Chemistry

Due to the unique properties of titanium dioxide (TiO₂), titanium oxide catalysts hold significant potential for photo-oxidative processes involving organic substances in liquid media. The current research has focused on developing new preparation methods that enable the manipulation of the properties, structure, and geometric shape of catalysts to enhance their efficiency in targeted reactions. This study developed a method for preparing Ag-SiO₂-TiO₂/TiO₂-Ag layered structures with a spherical shape, featuring particle diameters ranging from 232 to 653 μm and mesopores of 2–20 nm. This was achieved by combining sol–gel and template synthesis methods. A comprehensive analysis of the obtained materials was conducted using methods such as X-ray phase analysis, micro-X-ray spectral analysis, X-ray microanalysis, and scanning electron spectroscopy. The photocatalytic properties were assessed by measuring the degree of decomposition of methyl orange in a model oxidation reaction under light radiation. The obtained spherical Ag-SiO₂-TiO₂/TiO₂-Ag layered structures demonstrated high efficiency in the photooxidation of methyl orange in the model reaction. Full article

The nucleus-independent chemical shift (NICS) criterion plays a significant role in evaluating (anti-)aromaticity. While being readily accessible even for non-computational chemists, adding ghost atoms for multi-points NICS evaluations poses a significant challenge. In this article, I introduce py.Aroma 4, a freely available and open-source Python package designed specifically for analyzing (anti-)aromaticity. Through its user-friendly graphical interface, py.Aroma simplifies and enhances aromaticity analyses by offering key features such as HOMA/HOMER index computation, Gaussian-type input file generation for diverse NICS calculations and corresponding output processing, NMR spectra plotting, and computational supporting information (SI) generation for scientific manuscripts. Additionally, NICS_⊥ is suggested for evaluating (anti-)aromaticity for non-planar or tilted rings. Pre-compiled executables for macOS and Windows are freely available online. Facilitate accessibility for users lacking programming experience or time constraints. Full article

Aqueous two-phase systems (ATPSs) have long been used for the facile and rapid extraction of biomolecules of interest. Selective partitioning of DNA is useful for nucleic acid purification and in the design of novel sensing technologies. This paper investigates the partitioning of a plasmid within a poorly understood ATPS comprising the polymers poly(ethylene glycol) (PEG) 35 kDa and Ficoll 400 kDa. The focus is placed on dissecting the compositional effects of the ATPS—that is, whether set concentrations of physiological ions or the polymers themselves can tune DNA phase preference and strength of partitioning. The work here uncovers the antagonistic effects of magnesium and ammonium ions, as well as the role that phase-forming polymer partitioning plays in plasmid enrichment. Testing the ions in conjunction with different ATPS formulations highlights the complexity of the system at hand, prompting the exploration of DNA’s conformational changes in response to polymer and salt presence. The work presented here offers multiple optimization parameters for downstream applications of PEG–Ficoll ATPSs, such as in vitro transcription/translation-based biosensing, in which performance is heavily dependent upon nucleic acid partitioning. Full article

Tyrosyl-DNA phosphodiesterases 1 and 2 (TDP1 and TDP2) are important DNA repair enzymes that remove various adducts from the 3′- and 5′-ends of DNA, respectively. The suppression of the activity of these enzymes is considered as a promising adjuvant therapy for oncological diseases in combination with topoisomerase inhibitors. The simultaneous inhibition of TDP1 and TDP2 may result in greater antitumor effects, as these enzymes can mimic each other’s functions. We have previously shown that usnic acid-based sulfides can act as dual inhibitors, with TDP1 activity in the low micromolar range and their TDP2 at 1 mM. The oxidation of their sulfide moieties to sulfoxides led to an order of magnitude decrease in their cytotoxicity potential, while their TDP1 and TDP2 activity was preserved. In this work, we synthesized new series of usnic acid-based sulfides and their oxidized analogues, i.e., sulfoxides and sulfones, to systematically study these irregularities. The new compounds inhibit TDP1 with IC₅₀ values (the concentration of inhibitor required to reduce enzyme activity by half) in the 0.33–25 μM range. Most sulfides and some sulfoxides and sulfones inhibit TDP2 with an IC₅₀ = 138−421 μM. In addition, the most active compounds synergized (×4) with topotecan on the HeLa cell line as well as causing dose-dependent DNA damage, as confirmed by Comet assay. Sulfides with the 6-methylbenzoimidazol-2-yl substituent (8f, IC₅₀ = 0.33/138 μM, TDP1/2) and sulfones containing a pyridine-2-yl fragment (12k, IC₅₀ = 2/228 μM, TDP1/2) are the most potent derivatives and, therefore, are promising for further development. Full article

