widespread range of hydrogen applications as one of the greenest energy vectors, its transportation and storage still remain among the main concerns to be solved in order to definitively kickstart a rapid takeoff of a sustainable H₂ economy. The quest for a simple, efficient, and highly reversible release storage technique is a very compelling target. Many studies have been undertaken to increase H₂ storage efficiency by exploiting either chemisorption or physisorption processes, or through entrapment on different porous solid materials as sorbent systems. Among these, biomass-derived carbons represent a category of robust, efficient, and low-cost materials. One question that is still open-ended concerns the correlation of H₂ uptake with the kind and number of heteroatoms as dopant of the carbonaceous sorbent matrix, such as boron, aiming to increase whenever possible bonding interactions with H₂. Furthermore, the preferred choice is a function of the type of hydrogen use, which may involve a short- or long-term storage option. In this article, after a brief overview of the main hydrogen storage methods currently in use, all the currently available techniques for the boronation of activated carbonaceous matrices derived from recycled biomass or agricultural waste are discussed, highlighting the advantages and drawbacks of each of them. Full article

Saffron is a spice derived from the flower of Crocus sativus used as a flavoring and coloring agent in the food industry which also possesses medicinal properties. In the current study, the optimum Solid Phase Extraction (SPE) conditions for separating picrocrocin and crocins from aqueous saffron extracts were investigated, using Rotatable-Central Composite Design (RCCD) in combination with Response Surface Methodology (RSM). The optimized factors were volume of saffron extract (3 mL), elution solvent (15% v/v ACN/water for picrocrocin; and 50% v/v ACN/water for crocins), and volume of elution solvent (ACN/water) (10 mL). The response factor measured was the UV-Vis absorbance. The presence of picrocrocin and crocins in the solutions obtained from SPE was confirmed using Ultra-Performance Liquid Chromatography Quadrupole Time-of-Flight Mass Spectrometry (UPLC-QToF-MS). The above optimized SPE procedure provides economy in reagents and consumables. Full article

A multi-principal element alloy (MPEA) is a type of metallic alloy that is composed of multiple metallic elements, with each element making up a significant portion of the alloy. In this study, the initial atomic percentage of elements in an (AlFeNiTiVZr)1-xCrx MPEA alloy as a function of the position on the surface was investigated using machine learning algorithms. Given the absence of a linear relationship between the atomic percentage of elements and their location on the surface, it is not possible to discern any clear association from the dataset. To overcome this non-linear relationship, the prediction of the atomic percentage of elements was accomplished using both decision tree (DT) and random forest (RF) regression models. The models were compared, and the results were found to be consistent with the experimental findings (a coefficient of determination R² of 0.98 is obtained with the DT algorithm and 0.99 with the RF one). This research demonstrates the potential of machine learning algorithms in the analysis of wavelength-dispersive X-ray spectroscopy (WDS) datasets. Full article

Updated Abraham model correlations are reported for the transfer of organic solutes and inorganic gases to a polydimethylsiloxane coating from both water and the gas phase based on published experimental data for more than 220 different compounds. The derived mathematical expressions back-calculate the observed partitioning behavior to within standard deviations of the residuals of 0.206 and 0.176 log units, respectively. Full article

Brazilian flora are highly diverse and have great potential for research into new medicines of plant origin. Platonia insignis Mart. is a fruit tree from the Amazon region with several potential pharmacological applications already demonstrated. The present study aimed to investigate the protective effect of a mixture of the biflavones volkensiflavone and moreloflavone obtained from P. insignis flowers against the lethality induced by ethidium bromide in efflux pump overproducer strains of Staphylococcus aureus. Microdilution tests were performed to determine the minimum inhibitory concentration of ethidium bromide in the absence or presence of biflavones. The addition of biflavones to the growth medium increased the minimum inhibitory concentration of ethidium bromide against all strains tested, indicating that biflavones protected the bacterial cells against cell damage induced by this biocide agent. Comparative analysis of the infrared absorption spectra of each isolated compound, as well as of the associated compounds, demonstrated the complexation reaction, indicating that there was a preferential interaction between the H2N- groups of primary amines of ethidium bromide with the carbonyls of biflavones that formed imines -C=NH. Such complexation could reduce the amount of free ethidium bromide molecules available for DNA intercalation, resulting in the observed protective effect. These results suggest a possible technological application of the biflavones from P. insignis as protective agents against cell damage induced by ethidium bromide. Full article

