Chemical Papers最新文献

In this study, carbazole-derived polymers were synthesized on ITO (indium tin oxide)-coated PET (Polyethylene terephthalate) via electrochemical reactions and conductivity measurements of the resulting polymeric films depending on temperature were actualized via four-point probe system. Their characterization processes were carried out by UV, FT-IR, NMR, TG-DTG, SEM analyses. Spectroelectrochemical measurements were performed for investigating their electrohromic properties. Homopolymer (P-6C) of carbazole-derived monomer as well as copolymer with thiophene were obtained by electrochemical polymerization method. Based on the CV measurements taken, the resulting copolymer film had good stability on the electrode surface. According to the thermal analysis of the homopolymer, its final degradation temperature was 297 °C and its residue amount at 800 °C was calculated as 18%. Comparisons of conductivity measurements were made depending on the temperature of the polymer films (25, 50 and 90 °C). The electrical conductivity values of the thiophene-carbazole derivative copolymer (6C-T) were decreased depending on the temperature (13.7 S/cm at 25 °C, 1.99 × 10^–2 S/cm at 90 °C). The conductivity of carbazole derivative homopolymer product (P-6C) was recorded to increase 10 times with increasing temperature. In the SEM image of P-6C a large and small, non-homogeneous surface with rounded corners was observed. Also, in the SEM image of the copolymer with thiophene (6C-T), small structures with rounded corners originating from thiophene and a non-homogeneous flat surface were seen. As a result, it has been revealed that the copolymer obtained from thiophene and carbazole derivatived compound could be used as a component in electronic devices due to its high conductivity value.

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The adsorption of hydrogen and methyl chalcogenides on pristine and B,N-doped graphene quantum dot models was investigated using B97-3c model to understand their interactions and orientations on the considered graphene surfaces. Molecular orientation was found to significantly influence adsorption energies, surpassing the impact of adsorption position. H₂S prefers an inverse-V configuration, while H₂Se preferred an L-shape configuration, with one hydrogen parallel to the pristine surface. Both methanethiol and methaneselenol prefer the carbon-chalcogen bond nearly parallel to the surface. Doping with boron-enhanced adsorption energies compared to pristine and N-doped GQDs. Non-covalent interaction (NCI) and atoms-in-molecules (AIM) analyses revealed weak interactions, primarily involving carbon atoms. However, in certain cases, interactions with the doped boron atom were revealed as the bond path. Selenium compounds exhibit less selectivity in their adsorption orientations, as evidenced by the smaller energy difference between their two most stable configurations compared to sulfide. Charge transfer was determined to play a minor role in these systems.

Herein, the combustion kinetics of low-grade coal through isothermal and non-isothermal analysis was investigated using thermogravimetric analysis in both N₂ and O₂ atmospheres. In the non-isothermal method, ignition temperature decreased from (236.45–202.11 °C) and burnout temperature (283.12–281.21 °C) was determined. The low-grade coal samples that underwent kinetic studies were initially treated with alkali and acid treatments. Experimental data were analyzed using the shrinking core model (SCM) and volume model (VM) using the isothermal method. As per results, the combustion curve shifted to higher temperature zones (600 °C, 700 °C, 800 °C, and 900 °C), resulting in an increased peak combustion rate. Higher combustion temperatures corresponded to elevated combustion rates and reduced total combustion times, indicating an improved coal combustion process. Among the models considered, the SCM emerged as the preferred choice for establishing conversion–time relationships and estimating reaction rate constants (k) across a spectrum of temperatures. Predictions based on apparent activation energy (E) and pre-exponential factor (A) were made using the Arrhenius equation. The apparent activation energy for isothermal combustion before and after chemical treatment using SCM (161.57–131.26 kJ/mol) and VM (179.67–138.52 kJ/mol) was determined. This study contributes valuable insights into the intricate dynamics of low-grade coal combustion, particularly emphasizing the significance of temperature variations on combustion characteristics.

The present work, describes the synthesis and antimicrobial evaluation of new selenium-NHC adducts (3a-e) and their corresponding benzimidazolium salts (2a-e). Specific synthetic approaches were employed, resulting in compounds with satisfactory stability under humid and aerated conditions. Characterization by spectroscopic methods confirmed structural changes upon selenium incorporation. Biological evaluations revealed varying antimicrobial and antifungal activities among the synthesized compounds. The results indicated that the benzimidazolium salts exhibited significantly enhanced antimicrobial and antifungal activities compared to reference agents. For instance, compound 2a demonstrated an IC₅₀ value of 6.25 µg/mL against Candida albicans, which was comparable to the reference Caspofungin (6.25 µg/mL). Similarly, compound 2e demonstrated strong antibacterial activity against Staphylococcus aureus, with an IC₅₀ value of 0.8 µg/mL, significantly outperforming the reference Ampicillin (1.56 µg/mL). In contrast, the selenium-NHC adducts exhibited moderate to minimal activity, with compound 3e showing the highest IC₅₀ value of 25 µg/mL against Staphylococcus aureus, but failing to surpass the activity of the reference agent. To explore the potential mechanism of action, molecular docking studies were conducted against Escherichia coli DNA gyrase and CYP51. The molecular docking results demonstrate that synthesized compounds exhibit significant binding affinity against both enzymes, indicating antibacterial and antifungal potential. These binding affinities suggest that these molecules could be effective dual-action antimicrobial agents.