Cholinesterases are enzymes that break down the neurotransmitter acetylcholine in the nervous system. The two main types are acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). AChE inhibitors are used to treat Alzheimer’s disease by increasing acetylcholine levels. BChE activity increases in later stages of Alzheimer’s, suggesting it might contribute to the disease. In previous experiments, it was found that a newly designed hybrid of galantamine (GAL) and curcumin (CCN) (compound 4b) decreases the activity of BChE in murine brain homogenates. Here, we explore this observation using molecular dynamics simulations. GAL and CCN were also studied for comparison. The structures of the complexes between the BChE and the ligands were predicted by molecular docking. Then, molecular dynamics simulations were performed to evaluate the stability of the complexes and the interactions between the ligands and the enzyme over a simulated time of 1 μs. All three ligands formed stable complexes with BChE. Compound 4b formed more hydrogen bonds and other interactions with BChE compared to GAL and CCN, suggesting a stronger binding affinity. The stronger binding of 4b to BChE might explain its superior anti-BChE activity observed in previous experiments. Full article

The utilization of dodecaborate boron clusters, [B₁₂X₁₂]²⁻ (X = Cl, Br, or I), as membrane carriers has been demonstrated recently, and their activity is known to be due to their superchaotropic nature. In this work, the mono-alkylation of [B₁₂Br₁₁OH]²⁻ to functionalize it with an aliphatic spacer was developed with a view to expanding the known chemical space of membrane carriers based on [B₁₂Br₁₂]²⁻. A new and improved facile route for the preparation of [B₁₂Br₁₁OH]²⁻, which is an important precursor to other [B₁₂Br₁₁OR]²⁻ species, is reported. Various alkoxylated [B₁₂Br₁₁O(CH₂)₅Z]²⁻ (Z = OH, N(CO)₂C₆H₄, CN and N₃) derivatives were prepared via a divergent synthesis based on [B₁₂Br₁₁O(CH₂)₅Br]²⁻. One of the newly synthesized compounds was utilized as a membrane carrier, and its impact on cell viability was examined. Full article

This paper studies the catalytic hydrogenation reduction of lignin-derived phenolic compounds, such as catechol, guaiacol (O-methoxyphenol), phenol, P-methylphenol, O-ethylphenol, O-ethoxyphenol, etc. The reaction system focuses on the catalytic performance of hydrodeoxygenation reactions involving the phenolic derivatives of the lignin depolymerization products catechol and guaiacol. A series of Al₂O₃-TiO₂ composite oxide supports with different Al/Ti ratios were prepared by a co-precipitation method, and a 5% Pd/Al₂O₃-TiO₂ bifunctional catalyst was prepared by an impregnation method and characterized with XRD, SEM, BET, NH₃-TPD, etc. Among these, the Pd/Al₂Ti₁ catalyst had the most excellent catalytic performance. At 100 °C and 2 MPa hydrogen pressure, the conversion of catechol was as high as 100%, and at 100 °C and 5 MPa hydrogen pressure, the conversion of guaiacol reached 90%. Full article

Long-range proton transfer in several conjugated proton cranes, originating from 7-hydroxy quinoline as a proton transfer platform, has been investigated theoretically by means of DFT and TD-DFT methodology. Major emphasis was given to their applicability to provide clean switching upon irradiation. The border conditions require the existence of a single enol tautomer in the ground state, which under excitation through a series of consecutive exited and ground state intramolecular proton transfer steps is transferred to the keto tautomer. It was shown that the most suitable candidates are based on using iso-quinoline, pyrimidine and 4-nitropyridine as proton crane units. Their suitability is a function of aromaticity changes, the basicity of the nitrogen atom from the proton crane unit and the structural effects originating from their conjugation with 7-hydroxy quinoline. Full article

