The Sierpinski triangle (ST) is a widely-known deterministic fractal structure that has attracted considerable attention recently. The fabrication of nitrogen-doped defect-free STs is appealing yet challenging. This is due to factors such as the increase in active sites, the random generation of nucleation centers, and the experimental growth conditions. In this contribution, we utilize a combination of density functional theory (DFT), Monte Carlo simulation (MC) and scanning tunneling microscopy (STM) to investigate the formation of nitrogen-doped STs. These STs are formed with nitrogen-rich, conformationally flexible 2,2' :6' ,2 ''-terpyridine-6,6 ''-dicarbonitrile (TDBT) molecules and Fe atoms on Au(111). The replacement of benzenes with three pyridine side groups facilitates the formation of the nitrogen-doped STs with a relatively high order because of the energetic preference of molecular configurations. The introduction of the rigid 4,4 ''-dicyano-1,1':3',1 ''-terphenyl (C3PC) molecules markedly induces the structural transformation of the STs from ordered to high-entropy. Moreover, the nitrogen-doped STs with an order of up to 4 can be directly visualized by low-temperature STM. (c) 2026 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.

In this work, we establish quantitative structure-property relationships (QSPR) to predict the melting temperatures of diphosphine dioxides possessing a tetradecahydrophosphanthrene core, based on four two-parameter models. Three new compounds were synthesized using the Bouveault-Blanc reduction of appropriate tertiary phosphine oxides, and these compounds exhibit high melting temperatures (approximately 280-410 °C). Models were built using a dataset of 13 compounds, including the new ones. It was found that models 1 and 2, based on molecular volume, yield satisfactory results for the entire dataset, whereas models 3 and 4, based on the calculated lattice energy from crystal structures, provide even better predictions for all compounds. The new compounds were characterized by X-ray structural analysis, differential scanning calorimetry, and theoretical calculations. Cluster analysis indicates that, for crystal stability, van der Waals forces are as important as Coulombic interactions in stabilizing the crystal lattice.

Terpene epoxides constitute a group of compounds of particular importance due to their biological activity or use in the production of polymers. It is important to develop a universal, inexpensive, and sustainable method to obtain these compounds from readily available terpenes. Chemoenzymatic epoxidation by the freeze-dried mycelium of Cladosporium cladosporioides01 is an alternative to processes based on the well-known and expensive lipase B fromCandida antarctica. In the present work, we studied the kinetics of limonene epoxidation by the fungal biocatalyst and found the highest epoxidation activity in the "green" solvent ethyl acetate with a 4-fold excess of H2O2 relative to the substrate. Epoxidation followed a two-way sequential mechanism in which the major initial product limonene 1,2-epoxide and the minor intermediate product limonene 8,9-epoxide were further converted to limonene diepoxide. Substrate specificity studies revealed that a wide number of linear and cyclic monoterpenes, e.g., linalool, citronellene, citronellal, alpha-pinene, beta-pinene, myrtenol, and perillyl alcohol, were efficiently converted to their respective epoxides by this biocatalyst. The biocatalyst may show activity in the direct oxidation of a double bond without the use of a peracid. The freeze-dried mycelium exhibited higher biocatalytic activity after defatting and high stability in ethyl acetate and in the presence of an oxidant. No decrease in its activity was observed after eight biocatalytic cycles. Therefore, the mycelium can be successfully used for the sustainable large-scale production of terpene epoxides.

A siliceous material in which a framework order was established with a surfactant with sixteen carbon atoms in alkyl chains, MCM-41-C16, was synthesised, surface-modified, and tested regarding the selected physical properties. The pristine material was extracted in an acidic aqueous alcohol and then lined with different surface groups. The properties of four adsorbents were investigated using XRD, X-ray photoelectron spectroscopy, and N2 physisorption techniques. The unit-cell constant was determined from X-ray diffractograms, being in fixed relation to the edge length of the hexagonal frame. The specific surface areas of mesopores and whole crystallites were determined from low-temperature N2-physisorption isotherms. The novelty of this work is a mathematical model of a crystalline microstructure explaining the sizes and shapes of crystalline grains in relation to adsorption features, proposed and successfully tested with the aforementioned experimental data. The roughness of the surface is different from one that is necessary to explain the experimental characteristics quantitatively.

The profitability of a green biotechnological method in obtaining limonene epoxides with the use of a new biocatalyst was calculated.