The introduction of a limited number of functional groups on poly(butylene succinate) (PBS) chains by covalent bonding can impart new properties to the polymer without modifying its thermal and mechanical properties. In pursuit of a viable approach to obtain light- and heat-stabilized PBS samples, the nitroxide radical coupling (NRC) reaction between PBS macroradicals and the 3,5-di-tert-butyl-4-hydroxybenzoyl-2,2,6,6-tetramethylpiperidine-1-oxyl radical (BHB-TEMPO), a functionalizing agent bearing a sterically-hindered antioxidant phenol moiety, is here proposed. The reaction was initiated by peroxide and carried out in solution and in a melt. The functionalized materials were characterized by UV-visible spectroscopy (UV-Vis), proton nuclear magnetic resonance (¹H-NMR), and size exclusion chromatography (SEC) analysis to gain structural information and by thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC) to investigate the thermal properties. In addition, films of the samples were subjected to thermal and photo-oxidative aging to assess their resistance to degradative processes. Finally, the PBS film with the highest degree of functionalization showed the ability to protect β-carotene, a molecule found in food and drugs and that is very sensitive to UV light, from degradation. This result suggests the use of this material (either alone or blended with other biopolyesters) for biodegradable and compostable active packaging. Full article

Gout is a common rheumatic disease, resulting from hyperuricemia. Prunus mume fruit extract, after being heat-concentrated named mei extract, was empirically found to reduce the risk of gout. While neochlorogenic acid was found as the predominant phenolic compound in the fresh juice of Prunus mume, neochlorogenic acid, chlorogenic acid, and cryptogenic acid were detected as the major phenolic compounds in the mei extract. In vitro testing showed that all the three chlorogenic acid isomers exhibited comparable inhibitory activities on xanthine oxidase. The hypouricemic effects of the mei extract were evaluated in potassium oxonate-induced hyperuricemic rats. Oral administrations of the mei extract significantly reduced the plasma uric acid level in hyperuricemic rats, but did not elevate the urinary uric acid level. The results provide in vivo evidence for the anti-hyperuricemic effects of mei extract for the first time, rationalize its therapeutic usage for the treatment of hyperuricemia and gout, and propose chlorogenic acid isomers as the active ingredients. Mei extract seems to be a potential natural functional food product. Full article

Merophosphinine and phosphinine dyes were reported as phosphorus atom equivalents of merocyanine and cyanine dyes in the 1960s. Although these dyes are excellent sensitizers for enhancing photographic performance, their development has been considerably retarded because of difficulties in the synthetic process. Previously, while investigating the reactivity of fluoroalkenes with various nucleophiles, we developed fluorinated merophosphinine and phosphinine scaffolds in a single reaction step; however, we did not investigate their ultraviolet-visible (UV-vis) light absorption properties further. Therefore, in this study, we synthesized fluorinated merophosphinines and phosphinine derivatives using triphenylphosphonium ylides with various R substituents [R = H, C₆H₅, 4-MeOC₆H₄, 4-PhC₆H₄, or C₆F₅] and octafluorocyclopentene to study their absorption characteristics. Thermogravimetric analyses (TGA) indicated that several synthesized derivatives were thermally stable at temperatures above 241 °C. Additionally, when studied in various solvents, the fluorinated merophosphinine and phosphinine dyes exhibited well-defined maximum absorption wavelengths (λ_abs) in the 364–375 and 420–474 nm ranges, respectively. Thus, fluorinated merophosphinine and phosphinine derivatives may serve as promising thermally stable functional dyes for future technical applications. Full article