The alkoxycarbonylation of styrene by palladium chloride is studied employing the density functional theory (DFT). Initially, [PdCl₃]^– reacts with methanol to form the methoxy-bound intermediate, which undergoes β-hydride elimination to form the key intermediate [PdCl₂H]^–. Then, a 1,2-insertion reaction to styrene takes place to form linear and branched alkyl coordinated with the Pd^II. Then, CO coordination followed by a 1,1-insertion reaction leads to the formation of acyl intermediate. Next, the methanolysis leads to the formation of esters. Previous reports with other catalysts suggested the intermolecular/intramolecular transition state (TS) formation with a high activation barrier, and this step was the bottleneck. To the best of our knowledge, this is the first time we have considered a two-step mechanism for the alcoholysis of the ester formation mechanism. After coordination with the metal, the methanol undergoes oxidative addition to form the Pd^IV square pyramidal intermediate, followed by reductive elimination to form the ester with regeneration of the metal hydride active intermediate. Deeper insight into the nature of bonding at the TSs is obtained through energy decomposition with natural orbital for chemical valence (EDA-NOCV) and quantum theory of atoms in molecules (QTAIM). Full article

Diradical character is one of the characteristic quantities of functional open-shell molecules. Prof. Nakano devotedly studied the relationship between diradical character and material properties of open-shell molecules; now, we can use the diradical character as a powerful tool for molecular material designs. It is still unclear how the open-shell molecules are affected by the interaction with the surface although the molecules have been immobilised for device applications. In the present study, the adsorptions of model diradical molecules with s-electrons on the MgO (001) and BaO (001) surfaces are investigated using approximate spin projected density functional theory with plane-wave basis (AP-DFT/plane-wave) to provide a systematic discussion of surface–diradical interactions. The accuracy of AP-DFT/plane-wave was verified by comparisons with the calculated results by NEVPT2. The computational error introduced by DFT calculations on the diradical state (spin contamination error) is reduced by the surface–diradical interaction. In addition, it is shown that (1) the diradical character is amplified by the orbital polarisation effects of oxide ions, and (2) the character decreases when the magnetic orbitals become electron-rich due to electron donation from the surfaces. The two effects are competing; the former is pronounced in Au systems, whereas the latter is pronounced in Ag systems. Full article

Imidazolium-based ionic liquids (ILs) have been regarded as green solvents owing to their unique properties. Among these, the melting point is key to their excellent performance in applications such as catalysis, biomass processing, and energy storage, where stability and operational temperature range are critical. The utilization of neural networks for forecasting the melting point is highly significant. Nevertheless, the excessive selection of descriptors obtained by density functional theory (DFT) calculations always leads to huge computational costs. Herein, this study strategically selected only 12 kinds of quantum chemical descriptors by employing a much more efficient semi-empirical method (PM7) to reduce computational costs. Four principles of data pre-processing were proposed, and the innovative use of a simulated annealing algorithm to search for the lowest energy molecular conformation improved accuracy. Based on these descriptors, a multi-layer perceptron neural network model was constructed to efficiently predict the melting points of 280 imidazolium-based ILs. The R² value of the current model reached 0.75, and the mean absolute error reached 25.03 K, indicating that this study achieved high accuracy with very little computational cost. This study reveals a strong correlation between descriptors and melting points. Additionally, the model accurately predicts unknown melting points of imidazolium-based ILs, achieving good results efficiently. Full article

Three new acylated benzophenone O-glycosides named aucherosides A–C (4–6), together with five known compounds such as mangiferin (1), maclurin-6-O-β-D-glucopyranoside (2), 1-O-galloyl-β-D-glucose (3), vanillic acid (7), and 5-hydroxy-2-isopropylchromone-7-O-β-glucoside (8), were isolated from the aerial parts of Hypericum aucheri Jaub. and Spach and identified with spectroscopic methods (1D and 2D NMR, and HRESIMS). Compounds 2, 4–6, 8, and previously isolated from the title plant aucherines A–C (9–11), were tested for hMAO-A and B inhibitory effects and neuroprotection. All tested compounds (1 µM) did not exhibit any inhibitory effect on hMAO-A and showed significant inhibitory activity against the hMAO-B enzyme. Notably, compound 8 demonstrated the strongest hMAO-B inhibition, approaching that of the positive control selegiline. At high concentrations (100 µM), all tested compounds showed no neurotoxic or pro-oxidant effects on rat brain synaptosomes, mitochondria, and microsomes. All tested compounds exhibited good neuroprotective and antioxidant activities in various neurotoxicity models (6-hydroxydopamine-induced neurotoxicity on synaptosomes, tert-butyl hydroperoxide-induced oxidative stress on mitochondria, and non-enzymatic lipid peroxidation on microsomes). The neuroprotective mechanisms of these compounds may include MAO-B inhibition, reactive oxygen species (ROS) scavenging, membrane stabilization, and preservation of reduced glutathione (GSH), the primary nucleophilic ROS scavenger. Full article

