Monatshefte für Chemie / Chemical Monthly最新文献

A sensitive and selective electrochemical method for the determination of kanamycin was established first at the surface of a pencil graphite-embedded PTFE cannula electrode according to the analysis mechanism of target-induced spatial configuration of aptamer-complementary strand hybridization. The electrochemical characteristics studies of homemade electrodes were using cyclic voltammetry. The result showed that the PFTE nested pencil graphite electrode with polished and gold deposits has good electrode application potential. The electrochemical analysis method for kanamycin was performed using differential pulse voltammetric techniques. Modification of the homemade electrode surface increased its DPV response of methylene blue in the presence of kanamycin because more analytes affected the aptamer-complementary strand hybridization conformation. Thus, more G-quadruplexes formed to capture methylene blue. The developed electrochemical sensor yielded a positive correlation between the electrochemical signal and the logarithmic concentration of kanamycin with a wide linear range (15.3 nM to 0.24 mM) and a low limit of detection of 10 nM. The developed sensor was assessed by the analysis of kanamycin in wastewater treatment plant effluent samples by spiked recovery method. The analysis results (recoveries range of 97.5–105% and RSD range of 2.1–7.8%, respectively) proved that the method performance was both acceptable and admirable.

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Ring expansion of 4-[(2R)-1-[(1R)-1-phenylethyl]aziridin-2-yl]butyl tosylate obtained from tosylation of 4-[(2R)-1-[(1R)-1-phenylethyl]aziridin-2-yl]butan-1-ol via formation of 1-azabicyclo[4.1.0]heptane tosylate gives substituted piperidine. The ring openings of azabicycloheptane tosylate with acetate nucleophiles proceeded in highly regio- and stereoselective manner with release of the ring-strain of the three-membered aziridine ring through the breakage of either C-N bond. This ring expansion streategy of aziridine provides a short route for asymmetric synthesis of biologically active natural alkaloid such as (R)-pipecolic acid.

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This study presents the development and validation of a novel capillary zone electrophoresis method for the precise determination of glatiramer acetate and its amino acid constituents. A 120 mmol dm⁻³ phosphoric acid solution adjusted to pH 1.9 with Tris, supplemented with 20 mmol dm⁻³ triethylamine to achieve a final of pH 2.1, resulted in a repeatable analysis of glatiramer acetate. The method demonstrated a limit of detection and quantification of 39.2 µg cm⁻³ and 130.7 µg cm⁻³, respectively. This method allows for the rapid control of glatiramer acetate-based pharmaceuticals and distinguishes glatiramer acetate from the amino acids used in its synthesis.

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The electrochemical behavior in nonaqueous media of a series of five newly synthesized azo-stilbene dyes is investigated with the aim of elucidating the anodic oxidation mechanism of the latter to gain a better understanding of potential oxidative degradation phenomena to find new and environmentally sustainable electrochemical methods for the abatement of dyes from industrial wastewater. In addition, the frontier orbital energies of optimized conformers have been computed using quantum chemical calculations at the B3LYP-D3 (dispersion corrected Becke, 3-parameter, Lee Yang Parr) level of theory. Cyclic voltammetry experiments show that anodic oxidation of the studied chromophore structures follows an irreversible pathway and most probably occurs at the amide nitrogen. Validation of experimental results has been conducted by computation of various global reactivity descriptors, confirming that substituents grafted on the benzene ring actively influence the oxidation/reduction potentials.

This paper briefly discusses electronegativity and uses of the electronegativity scale. It demonstrates that values of electronegativity can be used quantitatively in simple equations. Formulas containing derived values of elemental electronegativities are shown to calculate dipole moments, bond lengths, and bond energies reliably. Comparison between calculated and experimental values shows very good agreement in the vast majority of cases.

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Our contribution discusses the possibility of using spray drying synthesis for the preparation of active cathode material for Li-ion batteries. The particles were synthesized using a two-stage spray drying synthesis of NMC material (Li_1.2Ni_0.13Mn_0.54Co_0.13O₂), when we separated the processes of synthesizing the nanoparticles (step 1) themselves and the subsequent calcination were separated from each other. Synthesis was based on spraying of precursor solution via ultrasonic atomizer and dried particles were captured using an electrostatic separator. During the following calcination step, the effect of temperature on the crystallization of the sample was investigated in the temperature range of 400–900 ℃. The temperature of 750 ℃ proved to be ideal for sufficient formation of a crystalline structure while maintaining a sufficiently fine-grained structure. At this temperature, the influence of the length of calcination was also investigated for the following times: 2.5, 5, 10, and 20 h. The structural and morphologic characterization of synthesized material was examined with X-ray diffraction and scanning electron microscopy with energy dispersive spectroscopy.

