A simple smartphone-based detection method was developed for determining silicate in the presence of phosphate using the molybdenum blue reaction. The method is based on a reaction of analyte with ammonium molybdate to form molybdosilicic heteropolyacid. Amongst other ions, phosphorus(V) interferes this determination forming molybdophosphoric heteropolyacid in the same conditions. Oxalic acid was selected to decompose the interfering compound selectively. Then, molybdenum(VI) was reduced to molybdenum(V) using ascorbic acid forming silicomolybdenum blue. The reactions were performed in a cuvette (3 cm3). The smartphone and the PhotoMetrixPro® app were applied for the detection and analytical signal evaluation. Channel B of the RGB colour space model was selected for analyte determination, and the signal for the formed compound was measured after 9 min. The possibility of using smartphones with different camera specifications was also verified. Using the method, silicate was determined in the concentration range of 0.24–20.00 mg dm−3, with a precision of less than 4.9
We present the results of gas-phase detection of aromatic pollutants, benzene, toluene, ethylbenzene, and p-xylene (BTEX) using a modular optical sensor field prototype based on the quenching of the photoluminescence intensity of porous silicon sensing elements with various surface terminations. Four photoluminescence sensing elements, based on an as-prepared porous silicon (H-terminated Si surface), an oxidized porous silicon (–O– or –OH-terminated Si surface), and two functionalized porous silicon via light-induced hydrosilylation with allylbenzene and eugenol (phenylpropyl- and guaiacolpropyl-terminated Si surfaces), were tested, and basic sensor parameters—sensitivity and limit of detection—were evaluated. Strong interaction between benzene and toluene vapors with aryl-terminated surfaces led to very low photoluminescence responses, indicating a molecular recognition process based on π–π interaction.
A mechanochemical protocol for the copper-catalyzed Mannich reaction of 1,3-diacetoxyacridone with paraformaldehyde and secondary aliphatic amines has been developed. While conventional solution-phase stirring or heating failed to provide the target 4-aminomethyl derivatives, ball milling with copper balls efficiently promoted the transformation. Optimization of the model reaction with morpholine furnished the corresponding 4-morpholinomethyl derivative in up to 67
A stereo- and regioselective Mn(I)-catalyzed hydrosilylation of terminal alkynes is described. The hydrosilylation reaction selectively yields the thermodynamically less stable (Z)-alkenyl silane. A wide variety of aromatic and aliphatic alkynes were efficiently and selectively hydrosilylated. The reactions proceed with catalyst loadings of 1–2 mol
In this research, the synthesis of pyrano[2,3-d]pyrimidines and 1,2,3-triazole-linked pyrano[2,3-d]pyrimidines via multi-component reaction of 1,3-dimethylbarbituric acid, malononitrile, and aryl aldehydes/1,2,3-triazole-4-carbaldehydes catalyzed by ZnCl2/urea as a deep eutectic solvent in EtOH at 80 °C is reported. The principal merits of this approach include the utilization of an environmentally benign solvent, the accessibility of inexpensive starting materials, simple set-up, operational simplicity, and the facile isolation of pure products in high yields.
Compared to other isocyanides, (N-isocyanoimino)triphenylphosphorane (NIITP) is an air-stable, moisture-stable, safe, easy-to-handle, odorless, and commercialized solid that is recognized as an appealing reagent for the synthesis of heterocyclic compounds. NIITP-based multi-component reactions have attracted considerable attention from chemists due to their synthetic potential, one-step, atom efficiency, and creation of molecular diversity. Many bioactive heterocyclic molecules, such as oxadiazoles, triazoles, pyrazoles, and pyrrolidine-2,5-diones can be efficiently synthesized from NIITP. Multi-component reactions of NIITP are typically carried out with carboxylic acids, aldehyde/ketone and amine segments. In new multi-component reactions, aldehyde or imine electrophiles are replaced by carbodiimides, activated isocyanates or acetylene dicarboxylates, and Meldrum’s acid, β-diketones and 4(3H)-quinazolinones are used instead of carboxylic acid, leading to the synthesis of new heterocyclic compounds. NIITP also participates in various functionalization reactions, providing a series of functionalized molecules. Given the unique and versatile functionality of this precursor, in this review, we have described transformations of NIITP into functionalized heterocycles, since 2000.