Hydrotalcite-like materials (OSA-LDH) were prepared used oil shale ash (OSA), which came from a thermal power plant area, as the main raw material. The characterization results of X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and thermogravimetric-differential scanning calorimetry (TG-DSC) showed that the prepared samples were mesoporous materials in a crystal state and were layered and contained lattice oxygen and a large number of surface hydroxyl groups. The adsorption property of the prepared samples was confirmed and evaluated by adsorption experiments with Pb²⁺ as the target pollutant. The adsorption process was in accord with the Langmuir isothermal adsorption equation, and the adsorption data fitted perfectly with the pseudo-second kinetic equation. The saturated adsorption capacity for Pb²⁺ was 120.92 mg·g⁻¹ at a temperature of 298 K and initial concentration of 300 mg·L⁻¹. The main adsorption mechanisms of OSA-LDH for Pb²⁺ were chemical bond cooperation and electrostatic bond cooperation. This paper aimed to not only prepare an economical and effective adsorbent to remove heavy metal ions from the solution but also provide a new path for the treatment and utilization of OSA so as to realize efficient waste resource utilization. Full article

Chiral electroactive materials have attracted attention for the effects of electrical magnetochiral anisotropy (eMChA) and chirality-induced spin selectivity (CISS). The combination of tetrathiafulvalene (TTF) with chiral moieties is one way to access chiral electroactive materials. In this paper, we have focused on the fused 2,3-dimethylcyclohexene (DMCh) ring as a substituent with chiral carbon atoms and without heteroatoms, which has not been used in the field of molecular conductors, and we synthesized a new TTF derivative (rac-DMCh-EDT-TTF). We have developed novel molecular conductors (rac-DMCh-EDT-TTF)₂X (X⁻ = PF₆⁻, AsF₆⁻ and ClO₄⁻), which have bilayer conducting sheets composed of the two crystallographically independent molecules. All salts exhibited semiconducting behavior from room temperature down to low temperatures, and a resistivity anomaly was observed at 180–250 K. X-ray structure analysis at 100 K and 263 K and molecular orbital calculations using the results of X-ray structure analysis indicated the emergence of a charge disproportionation between Layers 1 and 2 at the low-temperature phase. Full article

Background: Reflecting the increasing interest and research on living a healthy life as society ages, there has been a surge in attention and studies on photodamage. Probiotics have been studied for their ability to enhance skin integrity and provide protection from ultraviolet radiation (UVR). However, despite this, extensive research has revealed various issues and side effects, prompting increased interest in alternative options that can effectively and safely protect the skin. We focused on postbiotics as a promising solution for photodamage, aiming to demonstrate their potential as a safe and stable alternative to probiotics. Methods: We investigated papers on “skin aging” or “photoaging” and “probiotics” or “postbiotics” from 2013 to 2023 using the Web of Science, PubMed, and Scopus. Additionally, we compared and analyzed publications, authors, countries, keywords, and citations using the VOS viewer program. Results: According to our search results, the majority of papers on photodamage and probiotics were published in PubMed, with the United States leading in publication volume among countries. The most common keywords were “photodamage” and “skin”. The most cited paper recorded 470 citations. Furthermore, upon focused analysis of five papers on postbiotics and photodamage, postbiotics demonstrated preventive and protective effects against skin photodamage. Conclusions: Postbiotics for photodamage show potential as a safe and stable alternative to probiotics. However, research on postbiotics and photodamage remains limited, and additional studies and long-term tracking are essential to substantiate our claims. Full article