Biomimetic catalysis using porphyrins enables gentle oxidation of terpenes with molecular oxygen and light. This study explores the photooxidation of (-)-myrtenol under visible light to synthesize new terpenoid products with promising biological activity. Among the porphyrins tested, tetraphenylporphyrin (H2TPP) exhibited the highest catalytic efficiency and stability in chloroform, producing myrtenal epoxide (ME) as the main product (with a molar conversion of myrtenol of 66.2 %), confirmed by NMR and MS analyses. Other substrates, i.e. perillyl alcohol and trans-pinocarveol, did not yield redox products. The antimicrobial activity of ME was assessed against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Candida albicans using Disk Diffusion, Minimal Inhibitory Concentration, and Minimal Biofilm Eradication Concentration assays (using liquid ME) and the Quantitative Assay for Measuring the Antibiofilm Activity of Volatile Compounds (using volatile ME). Overall, ME displayed higher antimicrobial activity than myrtenol in the majority of the tests applied. The strongest effects were observed against C. albicans, followed by S. aureus, while the weakest activity was exhibited against Gram-negative bacteria. ME also showed cytotoxic effects on human colorectal cancer cells (HT-29) with significantly higher biological activity than that of (-)-myrtenol. Notably, ME at lower concentrations (5-50 µg/ml) promoted proliferation of normal cells while inhibiting the viability and proliferation of cancer cells. Porphyrin-based photooxidation is a sustainable method for converting biorenewable terpene feedstocks into new compounds that can be used in cancer treatment and antimicrobial therapy.

A series of homogeneous hybrid BPA.DA-NVP@Eu2L3 materials were obtained through an in situ approach where the luminescent dopant was formed at the molecular level with different contents (0.1; 0.2; 0.5; 1; and 2% by weight). A Europium(III) complex (Eu2L3) with quinoline-2,4-dicarboxylic acid was applied as a luminescence additive while a polymer matrix consisted of a combination of bisphenol A diacrylate (BPA.DA) and N-vinylpyrrolidone (NVP) monomers. Synthesis steps and the final materials were monitored by NMR and Fourier transform infrared spectroscopy (FTIR). The emission, excitation spectra, lifetime, and quantum yield measurements were applied for the determination of the photophysical characteristics. The thermal and mechanical properties of the obtained materials were tested via thermal analysis methods (TG/DTG/DSC and TG-FTIR) in air and nitrogen atmospheres, dynamic mechanical analysis (DMA), and hardness and bending measurements. Generally, even a small addition of the metal complex component causes changes in the thermal, mechanical, and luminescent properties. Hybrid materials with a greater europium complex content are characterized by a lower stiffness and hardness while the heterogeneity and the flexibility of the samples increase. A very small amount of an Eu2L3 admixture (0.1% wt.) in a hybrid material causes an emission in the red spectral range and the luminescence intensity was reached for the BPA-DA-NVP@1%Eu2L3 material. These materials may be potentially used in chemical sensing, security systems, and protective coatings against UV.

HRMS analysis of a set of phosphine-boranes using RP-HPLC-HRMS has been performed using an acetonitrile/water mixture. The data show that all compounds undergo ionization under the measurement conditions to afford cations of [M-H] + , [2M-H] + , [2M-3H] + , [2M-5H] + or [2M 6H] 2+ type. A detailed analysis of their structures led to the conclusion that these species might act as carbonyl-group activators.

Fungal infections cause serious problems in many aspects of human life, in particular infections in immunocompromised patients present serious problems. Current anti‐fungal antibiotics target various metabolic pathways, predominantly the cell wall or cellular membrane metabolism. Numerous compounds are available to combat fungal infections, but their efficacy is far from satisfactory and some of them display high toxicity. The emerging antibiotic resistance represents a serious issue as well. Hence, there is a considerable need for new anti‐fungal compounds with lower toxicity and higher effectiveness. One of the unique anti‐fungal antibiotics is sordarin, the only known compound that acts on the fungal translational machinery per se. Sordarin inhibits protein synthesis at the elongation step of the translational cycle, acting on eukaryotic translation elongation factor 2. In this review, we deliver a robust scientific platform promoting the development of anti‐fungal compounds, in particular focusing on the molecular action of sordarin.

Self-assembled structures formed by chemical compounds with allowed internal rotations can form various ordered phases depending on the conformation. Using classical molecular dynamics and quantum calculations for tetraphenyl derivatives with different substitutions in X and Y positions (either hydroxyl or carboxyl group), we have investigated the formation of ordered structures depending on the substitution and molecular conformation. Our paper shows that certain functional groups have a big impact on the self-assembly process. We have found that those molecules can form different phases among which the most interesting seems to be Archimedean tiling. The obtained ordered networks have been characterized by radial distribution functions, cluster analysis, and two-dimensional structure factors. (c) 2021 Elsevier B.V. All rights reserved.

Artic root is a well-known plant adaptogen with multipotential pharmacological properties. Thin-layer chromatography (TLC)-screening followed by diode-array high-performance liquid chromatography and nuclear magnetic resonance spectroscopy proved to be a reliable and convenient method for the simultaneous determination of the quality of various herbal raw materials and supplements. This combination allowed for comparing and differentiating arctic root samples as well as defining their authenticity. The study provided information on the chemical and biological properties of the seven chosen samples as well as qualitative and quantitative evaluation of the quality markers: rosavin, salidroside, and p-tyrosol. The absence of rosavin, salidroside, and p-tyrosol in three samples was detected using TLC screening and confirmed by HPLC-DAD and NMR. The paper highlighted the importance of quality control and strict regulation for herbal medicine supplements and preparations.