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Investigating the anticancer and antimicrobial properties of nanoparticles (NPs) is essential due to the increasing demand for precise and targeted treatments against the new generation of resistant pathogens and cancer. This study uniquely demonstrates the green synthesis of anatase-phase TiO₂ nanoparticles using Sophora flavescens root extract, achieving developed multifunctional properties, including outstanding antibacterial, anticancer, and anti-inflammatory activities. Several characterization techniques, including X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and ultraviolet–visible (UV–Vis) spectroscopy, were employed to analyze the synthesized NPs. The photodegradation of Bromophenol Blue was modeled using a pseudo first-order kinetic model, with a maximum K1 occurring at 20 °C that continuously declines with increasing temperature, indicating a decrease in the degradation rate constants. The antibacterial activity was assessed using the Resazurin Microtiter-plate Assay (REMA), demonstrating significant inhibition of bacterial strains. The study concludes that TiO₂ NPs exhibit strong antibacterial efficiency, with inhibition zones measuring 15.7 mm for Staphylococcus aureus (gram-positive) and 13.2 mm for Escherichia coli (gram-negative). Additionally, the NPs were tested for anticancer properties against the MCF-7 breast cancer cell line, resulting in a cell viability rate of 62%. Biogenic metallic nanoparticles (TiO₂ NPs) demonstrate high efficacy in eradicating antibiotic-resistant bacteria due to their small size and bactericidal properties. Their stability and ability to penetrate bacterial cells enhance their antibacterial efficacy, particularly against gram-positive bacteria. To conclude, the growing demand for sustainable methods to synthesize multifunctional NPs is driven by challenges such as antibiotic resistance, environmental pollution, and the limitations of conventional anticancer treatments. The green synthesis of TiO₂ NPs using Sophora flavescens root extract presents an eco-friendly and efficient solution to these problems.

The molecular structure of hydrazinium phosphate (H₂DP) has been compared to the optimal structure determined by advanced quantum chemical methods, including DFT and MP2, using the 6-311G basis set. Hirschfeld surface analysis was employed to identify specific molecular interactions. The surface analyses of contours (dnorm, di, and de) and fingerprint plots revealed the contributions of various interactions: H…H (25.2%), O…H (67.3%), and H…N (7.4%). The electrostatic potential mapped on Hirshfeld’s surface highlighted the electrostatic complementarity during crystal packing. H₂DP’s broad transparency window in the UV–visible region makes it highly suitable for optoelectronic devices, as it allows efficient light transmission across a wide spectrum, enhancing performance and versatility. Using DFT and MP2 methodologies, we further investigated the H₂DP crystal structure. A HOMO and LUMO analysis was conducted to examine the electrostatic distribution and reactivity of the molecules within the crystal. The scatter graph explained the inter- and intra-fragment interactions, as well as the chemical bonding between ELF and NCI. Additionally, molecular docking studies were performed to assess H₂DP’s anticancer potential. Crystal growth, a surface-controlled process, involves the incorporation of solute molecules into surface lattice sites, resulting in the long-range order characteristic of crystalline materials. Molecular dynamics simulations evaluated the binding affinity of hydrazinium phosphate to the aromatase cytochrome P450 enzyme (PDB ID: 3EQM). The compound exhibited moderately strong binding affinity, suggesting its potential to modulate enzyme activity and its relevance in the conversion of androgens into estrogen during the final phase of steroidogenesis.

Many synthetic antiepileptic drugs are currently in use; however, their chronic usage often leads to a high incidence of drug resistance and unwanted side effects. This research highlights the significance of traditional medicine as an alternative approach to treating epilepsy. A methanolic combined root extract of Acorus calamus and Bacopa monnieri in a 1:1 ratio was prepared. Initially, computational-based molecular-level studies were conducted to examine the interacting phytoconstituents. Preliminary phytochemical screening determined the presence of alkaloids, glycosides, saponins, flavonoids, and terpenes. An animal study was performed for seizure induction, and various phases of epilepsy were recorded by observing the number of animals showing elimination of hind limb tonic extension (HLTE) or extension not greater than 90°. Treatment with 200 mg/kg (p.o.) and 400 mg/kg (p.o.) significantly (p < 0.05) decreased the flexion and extensor phases of convulsions compared to the standard drug phenytoin sodium. Additionally, docking and simulation studies revealed that the molecule 9,17-octadecadienal binds with an energy of −49.91 kcal/mol and is responsible for the observed activity. The toxicity profile of the phytoconstituents produced higher QPlogPo/w values (8.441) for the hydrophobic molecules, which may improve their capacity to penetrate the blood–brain barrier (BBB), allowing them to interact with specific CNS targets. The results of this study indicate that the root extracts of Acorus calamus and Bacopa monnieri have a significant antiepileptic effect against maximal electroshock seizure (MES)-induced seizures with negligible toxicity.

In recent years, the level of water resources around the world has been decreasing due to global warming, climate change and increasing consumption. In addition, the developing industry pollutes existing water resources. This situation negatively affects all living things on earth. In this study, the biosorption process of cationic dye methylene blue (MB), which was selected as a model dye compound from residual water, and sunflower tray biosorbent was discussed. It was seen that the amorphous structure of the sunflower tray was similar to the hexagonal structure. The process parameters were investigated to reach the highest biosorption efficiency. The highest efficiency (99%) was achieved at pH 6, biosorbent dose 10 g/L, dye concentration 10 mg/L and temperature 20 °C. It was determined that the biosorption process with an exothermic reaction was compatible with the Langmuir isotherm (R² = 0.96) and the pseudo-second-order (PSO) kinetic model (R² = 0.99). q_max was calculated as 117.6 mg/g. ΔG values suggested that the interaction between the sunflower tray and MB molecules was not spontaneous.