Turkish Journal of Chemistry最新文献

In processes such as electrodialysis, the applied electrical potential is constrained by concentration polarization at the membrane/solution interface. This polarization, which intensifies at higher current densities, impedes ion transport efficiency and may lead to problems such as salt precipitation, membrane degradation, and increased energy consumption. Therefore, understanding concentration polarization is essential for enhancing membrane performance, improving efficiency, and reducing operational costs. This study investigates the impact of ammonia buffer (NH₄ ⁺/NH₃) on sulfate ion transport through anion-exchange membranes with a particular focus on limiting current density and concentration polarization under constant current conditions. The findings demonstrate that ammonia effectively eliminates concentration polarization and enhances chemical reactions at the membrane interface. Notably, the plateau region was absent in the current-voltage curves, as was the transition time in the chronopotentiograms. Furthermore, the Warburg impedance arc in the Nyquist plot of the electrochemical impedance spectra was absent in both limiting and overlimiting current regions and the increasing dominance of the Gerischer arc was registered. At an ammonia concentration of 0.1 M, the influence of concentration polarization on mass transport was effectively mitigated, enabling sulfate counterions to pass through the membrane without encountering concentration polarization. The addition of ammonia catalytically accelerated the proton-transfer reactions, which accelerated the water dissociation reaction at earlier polarization stages, preventing the formation of diffusion boundary layers and facilitating the transport of sulfate counterions through the AMX anion-exchange membrane. As a result, the polarization plateau disappeared and the overlimiting current region shifted closer to the ohmic region, all without affecting the limiting current density (j _lim ).

The development of ultraviolet (UV) shielding materials is of great importance to protect human health and prevent the degradation of organic matter. However, the synthesis of highly efficient UV shielding polymer nanocomposites is currently limited by the agglomeration of inorganic anti-UV nanoparticles (NPs) within the polymer matrix and the limited absorption spectrum of UV shielding agents. In this study, highly effective manganese doped carbon quantum dots@halloysite nanotube composites (Mn-CDs@HNTs/PAS) were successfully synthesized by loading manganese-doped carbon quantum dots (Mn-CDs) into UV shielding effective halloysite nanotubes (HNTs) via the solvothermal method, followed by polymerization modification (PAS). The results show that inorganic NPs are evenly dispersed into the polymer matrix. The resulting UV shielding film prepared by mixing Mn-CDs@HNTs/PAS composites with polyvinyl chloride (PVC) shows enhanced UV absorption and thermal stability compared with pure PVC film. It thus appears that Mn-CDs@HNTs/PAS composites have a promising future in UV protection.

A novel silica-based material (SBM), synthesized from chemically-, thermally-, and mechanically-treated blast furnace slag (TBFS), was examined for its batch-mode lead adsorption capacity based on various parameters. Physicochemical examinations revealed that the formulation of the new SBM consisted mainly of silica, which represented 81.79% of its total composition. After modification, the measured specific surface area changed significantly, from 275.8 to 480.13 m²/g, with a point of zero charge (PZC) of approximately 3.4 on the pH scale. The experiment revealed that the driving factors (contact time, stirring speed, solution pH, temperature, and initial concentration) greatly influenced improvement of the lead adsorption capacity, which reached 164.84 mg/g after 40 min of interaction. The adsorption isotherms demonstrated that the lead adsorption took place on a homogeneous surface and in a single layer, which was confirmed by the correlation coefficient and the ability of the Langmuir model to adsorb. The separation factor (R_L) and heterogeneity factor (1/n) demonstrated that adsorption was favorable, while the Temkin parameter (b_t) revealed that removal occurred through physical adsorption. According to the kinetic analysis, this process followed a pseudo-second-order kinetic model and was regulated by both external diffusion and intraparticle diffusion. Thermodynamic parameters demonstrated that lead adsorption was a spontaneous, exothermic, less entropic, and physical process, driven by electrostatic interaction. Activation energy revealed that the lead removal process occurred through physical adsorption. Desorption analysis demonstrated that SBM can be reused up to four consecutive times.

The epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2), pioneer members of the receptor tyrosine kinase subfamily, are frequently mutated and/or overexpressed in several types of human cancers, including nonsmall cell lung cancer (NSCLC) and breast cancer, which are leading causes of cancer-related deaths worldwide. EGFR and HER2-focused anti-NSCLC and antibreast cancer studies encouraged us to search for new potential agents. For this purpose, in the current work, naphthalene-linked pyrazoline-thiazole hybrids (BTT-1-10 and BTP-1-10) were synthesized and examined for their antiproliferative effects on A549 NSCLC and MCF-7 breast cancer cell lines. According to the results, the MTT assay showed that BTT-5 induced strong toxicity in A549 cells with an IC₅₀ value of 9.51 ± 3.35 μM compared to lapatinib (IC₅₀ = 16.44 ± 3.92 μM). BTT-5 also presented a high selectivity profile between the Jurkat cell line and PBMCs (healthy) (SI = 65.65). Furthermore, BTT-5 augmented apoptosis significantly in A549 cells (18.40%). BTT-5 displayed significant EGFR inhibition (58.32%) and no significant HER2 inhibition at 10 μM concentration, showing its selective kinase inhibitory effects. The molecular docking assessment indicated that BTT-5 showed high affinity with a different binding profile than lapatinib in the ATP binding cleft of EGFR. Consequently, BTT-5 can serve as a lead for future anti-NSCLC studies.

The detection of intracellular biothiols (cysteine, N-acetyl cysteine, and glutathione) with high selectivity and sensitivity is important to reveal biological functions. In this study, a 2-(2-methoxy-4-methylphenoxy)-3-chloro-5,8-dihydroxynaphthalene-1,4-dione (DDN-O) compound (3) was newly synthesized and used as a fluorogenic probe (detector molecule) in the fluorometric method for the rapid, highly selective, and sensitive determination of biothiols. The intensity values (λ_ex = 260 nm, λ_em = 620 nm) of the product were measured by adding biothiols to the reaction medium at varying concentrations and the glutathione equivalent thiol content values of each biothiol were calculated. Using compound 3, glutathione as the reference biothiol was detected in the linear concentration range of 10-70 μM and the LOD value was found to be 0.11 μM. Biothiol detection with structurally simple compound 3 was performed at the cellular level within 1 min and the probe was also successfully used in bioimaging with low cytotoxicity. It was concluded that this probe can serve as an alternative to existing fluorescence-based biothiol probes with applications in rapid biothiol detection at the cellular level for biological functions. To evaluate the molecular structure of 3, conformational analysis was performed using the PM3 semiempirical method. The most stable obtained molecular geometry was then optimized at the DFT/wb97xd/6-311++G(d,p) level of theory. Frontier molecular orbitals (HOMO and LUMO) and molecular electrostatic potential map analyses were performed for the optimized structure. Molecular docking studies demonstrated the interactions of 3 with HAS (1AO6) and FhGST (2FHE) target proteins.

A new nonperipheral zinc(II) phthalocyanine bearing octa carboxylic acid ethyl ester derivative substituted triazole attached propylmercaptothiobenzylmercapto derivative was synthesized via the tetramerization reaction of phthalonitrile. The photochemical in vitro photodynamic activity of zinc(II) phthalocyanine (ZnPc-I), such as human nonsmall cell lung carcinoma cell lines, was investigated in this study. The singlet oxygen generation property of novel zinc(II) phthalocyanine (ZnPc-I) was also examined due to the significantly high singlet oxygen quantum yield of ZnPc-I (F_D = 0.66). The antiproliferative effects of ZnPc-I were also investigated on the A549 and H1299 cell lines, and the results demonstrated that ZnPc-I had a strong antiproliferative effect on both cell lines.