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In this innovative approach, a methodology was formulated to simplify the electrochemical analysis of the specified anti-inflammatory and analgesic drug, brucine (BCN), in 0.2 M phosphate buffer solution (PBS) by preparing an affordable, easy to use, and eco-friendly carbon nanotube paste electrode (CNTPE). This method was created using an electrode treated with glutamic acid (GL) through electrochemical polymerization along with a bare carbon nanotube paste electrode (BCNTPE) using pH 7 for different cycles (5, 10, 15, 20), with ten cycles revealing the optimum peak. This study presents an innovative electrochemical sensor employing a polymerized glutamic acid (GL) modified carbon nanotube paste electrode (P-GL(MCNTPE)). The sensor is specifically designed to detect BCN with high sensitivity and selectivity. The prepared electrodes, namely P-GL(MCNTPE) and BCNTPE, are utilized for comprehensive material and system characterization using various electrochemical techniques, including cyclic voltammetry (CV), differential pulse voltammetry (DPV), scanning electron microscopy (SEM), and electrochemical impedance spectroscopy (EIS). The developed sensor noticeably enhanced the electrochemical activity of BCN when placed in a pH of 4.0 PBS (0.2 M). BCN undergoes a distinctive two-proton and two-electron transfer process. Scan rate studies reveal that the electrode surface behaviour is largely governed by diffusion control. By varying the BCN concentration at pH of 4.0 in a scan rate of 0.1 V/s using DPV technique, the lower limit of detection was found to be 1.5 × 10^–8 M, and the lower limit of quantification was determined to be 5 × 10^–8 M. These measurements were obtained as the BCN concentration varied from 0.2 to 1.2 µM. The developed electrode maintains good sensitivity for detecting BCN, despite the presence of potential interferents like organic compounds and metal ions. This sensor is stable, repeatable, and reproducible in oxidizing BCN. Real sample (tablets) analysis was done using DPV method demonstrates a favorable recovery rate.

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The current report provides an overview of the rapidly developing class of pyrazolines having a benzothiazole moiety at N¹. The synthetic approaches (mainly through the [3 + 2] cyclo-condensation of chalcone analogs with 2-hydrazinobenzothiazole) toward these particular pyrazolines, along with their chemical transformation to pyrazoles through oxidation are outlined. The photophysical properties (absorption and emission spectra) along with their applications as fluorescent chemosensors have been summarized. 1-(2-Benzothiazolyl)pyrazolines exhibit significant fluorescence quenching mostly in the presence of transition metal ions, such as Fe³⁺, Cu²⁺, Hg²⁺, Zn²⁺, or Ni²⁺, but also toward Al³⁺, thus enabling the selective detection of these analytes. In addition, examples of 1-(2-benzothiazolyl)pyrazolines acting as chemosensors for anions such as S²⁻ or F⁻ are also available. Comprehensive examination of the biological properties of 1-(2-benzothiazolyl)pyrazolines shows that members of this class possess either broad or selective significant antimicrobial activity, along with tuberculostatic activity and cytotoxicity that is sometimes better than that of positive controls. The antidiabetic, anti-inflammatory, anthelmintic, and antimalarial activity of these compounds, along with their potential for inhibition of enzymes such as carbonic anhydrase or acetylcholinesterase have been briefly explored.

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This study is dedicated to the acquisition and quantification of processing parameters essential for the fabrication of customizable organic–inorganic hybrid nano/microfibers through electrospinning. These fibers are generated from suspensions comprising active electrode materials utilized in the construction of all solid-state batteries. Owing to the catalytic properties exhibited by certain electroactive materials and the coagulation tendencies stemming from the presence of various particles, there exists a limited operational interval within which stable fibers can be produced while maintaining the suspension at a suitable viscosity. Our second goal was to ascertain the relationship between the quality of the resulting fibers and the spinnability of the suspension, particularly regarding its electrical conductivity. Solutions and suspensions were studied with help of ²⁹Si NMR spectroscopy, EIS, and conductometry, fiber morphology with confocal and electron microscopy.

Due to characteristic properties of ionic liquids such as non-volatility, high thermal stability, negligible vapor pressure, and high ionic conductivity, ionic liquids-based electrolytes have been widely used as a potential candidate for renewable energy storage devices, like lithium-ion batteries and supercapacitors and they can improve the green credentials and performance of energy storage devices. Furthermore, ionic liquids have found extensive use in solar cells as electrolytes, demonstrating favorable outcomes in terms of increased durability and heightened efficiency of the devices. These devices have become indispensable in human life and they are playing a vital and promising role in the worldwide endeavor to address both the challenges of renewable energy supply and air pollution simultaneously. The energy storage ability and safety of energy storage devices are in fact determined by the arrangement of ions and electrons between the electrode and the electrolyte. In this review, we provide an overview of ionic liquids as electrolytes in lithium-ion batteries, supercapacitors and, solar cells.

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