An efficient protocol for concurrent tandem halogen exchange/C−P cross-coupling of cycloalkenyl bromides and secondary phosphine oxides has been developed. The catalytic system is based on cheap and air-stable copper(I) iodide as the precatalyst, commercially available N,N’-dimethylethylenediamine as the ligand, and Cs2CO3 or K2CO3 as the base. The use of sodium iodide as an additive reduces the excessive use of organic bromides to near-stoichiometric by promoting the in situ transformation to the corresponding iodides. Diarylphosphine oxides undergo cycloalkenylation with 35–99 % yields and dicyclohexylphosphine oxide with 30–53 % yields. In the case of acyclic alkenyl bromides the cross-coupling products undergo conjugate addition of diphenylphosphine oxide and satisfying yields are observed only for internal olefins. In the case of aryl bromides satisfying yields (43–72 %) are observed only for sterically unhindered arenes or arenes possessing an ortho-directing group. Cycloalkenylphosphine oxides prepared in the cross-coupling reaction undergo base-catalyzed and base-promoted conjugate addition to give bis(phosphinoyl)cycloalkanes.

The lattice energy is the main factor in determining the structure even if the molecules adopt a less energetically favorable conformation.

β-Hydroxyalkylphosphine sulfides undergo [1,3]- or [1,4]-sulfur atom phosphorus-to-carbon migration in the presence of Lewis or Brønsted acids. The direction of sulfur atom migration depends on the type of acid used for the reaction. In the presence of a Brønsted acid, mainly [1,3]-rearrangement is observed, whereas a Lewis acid catalyzes the [1,4]-sulfur migration. To gain insight into the mechanism of these transformations, the stereochemistry of these rearrangements have been tested, along with the conduction of some control experiments and DFT calculations.

Stevioside is the main and the sweetest glycoside of stevia plant. It is attractive as a natural sweetener to diabetics and others on carbohydrate-controlled diets. This paper discusses the stability of stevioside under food processing conditions. It was found that stevioside was transformed not only to rubusoside, steviolbioside, steviol monoside and steviol but also to previously unknown stevioside α-anomer and rubusoside α-anomer. Those two identified stevioside transformation products are formed not only during the heating of acidic, neutral and alkaline stevioside standard solutions and stevia leaves suspensions in water and ethanol/water solvents but also during the processing of foods containing stevia. Apart from presenting the new compounds, the paper additionally shows that the recombination of sugar moiety with steviolbioside molecule in MS/ESI source can occur. The effect of molecule recombination in the MS source is known from the literature; however, it has not been reported previously in relation to stevioside derivatives.

New approaches to the synthesis of 4,7-dichloro-1,10-phenanthrolines and their corresponding 9H-carbazol-9-yl-, 10H-phenothiazin-10-yl- and pyrrolidin-1-yl derivatives were developed. Their properties have been characterized by a combination of several techniques: MS, HRMS, GC-MS, electronic absorption spectroscopy and multinuclear NMR in both solution and solid state including 15N CP/MAS NMR. The structures of 5-fluoro-2,9-dimethyl-4,7-di(pyrrolidin-1-yl)-1,10-phenanthroline (5d), 4,7-di(9H-carbazol-9-yl)-9-oxo-9,10-dihydro-1,10-phenanthroline-5-carbonitrile (6a) and 4,7-di(10H-phenothiazin-10-yl)-1,10-phenanthroline-5-carbonitrile (6b) were determined by single-crystal X-ray diffraction measurements. The nucleophilic substitutions of hydrogen followed by oxidation produced compounds 6a and 6b. The electrochemical properties of selected 1,10-phenanthrolines were investigated using cyclic voltammetry and compared with commercially available reference 1,10-phenanthrolin-5-amine (5l). The spatial distribution of frontier molecular orbitals of the selected compounds has been calculated by density functional theory (DFT). It was shown that potentials of reduction and oxidation were in consistence with the level of HOMO and LUMO energies.

Curcumin is a phenolic compound produced by some plants, among which Curcuma longa is the reachest in this principal curcuminoid. At elevated temperature curcumin degrades to trans-6-(4'-hydroxy-3'-methoxyphenyl)-2,4-dioxo-5-hexenal, vanillin, ferulic acid and feruloylmethane, however, the formation of feruloyloacetone ((5E)-6-(4-hydroxy-3-methoxyphenyl)hex-5-ene-2,4-dione) in the curcumin degradation process has not been reported yet. As results from experiments, even 28.8% or 20.6% of the degraded curcumin is transformed to feruloyloacetone during 2 h heating of alkaline or acidic curcumin solution, respectively. The structure of the identified feruloyloacetone was confirmed by MSn, HRMS and NMR data. The presented results are important for food processing as feruloyloacetone is formed during food products preparation and its biological activity has not been fully recognized.

We report an efficient protocol for tandem Pd-catalyzed intramolecular addition of active methylene compounds to alkynes, followed by subsequent cross-coupling with (hetero)aryl bromides and chlorides. The reaction proceeds under mild conditions, providing excellent functional group tolerance, including unprotected OH, NH2 groups, enolizable ketones, or a variety of heterocycles. Mechanistic studies point towards a catalytic cycle involving oxidative addition, intramolecular nucleophilic addition to the Pd(ii)-activated alkyne, and reductive elimination, with 5-exo-dig cyclization being the rate limiting step.