The cocrystal (or supramolecular complex) between the Cu(II) complex of salicylic acid and uncoordinated piracetam has been synthesized. Its structure is characterized by elemental analysis, FT-IR, UV-Vis spectroscopy, and X-ray crystallography. Spectroscopic methods confirm the formation of the metal complex, while X-ray crystallography establishes the molecular and crystal structure of the obtained compound. The Cu(II) complex of salicylic acid (complex molecule) is a symmetric binuclear compound in the form of a "Chinese lantern" and contains 4 salicylic acid and 2 water molecules. It interacts with uncoordinated piracetam through a complicated system of hydrogen bonds. However, according to Hirshfeld surface analysis, the contribution of the O•••H/H•••O contacts is only 24.9%, while H•••H and H•••C/C•••H contacts account for 67.5%, indicating that intermolecular interactions are mainly hydrophobic. In silico (molecular docking) studies of the cocrystal, the complex molecule, and piracetam's antifungal, antibacterial, and antiviral activities confirm that the complex molecule demonstrates enhanced biological activities; practically, the inactive piracetam improved all tested types of bioactivities through cocrystal formation. For example, the binding energy in the case of anti-COVID activity is improved from -10.34 to -11.40 kcal/mol. Thus, cocrystal formation based on metal complexes and inactive organic compounds may be promising in drug design.

Cryogels containing isocyanate reactive groups were synthesized via photopolymerization of 2-isocyanoethyl methacrylate (ICEMA) and poly(ethylene glycol) methyl ether methacrylate (PEGMEMA). By changing the PEGMEMA and ICEMA ratios, cryogel series with varying ratios of reactive isocyanate groups were successfully prepared. The cryogels were characterized using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis, scanning electron microscope, and rheometry. To demonstrate that molecules containing amine groups can be immobilized onto synthesized cryogels through isocyanate-amine reactions, the cryogels were conjugated with 4-(trifluoromethyl)benzylamine (TFBA) and fluorescein amine (FLA) molecules, and the conjugations were confirmed through FTIR and fluorescence microscopy, respectively, for TFBA and FLA. Additionally, immobilization of fluorescein isothiocyanate conjugated albumin from bovine serum (FITC-BSA) as fluorescein-labeled model proteins was studied to illustrate that biomolecules can also be bound to the cryogels without any linker. It was shown that the amount of immobilized FITC-labeled model proteins can be controlled by adjusting the concentration of isocyanate reactive groups within the cryogel matrix, and this functionalization was confirmed by fluorescence microscope.

In this article, we describe the successful synthesis of three coordination compounds formed by the ligands 3-aminopyridine, 4-aminopyridine, and isothiocyanate ion with copper atoms and 4-aminopyridine and isothiocyanate ion with cadmium atoms, and their structural characterizations. The crystal structures of the compounds were determined by single crystal X-ray diffraction. According to that technique, the open formulae of these compounds are [Cu(3-aminopyridine)₂(NCS)₂] (1), [Cu(4-aminopyridine)₃(NCS)₂] (2), and [Cd(4-aminopyridine)₂(NCS)Cl] (3). In addition, the suitability of the structures of the compounds was characterized by elemental analysis, thermal analysis, and Fourier transform infrared spectroscopy. The single crystal X-ray diffraction analyses of these coordination compounds showed that the first of these coordination compounds had a 1D crystal structure and the other two had a 3D crystal structure. N-H⋯S, N-H⋯N, N-H⋯Cl, N-H⋯π, and C-H⋯π bonds and their combinations were effective in the formation of the crystal structures of the said coordination compounds. The metal atoms [Cu(II), Cu(II), and Cd(II)] in these coordination compounds were surrounded by various ligand molecules in a square planar, square pyramidal, and octahedral arrangement, respectively. In order to investigate some chemical and structural properties of these coordination compounds, theoretical calculations were performed with the software package Gaussian 03. The highest occupied molecular orbital (HOMO), lowest occupied molecular orbital (LUMO), and natural bond orbital (NBO) values of the coordination compounds were used in these calculations. When the energy gap value between the HOMO and LUMO states of the compounds was examined, it was predicted that compound 3 may have lower kinetic stability, higher chemical activity, and lower semiconductor properties than all the other compounds. According to the Hirshfeld surface analysis of the compounds, C⋯H, S⋯H, H⋯H, and N⋯H interactions are generally seen in the crystal structures of all compounds. In addition, Cd⋯Cl, Cd⋯S, H⋯Cl, and Cl⋯Cl interactions also occur in compound 3.

[This corrects the article on p. 332 in vol. 40.].