Turkish Journal of Chemistry最新文献

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.

The rise in the popularity of electric vehicles and portable devices has boosted the demand for rechargeable batteries, with lithium-ion (Li-ion) batteries favored for their superior energy and power density. However, supply strains and sustainability issues are driving the search for alternatives. Postlithium technologies, particularly sodium-ion (Na-ion) batteries, are gaining attention for their promising potential and similarity to Li-ion technology. While efforts are still needed to enhance the energy and power density as well as the cycle life of Na-ion batteries to replace Li-ion batteries, these energy storage devices present significant advantages in terms of sustainability, theoretical capacity, and intrinsic safety features. Through this paper, the current state of Na-ion batteries, focusing on key components such as anodes, electrolytes, cathodes, binders, separators, and current collectors, has been critically assessed. Recent advancements, challenges, future directions, and new materials engineering strategies for improving electrochemical performance are also discussed. Overall, this review offers a comprehensive analysis of the development of high-performance, cost-effective, and sustainable energy storage systems.

In whole-rock geochemical analysis, the quantification of aluminum in geological samples is performed using different analytical techniques including UV-Vis spectrophotometry. During the spectrophotometric analysis of aluminum utilizing Alizarin Red S, iron causes significant interference, leading to inaccurate measurements of the amount of aluminum in the sample. In cases where leached or processed samples contain titanium, interference is also observed. However, appropriate masking agents can remove these interferences. In this study, various masking agents including Tiron, oxalic acid, ascorbic acid, and thioglycolic acid were utilized for the masking of iron. Among these masking agents, ascorbic acid proved to be the best candidate for masking iron. A simple and efficient method was then developed for the masking of iron with the optimization of parameters including concentration of ascorbic acid and reaction time. With this technique, 2 mL of ascorbic acid (10%) can mask iron at up to 3000 ppm in aliquots. Moreover, titanium interference is not observed with this method when the titanium concentration in the aliquot is below 100 ppm. This method was subsequently applied to geological samples and the results were compared to those of atomic absorption spectroscopy. Most samples can easily be analyzed for aluminum by utilizing this masking technique and circumventing interference problems.

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

Structural modifications in lichen phenolic compounds have been one of the tools to potentiate their biological activity. In the present work, seven alkyl derivatives of norstictic acid were prepared and evaluated against eight cell lines. Norstictic acid was isolated from the lichen Ramalina anceps and the alkyl derivatives were obtained through reactions with alcohols. Cytotoxicity was evaluated against the 786-0 (kidney carcinoma), MCF7 (breast carcinoma), HT-29 (colon carcinoma), PC-03 (prostate carcinoma), HEP2 (laryngeal carcinoma), B16-F10 (murine melanoma), UACC-62 (human melanoma), and NIH/3T3 (mouse embryonic fibroblast) cell lines using the sulforhodamine B assay. Norstictic acid exhibited poor activity, while the 8'-O-n-butyl-norstictic acid and 8'-O-sec-butyl-norstictic acid derivatives showed potential activity (GI₅₀ values of 6.37-45.0 μM and 6.8-52.40 μM, respectively) and high selectivity (selectivity index (SI) values of 13.88-98.11 and SI 11.30-87.40, respectively) against all tumor cells. The 8'-O-n-hexyl-norstictic acid showed good activity (5.96-9.53 μM) and moderate selectivity (SI 9.2-5.76) against MCF7, HT-29, PC-03, and HEP2 cells, while 8'-O-isopropyl-norstictic acid demonstrated high activity and selectivity against PC-03 cells (GI₅₀ 1.28 μM and SI 33.8), and was highly active but moderately selective against UACC, HEP2, and B16-F10 cells (GI₅₀ 6.2, 7.78, and 9.65 μM; SI 7.0, 5.5, and 4.5, respectively). Additionally, 8'-O-n-pentyl- and 8'-O-tert-butyl-norstictic acids were active and selective against PC-03 cells (GI₅₀ 8.77 and 7.60 μM; SI 6.53 and 5.0, respectively). Chemometric analysis revealed a clear relationship between all compounds and their biological activities. The insertion of a four-carbon alkyl chain (n-butyl and sec-butyl) produced potentially active compounds on all tested tumor cells.

The adsorption of glacial acetic acid over a charcoal support was investigated. The amount of adsorption was analyzed using a traditional titration method and the prepared adsorbed system was employed as a heterogeneous catalyst for organic reactions as a viable application. Different 14-aryl-14H-dibenzo[a,j]xanthenes were synthesized using mild acidic charcoal as a catalyst and yields of 88%-94% were obtained. The advantages of this method include the easy preparation of a cheaper and environmentally safe catalyst system, a simple work-up procedure, and excellent catalytic efficacy.