Texturing is a convenient and versatile strategy to engineer the properties of a surface. In this study, the combination of photolithography with dynamic covalent bonds facilitates the fabrication of positive-tone surface patterns from a photopolymer. Selective photoactivation of a photolatent base catalyst in a 3D covalently crosslinked thiol-ene network allows for a spatially controlled solvent-assisted transesterification approach (alcoholysis). The photoactive resin is cured with visible light (450 nm), which makes it processable via vat photopolymerization. Furthermore, orthogonality between the curing and the activation reaction of the transesterification catalyst, which is activated using light with a different wavelength (405 nm), is ensured. Micropatterns that aim to affect or modify the friction properties are inscribed into the surface by selective light exposure using a photomask. The tribological behavior was evaluated in a ball-on-plate (BOP) measurement setup, where thiol-ene films with line or dimple surface patterns exhibit a significant increase in the coefficient of friction (COF) compared to the non-textured polymer films.
In this study, three new cationic bis(NHC)gold(I) hexafluorophosphate complexes, with the formula [Au(NHC)2]PF6, were synthesized from the corresponding N-heterocyclic carbene (NHC) silver complexes via transmetallation, with high yields achieved. The compounds were characterized using 1H NMR, 13C NMR, FT-IR, MALDI-TOF MS, and elemental analysis methods. Their antimicrobial properties were tested against pathogenic strains of Staphylococcus aureus, Bacillus cereus, Salmonella typhimirum, and Escherichia coli and against fungus Candida albicans. Analysis of the inhibition zone and minimum inhibitory concentration data revealed that the synthesized compounds exhibit moderate and selective antimicrobial activity, demonstrating a clear preference for Gram-positive bacteria. The studies concluded that the gold(I) complex containing the 1-benzyl-3-(2,5-dimethylbenzyl)benzimidazolin-2-ylidene displayed the most potent antimicrobial and anticancer activity.
The study presents a comprehensive multianalytical investigation of thirteen eighteenth-century inorganic pharmaceutical residues originating from the exceptionally preserved Baroque pharmacy of the Capuchin monastery in Prague. Since the historical Latin signatures on the majority of apothecary jars were only partially preserved or completely missing, the true chemical identities of the contents were largely unknown. We employed a combination of non-destructive, sample-conserving structural and phase analyses (Raman spectroscopy, DRIFTS, and PXRD) alongside destructive quantitative methods (ICP-MS, UV/Vis spectrometry, and CZE). This methodology successfully elucidated the true composition of all samples, revealing a diverse array of natural minerals (e.g., tremolite, goethite, hydromagnesite, tschermigite) and synthetically prepared compounds (e.g., potassium sulfate, potassium hydrogen tartrate, potassium sodium tartrate). The analyses highlighted intriguing historical pharmaceutical practices, including the possible substitution of laborious synthetic preparations with visually similar natural minerals, the misidentification of rare minerals (tschermigite for alum), and the rapid adoption of newly discovered medicines (Seignette salt). Furthermore, the study demonstrates that while non-destructive spectroscopic and diffraction techniques are vital for molecular and phase identification, their integration with quantitative elemental and ionic analyses is essential for fully resolving complex pharmaceutical mixtures, identifying trace impurities, and authenticating historical materia medica.
Plant-derived indigoid dyes, such as indigo and indirubin, exhibit remarkable optical and chemical properties that have fascinated researchers for centuries. In recent years, computational chemistry has become an indispensable tool for unraveling the molecular intricacies underlying their color, stability, and spectroscopic behavior. This review provides a critical synthesis of how diverse computational methods—including Density Functional Theory (DFT), Time-Dependent DFT, Molecular Dynamics (MD), and hybrid QM/MM approaches—have been applied to indigoids. These techniques enable the prediction and rationalization of UV–Vis spectra, vibrational modes, and NMR shifts, offering insight into structure–property relationships and environmental influences such as pH, solvent polarity, and substrate binding. Special attention is given to excited-state processes like ESIPT and internal conversion, which underpin indigo’s exceptional photostability. Additionally, computational strategies for modeling dye aggregation, tautomerism, and degradation pathways are discussed, demonstrating the synergy between theoretical predictions and experimental observations. The review highlights the role of computational tools not only in heritage science and dye chemistry but also in guiding the design of novel derivatives and sustainable applications. Future directions point toward integrating machine learning, advanced multiscale simulations, and enhanced benchmarking to further refine our understanding and expand the utility of indigoid systems in both traditional and emerging technological contexts.