Myoporum sandwicense A. Gray (naio) is one of the characteristic trees of Hawaiian montane–subalpine mesic forests. In this study, lab-distilled oils of M. sandwicense leaves, wood, and twigs growing on the island of Hawaii, as well as industrially produced wood oils, were characterized by gas chromatography–mass spectrometry (GC-MS). The lab-distilled oils were screened for antimicrobial activity. M. sandwicense leaf essential oil was rich in β-caryophyllene (15.1%), α-humulene (12.8%), germacrene D (7.9%), bicyclogermacrene (12.5%), brigalow ketol (9.6%), and myoporone (16.8%), while the wood essential oils were dominated by α-bisabolol and trans-α-bisabolol oxide B. The sapwood oil was dominated by palmitic acid (35.5%), linoleic acid (19.7%), oleic acid (31.9%), and stearic acid (5.7%), whereas the oil from twigs was rich in tricosane (77.3%) and pentacosane (13.1%). M. sandwicense essential oils were screened for antimicrobial activity against a panel of potentially pathogenic bacteria and fungi. The leaf essential oil of M. sandwicense showed excellent antibacterial activity against S. pyogenes and antifungal activity against A. fumigatus. The wood essential oil showed notable activity against S. pyogenes, A. fumigatus, A. niger, and M. gypseum. The twig oil was remarkably active against mold species. This work is the first report we are aware of on the composition and antimicrobial properties of naio essential oils. Full article

Beauty and personal care became a significant part of the global economy for two reasons: (1) The elderly growing in the global population and (2) the desire of women and men to appear younger and more attractive. Thus, both young and old people are looking for revolutionary nutritional eco-cosmetics (combined use of cosmeceuticals and nutraceuticals) manufactured by natural active ingredients, using biopolymers as substrates, and made by innovative and sustainable technologies. Consequently, the market of both cosmetics and diet supplements is continually growing together with the request of natural active ingredients, including bio-peptides and biological macromolecules such as chitin and lignin. Therefore, both consumers and industry need to recover innovative active ingredients and carriers (vehicles), naturally derived and supported by advanced methods for controlling their effectiveness and safeness on skin and mucous membrane layers. The use of selected bio-ingredients, such as hyaluronic acid and bio-mimetic peptides, obtained by advanced, innovative and sustainable bio nanotechnologies, will be of interest to develop smart cosmeceutical and nutraceutical formulations. Innovation is considered the key business strategy to drive sustainable economic growth. For trying to reduce waste and produce sustainable, biodegradable and innovative products, the realization of new non-woven tissues, used as carriers for making innovative cosmeceuticals and nutraceuticals was considered. Both carriers and active ingredients have been obtained from food waste to reduce loss and pollution. This review will report a brief description of the skin functions, trying also to focus and discuss some of the active ingredients and carriers used in nutritional eco-cosmetics to clarify the supposed mechanism of action, effectiveness and safeness of both active ingredients and carriers, as well as the supposed activity of beauty and personal care products. Full article

During the last three decades, secondary metabolites of marine origin have emerged as a significant source of bioactive compounds. Among the marine organisms explored, sponges offer a vast number of metabolites with unique structural diversity and a plethora of biological activities. Ageladine A, a fluorescent bromopyrrole alkaloid isolated from the marine sponge Agelas nakamurai, exhibited matrix metalloproteinase (MMP) inhibitory properties, as well as antiangiogenic activity. Due to this interesting biological profile, Ageladine A became, soon after its discovery, a target for total synthesis. In addition, a significant number of derivatives have been synthesized, and their biological activity was evaluated. The present review highlights all the successful efforts made towards the synthesis of Ageladine A. Furthermore, all the medicinal chemistry approaches to identify and assess new more potent inhibitors and to elucidate the structural features responsible for the activity are described. Full article

The discovery of azomycin provided the major impulse for the systematic search for medicines showing activity against anaerobic protozoa. Nowadays, many other interesting applications have been found for nitroimidazoles as therapeutic agents. This research led to the acquisition of numerous new 4-amine-5-nitroimidazole derivatives, which have a structure analogous to metronidazole, characteristic of medicines most widely used in the treatment of anaerobic bacteria, protozoa and parasitic infections. The therapeutic activity of the described compounds is analyzed and confirmed with predictive methods. Full article