Alzheimer’s Disease (AD) is the most common form of dementia in individuals over the age of 65. There is no known prevention for the progression of the disease, although the FDA recently approved two drugs for AD. The exact etiology of AD is still under debate; however, it is commonly associated with the aggregation of amyloid-beta (Aβ) plaques in the brain. Recently some extended chalcones were reported to be potential anti-amyloidogenic agents. In this study, a larger library of extended chalcone analogs were synthesized with modifications on both rings. These were tested using the Thioflavin T fluorescence assay to measure their anti-Aβ aggregation properties. Three notably active compounds were further evaluated for potential neurotoxicity and neuroprotection using an MTT cell viability assay. These compounds were non-neurotoxic and displayed a trend toward neuroprotection. These were further assessed in a Drosophila melanogaster animal AD model. A forced climbing assay revealed statistically significant changes in flies’ movement by ~30% when fed these anti-amyloidogenic agents. Full article

Since the emergence of microfluidic devices, subtractive manufacturing techniques have dominated their production. Although the conventional manufacturing processes are well established, they come along with some disadvantages that limit the accessibility and hinder the further development of microfluidics. With the rise of additive manufacturing, researchers are focused on developing alternative fabrication methods to promote affordability and accessibility. This paper presents the opportunities and challenges of laser-based stereolithography printers for the fabrication of microfluidic equipment. Emphasis is put on the design and iterative prototyping process from the initial design idea to the final device. To print with adequate and sufficient geometrical accuracy and suitable material, the optimization of the printer’s performance is discussed. Regarding the design of multiphase microfluidics and its complex fluid behavior, suitable surface treatments, including an appropriate cleaning protocol, and coating strategies to make the printed channels either hydrophilic or hydrophobic are presented to ensure applicability. With these fundamentals of additive manufacturing in microfluidic fabrication at hand, the second focus of this contribution is on the application of a modular co-flow device and a monolithic flow-focusing device to generate droplets and slugs in different multiphase flow applications. The presented co-flow setup features a tapered capillary that affects the droplet and slug sizes due to differing diameters, with larger diameters leading to larger droplets and slugs and vice versa. Several design parameters for the flow-focusing device were evaluated to determine the influence of device design on multiphase flow formation. It was found that the diameter of the inlet for the dispersed phase has the greatest effect on the size of the resulting droplets and slugs and covers the largest range of adjustable sizes. Full article

The modification of carborane anion monocarba-closo-dodecaborate (1) with perfluoroalkyl groups enhances its solubility in fluorinated ethers. This novel approach achieves a degree of solubility that is unattainable by using traditional lipophilic modifications or boro–vertex functionalizations of 1. A spectroscopic analysis in combination with DFT calculations confirmed that these new anions retain their weakly coordinating nature and exhibit moderate chemical stability. Full article

As talk grows about billions or even trillions of dollars being directed toward potential “Net Zero” activities, it is imperative that the chemistry inherent in or driving those actions make scientific sense. The challenge is to close the mass and energy balances to the carbon and oxygen cycles in the Earth’s atmosphere and oceans. Several areas of climate science have been identified that chemists can investigate through methods that do not require a supercomputer or a climate model for investigation, most notably the following: (1) The carbon cycle, which still needs to be balanced, as many known streams, such as carbon to landfills, carbon in human-enhanced sewage and land runoff streams, and carbon stored in homes and other material, do not seem to have been accounted for in carbon balances used by the IPCC. (2) Ocean chemistry and balances are required to explain the causes of regional and local-scale salinity, pH, and anoxic conditions vs. global changes. For example, local anoxic conditions are known to be impacted by changes in nutrient discharges to oceans, while large-scale human diversions of fresh water streams for irrigation, power, and industrial cooling must have regional impacts on oceanic salinity and pH. (3) Carbon Capture and Storage (CCS) schemes, if adopted on the large scales being proposed (100s to 1000s of Gt net injection by 2100), should impact the composition of the atmosphere by reducing free oxygen, adding more water from combustion, and displacing saline water from subsurface aquifers. Data indicate that atmospheric oxygen is currently dropping at about twice the rate of CO₂ concentrations increasing, which is consistent with combustion chemistry with 1.5 to 2 molecules of oxygen being converted through combustion to 1 molecule of CO₂ and 1 to 2 molecules of H₂O, with reverse reactions occurring as a result of oxygenic photosynthesis by increased plant growth. The CCS schemes will sabotage these reverse reactions of oxygenic photosynthesis by permanently sequestering the oxygen atoms in each CO₂ molecule. Full article