This paper describes the determination of Ag nanoparticles (AgNPs) in toothpaste, hand soap, shampoo, and shower gel samples by single-particle inductively coupled plasma mass spectrometry. The main focus of our study is the sample preparation and stabilization of AgNPs for the determination of their size and particle number concentration. Special focus was given to the study of extraction agents for toothpaste samples; 0.1
Determination of a compound’s logP and pKa is advantageous in early stages of drug discovery. High pressure liquid chromatography (HPLC) is a viable, high throughput tool that is well-suited for such applications. The advantages stem from the minimal required analyte quantity and the ability to analyse samples of low purity and low water solubility. Determination of logP and pKa via HPLC often utilises reversed phase mode, leveraging the fact that the analyte’s ionisation state affects its hydrophobicity and therefore retention. Estimation of both parameters can be performed under either isocratic or gradient elution, applying linear solvent strength theory. Hereby, we present a novel mobile phase blending method aimed to fully automatise the logP and pKa determination process. The method uses buffer blending by pumps to produce mobile phases in the range of pH = 2.5–8.6 within the liquid chromatography system. A positive correlation was observed between our determined logkw values and the experimental logP found in literature, for a series of drug compounds. The pKa estimation shows satisfying results in isocratic measurements and solely aqueous mobile phase. The method enables a linear pH gradient generation, likewise applicable for pKa determination.
The emergence of SARS-CoV-2 has created a global medical crisis. Among potential therapeutic targets, the main protease (Mpro) of this causative virus is one of the most extensively studied for drug development. In this study, molecular modeling approaches including drug-likeness assessment, pharmacokinetics (ADME) prediction, toxicity evaluation, molecular docking, and molecular dynamics (MD) simulation were integrated to explore potential inhibitors against SARS-CoV-2 Mpro. From an initial pool of 65 phytochemicals derived from the antipyretic remedies Ya Ha Rak and Ya Khiao Hom, 30 compounds satisfying drug-likeness and pharmacokinetic criteria were selected for further evaluation. Docking studies identified isocodonocarpine (ISO) and sophoronol (SOP) as top candidates, demonstrating favorable docking scores of – 35.56 and – 37.66 kJ/mol, respectively, with strong interactions involving the catalytic residue C145. MD simulations revealed stable protein–ligand complexes, supported by strong hydrogen bonds and van der Waals interactions, while binding free energy calculations using the MM-PBSA approach further validated their high binding affinities. These findings suggest that ISO and SOP are promising candidates for SARS-CoV-2 Mpro inhibition, warranting further validation through in vitro and in vivo studies. This work provides valuable insights for developing effective antiviral drugs targeting SARS-CoV-2 Mpro.
This study presents a comprehensive, systematic evaluation of the stability of guaifenesin, a well-known expectorant drug, spanning an extraordinary real-time aging period of up to 72 years. A unique collection of seventeen authentic historical pharmaceutical preparations, manufactured in the former Czechoslovakia and the Czech Republic between 1954 and 1997, was analyzed using an optimized RP-HPLC method coupled with UV and mass spectrometry detection. A forced degradation study was conducted to evaluate the hydrolytic and oxidative stability of guaifenesin under various stress conditions. Hydrolytic cleavage was not observed, whereas oxidative stress yielded significant decomposition. Using HR-MS/MS, the primary oxidative degradant was conclusively identified for the first time as 3-(2-hydroxyphenoxy)propane-1,2-diol. Quantitative analysis of historical samples revealed that the guaifenesin content closely matched the declared values in all solid and liquid formulations, demonstrating that this active pharmaceutical ingredient possesses an outstanding shelf-life. Remarkably, even liquid dosage forms manufactured 72 years ago showed no significant signs of decomposition.
