Turkish Journal of Chemistry最新文献

Quinoline derivatives have garnered significant attention owing to their wide range of biological activities, particularly their anticancer potential. In this study, six novel 4-aminoquinoline derivatives incorporating a phenylalanine methyl ester moiety were synthesized and structurally characterized. The cytotoxic activities of the synthesized compounds were assessed against A549 and MCF-7 cancer cell lines, along with the noncancerous NIH3T3 fibroblast cell line. Compounds 4d and 4e displayed potent anticancer activity with low IC₅₀ values, while exhibiting negligible toxicity toward normal cells. Moreover, these compounds exhibited moderate inhibitory activity against EGFR. Molecular docking studies were conducted to elucidate the binding modes of compounds 4d and 4e at the EGFR active site. To better elucidate their electronic structures and reactivity profiles, density functional theory (DFT) calculations were carried out to determine frontier molecular orbital energies, global reactivity descriptors, dipole moments, and molecular electrostatic potential (MEP) maps. Theoretical data were correlated with the experimental biological activities, revealing consistent trends, particularly among the most active compounds. Furthermore, theoretical NMR chemical shift calculations were performed for the synthesized compounds.

In this work, various aromatic monocarboxylic and dicarboxylic acids were subjected for the first time to a vinylation reaction with acetylene under heterogeneous catalytic conditions using catalytic systems based on silicon oxycarbide supported on silicon carbide (SiC): zinc silicon oxycarbide (Zn/SiOC), zinc oxide silicon oxycarbide (ZnO/SiOC), and nickel silicon oxycarbide (Ni/SiOC). The influence of the nature of the starting materials, temperature, reaction duration, solvent, and catalyst type on the yield of vinyl esters was investigated. The vinylation reaction of aromatic carboxylic acids with acetylene was carried out at 1:2 molar ratio, using a Zn/SiOC-50 catalytic system at a loading of 10 mol% relative to the initial aromatic carboxylic acid, in a N,N-dimethylformamide (DMF) solution at 150 C for 12 h, resulting in high yields of vinyl esters. Under these heterogeneous catalytic conditions, the vinylation reaction afforded the following vinyl esters: benzoic acid (80%), 4-methylbenzoic acid (77%), 4-methoxybenzoic acid (70%), 4-fluorobenzoic acid (83%), 4-tert-butylbenzoic acid (65%), 4-chlorobenzoic acid (85%), divinyl esters of ortho-phthalic acid (88%), and terephthalic acid (91%). The structures of the synthesized vinyl esters were confirmed by Fourier-transform infrared (FTIR), proton nuclear magnetic resonance (¹H NMR), carbon-13 nuclear magnetic resonance (¹³C NMR), and chromatographic-mass spectral (MS) analyses.

Levothyroxine, as a thyroid-stimulating hormone, is the primary drug used for hypothyroidism treatment, but it has poor bioavailability. Selenium (Se) plays an important role in regulating thyroid function; moreover, selenium nanoparticles (SeNPs) offer advantages over other Se forms. Liposomal delivery systems, especially those coated with polyethylene glycol (PEG), can increase the oral bioavailability of drugs and provide controlled release. In our research, as described in this paper, we aimed to develop an orally applicable liposomal delivery system to achieve enhanced treatment of hypothyroidism with SeNP characteristics, controlled levothyroxine release, and improved bioavailability of both drug and SeNPs. The SeNPs have been prepared using ascorbic acid with a hydrothermal method and an ecofriendly approach. The SeNPs have been 75-100 nm in size and have shown a Fourier transform infrared spectroscopy (FTIR) peak at 479 cm^-1, which corresponds to the stretching and bending vibrations of the Se-O. Liposomes have been easily synthesized using the thin film technique, and levothyroxine and SeNPs have both been loaded by encapsulation. The encapsulation yield of levothyroxine into liposomes has been found to be 91.4%, which has been calculated spectrophotometrically. The SeNP content in the liposomes has been determined using inductively coupled plasma mass spectrometry (ICP-MS). The SeNPs and drug-encapsulated liposomes have been coated with PEG for potential oral usage, and their structure has been verified with FTIR. The levothyroxine release from the liposomal form has been higher in a pH 6.8 buffer than that in a pH 7.4 buffer, and the release has been observed to be in a controlled and constant manner with diffusion characteristics. Thus, we suggest that a PEG-coated liposomal delivery system containing both levothyroxine and SeNPs has been developed successfully, and it could be a promising approach for enhanced oral treatment of hypothyroidism.