Inflammation is a response to injury and infection in an organism. It can be categorized as acute or chronic. Chronic inflammation is the underlying cause of many diseases such as Alzheimer disease, diabetes, rheumatoid arthritis, atherosclerosis, and cardiovascular diseases. Recent studies have proven the antiinflammatory properties of 1,4-dihydropyridines (1,4-DHPs) and their derivatives, which have many biological activities including the blocking of calcium channels. In this study, 15 compounds that are condensed derivatives of 1,4-DHPs, with the general structure of hexahydroquinoline-3-carboxylate, were synthesized. These compounds, expected to show inhibitory activity against inflammatory mediators, were obtained by the reaction of 4-(difluoromethoxy)benzaldehyde, substituted/nonsubstituted 1,3-cyclohexanedione derivatives, and appropriate alkyl acetoacetate compounds in the presence of ammonium acetate as a nitrogen source according to the Hantzsch synthesis method. The structures of the synthesized compounds were elucidated by IR, ¹H NMR, ¹³C NMR, and HRMS methods. The cytotoxic properties of the compounds were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method in the 3T3 cell line. Among the 15 compounds, the three compounds with the lowest levels of cytotoxic effects were selected for further experiments. Inflammation was induced by lipoxygenase and the effects of the selected compounds on the levels of reactive oxygen species, cytokines, and complement C3 and C9 regulatory proteins were investigated. It was found that the three selected compounds decreased the levels of transforming growth factor-beta 1 (TGF-β1). Among these compounds, compound 3e provided the most significant decrease in this cytokine. Moreover, 3e increased both C3 and C9 levels. Molecular modeling studies also showed that 3e had better affinity for TGF-β1. When the binding modes of these compounds in the active site of TGF-β1 were analyzed, it was found that compound 3e had hydrophobic interactions with amino acids Leu142, Tyr84, and Ile13; halogen bond interactions with Asp92; and hydrogen bond interactions with Ser89, Gly88, and Gly14 in the active binding site. Further in vitro and in vivo studies are needed to show the possible mechanism of action of compound 3e.

A novel electrochemical nanogenosensor devoted to clinical analysis is reported for label-free detection of pathogenic microorganisms in the present work. The designed biosensor is composed of graphene oxide-modified disposable pencil graphite electrodes as a sensing platform. Escherichia coli is used as a model case. A 5'-aminohexyl-linked 22-base sequence probe representing the E. coli amplicon is immobilized onto sensor surfaces via carbodiimide chemistry. Hybridization is performed with denatured PCR amplicons of the bacteria. Detection is realized by transduction with the electrochemical impedance spectrometry technique. The selectivity of the designed genosensor is measured using Mycobacterium tuberculosis and Klebsiella pneumoniae sequences. Outstanding sensitivity is achieved with this genosensor array platform with a detection limit of 102 nM. This platform offers promise for rapid, simple, and cost-effective detection of various pathogenic microorganisms.

A novel Fe₃O₄@coPPy-PTH nanocomposite-based sorbent was prepared via in situ oxidative polymerization using Fe₃O₄ nanoparticles with spherical and flower-like morphologies of thiophene and pyrrole as the feedstocks. The synthesized nanocomposite displayed sensitive extraction and determination of metal ions Co(II), Cr(III), and Ni(II) without a chelating agent, followed by microsample injection system-flame atomic absorption spectrometry. Advanced spectroscopic and imaging techniques including scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy were used to characterize the composition and morphology of the Fe₃O₄@coPPy-PTH nanocomposite. SEM observations showed that the size of the Fe₃O₄ nanoparticles changed from 30 nm to 120 nm in diameter after copolymer (PPy-PTH) coating. The Fe₃O₄@coPPy-PTH nanocomposite has good dispersion properties and stability in strong acid solutions. For effective extraction of the studied analytes, the influence of sample pH, volume of sample solution and eluent, amount of adsorbent, and interference of coexisting metal ions were optimized. Under the optimum conditions, preconcentration factors were obtained as 25 for all analytes. The calibration curves were linear in the range of 0.0-10.0 μg L^-1 with coefficients of determination (R²) greater than 0.9957 for all three analytes. Limits of detection (S/N = 3) were calculated in the range of 0.17-0.23 μg L^-1. Precision values, expressed as relative standard deviations, were lower than 3.0%, and relative recoveries were obtained in the range of 88.6%-103.6%. The proposed method (Fe₃O₄@coPPy-PTH/MSPE/MIS-FAAS) was successfully applied to extract and determine the studied metal ions in beer, wine, and nonalcoholic beverage samples.

The analysis of substances and samples obtained from a crime scene is very important in solving forensic cases. To determine the variables involved in a crime and to expedite the investigation process, the rapid analysis of body fluids in small quantities and within environments containing diverse components is particularly necessary. For this reason, it is of great importance to analyze biological fluids with rapid, noncontaminating, nondestructive, low-cost, and accurate techniques. In recent years, with advancements in laser technology, spectroscopic methods have been introduced as analytical techniques in forensic medicine and chemical studies. This study focuses on surface-enhanced Raman spectroscopy (SERS) to demonstrate the detection of blood samples in simulated crime scenes. To minimize the background signal from fluorescent biomolecules in blood, dilution was performed with two different components and Raman analysis was performed for four different concentrations of blood. In general, a decrease in noise in the spectra was observed as the blood was diluted. Crime scenes consisting of pure blood, blood diluted with ethanol and distilled water (1:2, 1:4, and 1:8), a blood-mineral water mixture, a blood-cherry juice mixture, and silver nanoparticle-added mixtures were simulated, and their spectra were examined. Chemometric analyses of the data were performed. Despite high noise and low peak intensities, blood-identifying signals were detected when examining different blood concentrations. It was observed that silver nanoparticles provided high enhancement of blood peaks thanks to their strong plasmonic properties.