An authentic sample of the traditional North Korean alcoholic beverage “Kaesong Koryo Insam Wine,” containing a whole submerged ginseng root and bottle-aged for at least 12 years, was subjected to a comprehensive chemical and volatile organic profiling. Gas chromatography with flame ionization detection revealed an ethanol content of 26.8
Traditional complexing agents are highly effective but environmentally persistent, leading to a growing interest in biodegradable alternatives. However, many of these alternatives remain insufficiently characterised. In this study, capillary electrophoresis was employed to characterise four complexing agents: two conventional ligands, ethylenediaminetetraacetic acid and hydroxyethylidenediphosphonic acid, and two biodegradable substitutes, iminodisuccinic acid and ethylenediaminedisuccinic acid. The thermodynamic dissociation constants (pKa) and limiting ionic mobilities were determined by measuring effective mobilities across a series of background electrolytes with varying pH and constant ionic strength. The resulting pKa values and limiting mobilities were integrated into the PeakMaster software database to evaluate their predictive reliability. Computational simulations were validated against experimental separations using both indirect UV and contactless conductivity detection. Experiments utilising contactless conductivity detection at alkaline pH (8.4 and 8.6) showed higher consistency with the theoretical model.
Under certain conditions, metal surfaces undergo chemical passivation or corrosion. By selecting a suitable electrolyte, oxidation processes can be used to visualize latent fingerprints. Latent fingerprints were deposited on clean metal substrates (copper, brass, and aluminium), and an electrolytic method was evaluated using Britton-Robinson buffer at pH values of 2, 7, and 12, with and without methylene blue. The visualization efficiency was evaluated using a stereomicroscope as a function of deposition time, and the developed latent fingerprints were further characterized by SEM. The best contrast was achieved on brass and copper at neutral pH of Britton-Robinson buffer without methylene blue, while for aluminium, under acidic conditions. Methylene blue was effective only under certain conditions; otherwise, it caused staining or blurring of ridge details. This simple and low-destructive method shows the potential for latent fingerprint visualization on metals and offers scope for further optimization in forensic applications.
The article addresses the challenge of chemophobia—the long-lasting, irrational fear of chemistry and chemical substances—by proposing a shift from defensive communication to the proactive construction of an “ecosystem of desire”. While recent data show that young students often rate their knowledge of chemistry highly, very few express an interest in pursuing it as a career, threatening a future shortage of bright minds needed to solve major societal problems. Furthermore, public trust in chemistry is declining, and chemistry continues to suffer from a negative public image. Chemophobia is not merely a deficit of knowledge, but a complex “ecosystem of fear” embedded in wider cultural, emotional, and institutional patterns. This is evident in medical settings, where fear of “chemicals” disrupts treatment choices, in education, where decontextualized teaching and anxious educators reproduce distrust, and in consumer behavior, where a romanticized “return to nature” leads to biased risk perceptions and misleading food labeling. Industrially, a negative image can even undermine the political legitimacy of essential foundational industries. To counteract this, we advocate that the chemical community build an “ecosystem of desire”—a network of positive experiences, institutional openness, visible role models, and compelling narratives that frame chemistry around curiosity, creativity, care, and future-oriented hope. Effective communication must rely on four key principles: (1) telling clear stories, (2) acknowledging the public’s emotional climate, (3) adapting messages to diverse audiences, and (4) engaging proactively before being forced into self-defense. Crucially, this requires the participation of a cohesive, diverse chemical community. Drawing on Kant’s distinction between communio and commercium, we criticize rigid disciplinary boundary policing and advocate for internal reciprocal recognition among pure researchers, biochemists, chemical engineers, and educators. Finally, a historical vignette of Giacomo Casanova illustrates how chemical facts become socially powerful when embedded in compelling human narratives. Ultimate success against chemophobia depends on transforming the discipline from a science people merely need into one they want to belong to.
We report the first demonstration of an ultrasound-assisted, SnCl2·2H₂O-catalyzed one-pot green synthesis of ten 3,4-dihydropyrimidin-2(1H)-one (DHPM) derivatives via the Biginelli reaction of various aromatic aldehydes with ethyl acetoacetate and urea in ethanol at 30 °C. The optimized protocol utilizes ultrasound irradiation to significantly accelerate reaction rates, yielding DHPMs in excellent isolated yields (79–98
Cycloaddition reaction of 1-alkyl-1,2-diphospholes with alkynes is regarded as a new way for the synthesis of pentasubstituted phosphinines. The [4 + 2] cycloaddition of 1-ethyl-3,4,5-triaryl-1,2-diphosphacyclopenta-2,4-diene to bis(2-thienyl)acetylene gives new 2,3-(2-thienyl)-4,5,6-triaryl-1-phosphinines along with formation of ethylphosphinidene [:P–Alk].