Rapid technological advancement has increased energy consumption, environmental pollution, and climate change, necessitating sustainable sources of energy. Solar energy is appealing because it is renewable and has minimal environmental impact. However, the complex fabrication and high costs of conventional silicon solar cells have driven research into alternative technologies like perovskite solar cells (PSCs). This study investigates the use of electrospun nickel oxide (NiO)/carbon nanofibers as efficient hole-transporting layers in PSCs. NiO nanomaterials were synthesized via coprecipitation and integrated into polyvinyl alcohol nanofibers through electrospinning at an optimized concentration of 20 g/L, producing uniform nanofibers with mean (SD) diameter of 136 nm (20). The electrospun nanofibers were calcined to convert them into NiO/carbon nanofibers. The structural and chemical properties of nanofibers were characterized using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared (FTIR) and Raman spectroscopy, thermogravimetric analysis, and photoluminescence spectroscopy. These NiO-based nanofibers were used as hole-conducting layers in constructing fluorine-doped tin oxide (FTO)/titanium dioxide peroxide P25 (TiO₂)/perovskite/NiO-carbon/FTO solar cells, achieving a maximum efficiency of 5.96%. This research shows the potential of NiO-based hole-conducting layers in enhancing PSC efficiency. Optimizing NiO concentration and electrospinning time can significantly improve the conductive properties and performance of PSCs.

Oxidation of alkanes remains a central challenge in catalysis due to the high activation barriers of C-H bonds and the thermodynamic favorability of complete oxidation. Palladium oxide (PdO), particularly its (101) facet, is known for its high reactivity in alkane oxidation, which is attributed to its coordinatively unsaturated palladium (Pd) and O atoms. In this study, we investigate the effect of silver (Ag) incorporation on the oxidation behavior of propane over PdO(101) using temperature-programmed reaction spectroscopy (TPRS) under controlled conditions. While pristine PdO(101) exhibits complete oxidation of propane with CO₂ and H₂O desorption at high temperatures (approximately 475 K), Ag incorporation induces a new CO₂ desorption peak at significantly lower temperatures (approximately 330 K). This shift is attributed to the formation of new active sites at the Ag-PdO(101) interface. Quantitative analysis reveals that low-temperature activity correlates with Ag coverage, while overall CO₂ production decreases, suggesting a redistribution of reactivity rather than an increase in active surface area. Activation energy estimations using the Redhead method confirm that C-H bond activation becomes more facile at the interface, with a 46 kJ/mol reduction compared to pristine PdO(101). These findings demonstrate that incorporating a less reactive metal such as Ag into PdO surfaces not only modifies the reaction energetics but also enables the design of bimetallic catalysts with improved selectivity for partial oxidation reactions.

This study aimed to investigate the catalytic performance of gold nanoparticles (AuNPs) obtained by using ginger and carob antioxidant plants as reducing and stabilizing agents. In the first stage of the study, AuNPs were successfully produced using these herbal extracts via a green synthesis method, without the need for toxic chemicals, in a sustainable, economical, rapid, energy-efficient, and easy way. In the second stage, the structural analysis and catalytic applications of the obtained AuNPs were investigated. Advanced techniques such as Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), UV-Vis spectroscopy, and energy dispersive X-ray spectroscopy (EDX) were used to elucidate the morphological, optical, and structural properties of AuNPs in detail. In UV-Vis analyses, the observation of characteristic surface plasmon resonance (SPR) peaks in the range of 532-540 nm confirmed that AuNPs were successfully synthesized. In the catalytic application dimension of the study, the efficiency of the obtained AuNPs in the degradation of common industrial dyes such as rhodamine B, methyl orange, and methylene blue with NaBH₄ reduction was investigated. The nanoparticles exhibited high catalytic performance in the reduction of the dyes in question, and the reaction processes were completed in a short time (approximately 8-12 min). The kinetics of these reduction reactions were evaluated within the framework of the Michaelis-Menten kinetic model; important parameters such as reaction rate constants (k) and half-life (t_1/2) were calculated. The calculated values of K_M = 3.45 mg L^-1 and v _max = 0.78 mg L^-1 min^-1 for Gng-AuNPs reveal that this catalyst exhibits higher affinity for dyes and operates more efficiently at lower concentrations. The findings obtained reveal that AuNPs synthesized using plant antioxidants not only offer an environmentally compatible production process, but also, due to their high catalytic efficiency, provide a potential alternative for the removal of environmental pollutants. In this respect, these nanoparticles offer innovative and applicable solutions in the field of sustainable chemistry and environmental technologies.

The Hückel aromatic and Möbius aromatic compounds, consisting of topologically different arrangements of adjacent benzene rings in the polycyclic aromatic hydrocarbon (PAH) family, have long attracted interest in both synthesis and theoretical chemistry. Among these, [n]-azene and [n]-circulene derivatives are more thoroughly explored due to their simple architectures and more accessible synthesis pathways. However, there are active ongoing studies on the synthesis of both [n]-helicene and expanded [n]-helicene structures, as well as Möbius circulenes, which are Möbius isomers of [n]-circulenes. In this regard, there is limited information available on both the experimental and theoretical characterization of the synthesized molecules. In this study, we employed Density Functional Theory (DFT) to investigate the thermodynamic stabilities, electronic structures, and optical and molecular properties of both synthesized and hypothetical expanded [n]-helicenes and Möbius [n+1]-circulenes. Particular emphasis was placed on the racemization barriers-an essential and tunable parameter in the design of functional chiral materials and their molecular properties. The racemization energies were computed for pristine, functionalized, and heteroatom-doped variants of expanded [n]-helicenes. Given their critical role in determining configurational stability, the racemization barriers are crucial for the material applications of functional chiral molecules and especially relevant to applications involving [n]-helicenes or helicene-like structures.

Green synthesis of silver nanoparticles (Ag-NPs) was carried out with sumac fruit extract using a microwave-assisted (MWA) method and a traditional method (TDM). The properties of nanoparticles synthesized by both methods were characterized and compared.Although both methods are environmentally friendly, the MWA method was faster, more efficient, and economical. When creating Ag-NPs, variables like temperature, pH, reaction duration, extract concentration, and silver ion concentration were considered. The production of Ag-NPs was confirmed by ultraviolet-visible spectra that displayed the surface plasmon resonance band centered at 433 and 436 nm in the MWA and TDM techniques, respectively. The results of the scanning electron microscopy/energy-dispersive X-ray spectroscopy analysis indicated that the nanoparticles were spherical in structure and that the amount of Ag was significantly higher than that of other elements. According to transmission electron microscopy analysis, particle sizes were 22 nm with the TDM method, while particle sizes were 41.85 nm with the MWA method. However, the MWA method had more uniformly dispersed and homogeneous particle sizes. Conductivity measurements of Ag-NPs solutions were obtained following each cycle of washing. Subsequent to 3 cycles of washing, the conductivity approached that of deionized water, indicating the effective removal of unreacted ions. In our study, a significant increase was detected in the antibacterial and antifungal activities of Ag-NPs. Furthermore, both Ag-NPs inhibited the proliferation of HT-29 cells and showed a selective anticancer effect against intestinal cancer cells without showing toxicity (all cell viability values >70%) to healthy control L929 fibroblast cells. This study is the first comparative analysis of TDM and MWA methods using sumac for both antimicrobial and anticancer assessment.

Nanoporous silver (NPS) films, characterized by a 3-dimensional bicontinuous structure of interconnected nanopores and ligaments, have found widespread use in spectroscopy, plasmonics, solar cells, catalysis, and chemical sensing. Traditionally, NPS films are fabricated via chemical dealloying, where a less noble metal (e.g., Cu or Al) is selectively removed through harsh chemical etching. However, residual traces of these metals can adversely affect the performance of NPS thin films in applications such as plasmonics and catalysis. This paper reports a one-pot, liquid crystal-templated method for synthesizing ultrapure NPS thin films at room temperature for the first time. The process begins with the preparation of an LLC composed of a nonionic surfactant and AgNO₃ that is then coated onto solid substrates. Exposure of the LLC film to ultraviolet light facilitates the in situ synthesis of Ag nanoparticles within the liquid crystal film. Subsequent solvent washing removes the surfactant molecules and any unreacted metal ions, yielding NPS films comprised of densely packed Ag nanoparticles on glass substrates. The resulting NPS films feature a 3-dimensional structure with uniformly distributed, interconnected nanopores. Synthesized under ambient conditions and scalable over large areas, these ultrapure NPS films present a highly promising platform for advanced applications in catalysis, spectroscopy, plasmonics, and biosensing.

In this study, gamma-irradiated graphene oxide was incorporated into novel pH-responsive hydrogels. The biopolymer kappa carrageenan was blended with polyvinyl alcohol in a silane crosslinked biopolymer, and the effect of gamma irradiation dosage was studied. Nonhazardous tetraethoxysilane (TEOS) was used as a crosslinker. The hydrogels were characterized with chemical and thermal analysis, scanning electron microscopy, and structural analysis using a variety of analytical tools. The swelling behavior of fabricated hydrogels was assessed in various solution media. As the pH of the media increased, the swelling ratio of hydrogels decreased. All fabricated hydrogels had a high swelling ratio at acidic and neutral pH levels, with a decrease in swelling observed at basic pH. The pH-sensitive response at pH 7 make these hydrogels of potential use for controlled injectable-based drug delivery. Hydrogels with the highest swelling percentage were successfully loaded with letrozole (LTZ) to investigate the release mechanism. The drug release test was conducted in PBS and it showed that hydrogel released the LTZ in a regulated manner up to 99% in 4 h. These findings suggest that the hydrogels could serve as intelligent, responsive materials for controlled drug delivery and other biomedical applications at physiological pH.