Chemical Review and Letters

Abstract Since bioethanol is produced as a green fuel in an aqueous solution, improving the process of separating of ethanol/ water mixture is crucial due to the presence of an azeotropic point in the distillation process. Therefore, ethanol separation processes, conducted concurrently with its production in bioreactors, with an emphasis on membrane-based processes and focusing on pervaporation, are preferred due to their lower cost and energy requirements for ethanol separation. In this study, the design and construction of a pervaporation unit were first carried out. Then, the ethanol-water separation process was modeled using the Solution-Diffusion model and the Flory-Huggins theory in pervaporation. The dense polydimethylsiloxane (PDMS) membrane was used due to its superior selectivity for ethanol. The results showed that ethanol could be separated from water at any feed composition without any azeotropic point. Furthermore, by calculating the diffusion coefficients of ethanol and water from the model and ultimately determining the partial ethanol and water fluxes, it was observed that the calculated flux values from the model closely matched the experimental flux values for each component. Additionally, increasing the ethanol concentration in the feed led to an increase in ethanol’s diffusion coefficient, a decrease in water’s diffusion coefficient, an increase in total flux, and ultimately a reduction in the separation factor, which were in good agreement with the experimental selectivity values obtained from the experiments. This indicates the validity of using the Flory-Huggins model for predicting ethanol separation from water in the pervaporation process.

Abstract In this article provides detailed information on the synthesis of polyfunctional immobilized ligands that form a complex with nitrogen and oxygen, the preparation of complex compounds of some d-metals based on them by the sorption method, and the composition, structure, and properties of the obtained compounds. in determining the structure and other physico-chemical properties of complex-forming polyfunctional immobilized ligands, based on the results of RTT, IR-spectroscopy, modern quantum-chemical calculations, the individuality of newly synthesized complex compounds and the coordination of immobilized ligands containing nitrogen and oxygen atoms with d-metals were determined. In addition, the static and dynamic exchange capacities of the synthesized immobilized ligands with respect to Cu(II), Zn(II), Ni(II), Cd(II), Ag(I) and other 3d-metal ions were determined, and the selective binding of ligands to metals was determined. There is a lot of information about the composition of the sensitivity series.

Abstract In the work, a new mixed metal chloride complexes of palladium (II), platinum (IV) and gold (III) were prepared by the metal condensation reaction with amoxicillin as a primary ligand (L) with 2-(4,5-di(4-methoxyphenyl)-2-(4-(methylthio)phenyl)-1H-imidazole-1-yl)-5-methylphenoln as secondary ligand (L/).The compounds' structural were characterized by the application of analytical and spectroscopic methodologies. The results of the research showed that the coordination sites of the ligands with the metal ions were diastereomers due to amoxicillin's (L) two oxygen atoms, and in contrast, derivative imidazole(L/) using sulfur and oxygen atoms. The Pt (IV) complex was shown to have an octahedral structure through spectroscopic and analytical studies, whereas the Pd(II) and Au(III) complexes exhibited square planar structures. The ligands and the new compounds were evaluated against strains of bacteria and fungi (E.coli as Gram(-), Staphy. as Gram(+), and Cand.) at three different concentrations (50, 100, and 200) ppm. The results showed that the Au (III) complex was more effective than other compounds. Furthermore, based on the outcomes of the cytotoxic assay, the newly formed complexes were efficiently screened to examine their toxicity as an anticancer drug against MDA cell lines. Specially at high concentrations, these synthetic compounds offer potential as novel candidates for anticancer drugs in the future.

Abstract Distinguishing the electronic differences between epoxy- and hydroxyl-functionalized graphene is essential, as each group alters the charge distribution and electronic density. These changes affect K⁺ ion interactions, including adsorption strength and selectivity. The Density Functional Tight Binding (DFTB) method effectively captures these differences and reveals their distinct interaction mechanisms. Both the epoxy and hydroxyl groups significantly modify the electronic properties of graphene, notably increasing the electronic density near the Fermi level. A band gap of 0.72 eV was observed in hydroxyl-functionalized graphene (GH), likely resulting from changes in the delocalized orbitals between the HOMO and LUMO. In contrast, epoxy-functionalized graphene (GE) exhibited no significant band gap opening or Fermi level shift, indicating a more conductive structure. The charge density differences further reveal distinct charge accumulation and distribution patterns on the GE and GH surfaces, consistent with their respective density of states (DOS) spectra. This variation in electronic structure directly influences their interaction with K⁺ ions, with measured interaction energies of –1.702 eV for GE and –1.423 eV for GH, suggesting that GE provides a more favorable environment for K⁺ ion support.

Abstract Phenacyl bromides have long served as important building blocks in chemical synthesis, particularly in the preparation of heterocyclic compounds owing to their two contiguous electrophilic centers. Consequently, tremendous efforts have been devoted to the development of efficient synthetic methodologies to this specific class of carbonyl compounds. The direct vicinal oxybromination of widely available styrene derivatives is one of the most efficient procedure for preparation of the titled compounds, benefiting high step, atom and pot economy. In this Mini-Review we discuss some of the most representative and interesting recent reports on the synthesis of phenacyl bromides through the direct oxybromination of respective styrenes with an emphasis on the reaction mechanisms.

Abstract Thiazole derivatives, a type of heterocyclic compounds, have gained significant attention in the field of medicinal chemistry due to their diverse pharmacological activities. They play a crucial role in the pharmaceutical industry because of their unique properties. This review aims to thoroughly examine the existing literature on thiazole derivatives, specifically focusing on their antioxidant and antimicrobial activities. Recent research has mainly concentrated on investigating the antioxidant properties of these derivatives. The review systematically explores numerous studies that have looked into the radical-scavenging abilities and modulation of enzymatic antioxidant defenses exhibited by thiazole derivatives. Additionally, it conducts a comprehensive analysis of the impact of structural modifications on the effectiveness of antioxidants. In terms of antimicrobial activity, thiazole derivatives have shown significant efficacy against a wide range of microorganisms.

Abstract In this research, Nd2CuFe2O7 (NCuFO) nanoparticles were synthesized through the coprecipitation method and identified by energy dispersive X-ray (EDX), elemental distribution map, field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) analyses. Polyaniline (PANI) and chitosan (CHS) were used as effective and suitable substrates for nanoparticles. A novel Pt-NCuFO/PANI-CHS nanocatalyst was prepared by chemical reduction of hexachloroplatinic acid in the presence of NCuFO nanoparticles on the PANI-CHS substrate. The nanoparticles' distribution on the substrate was shown by TEM images. The catalytic performance of the Pt-NCuFO/PANI-CHS for methanol electro-oxidation was evaluated, compared to Pt/PANI-CHS. The effects of several experimental factors for methanol electro-oxidation were investigated. Pt-NCuFO/PANI-CHS catalyst showed better antipoisoning effect, higher electrochemically active surface area, and better stability towards methanol oxidation than Pt/PANI-CHS catalyst. The improved catalytic performance of Pt-NCuFO/PANI-CHS, compared to Pt/PANI-CHS suggests its promising application in direct methanol fuel cells.

Abstract This study investigates the effect of chitosan content on the synthesis, physicochemical properties, and adsorption performance of activated carbon/chitosan composites for the removal of Rhodamine B (RhB) dye from aqueous solution. This study aims to determine the characteristics, including functional groups, moisture content, and stability of activated carbon/chitosan composites, as well as to obtain data on the ability of activated carbon/chitosan composites in adsorbing RhB. Activated carbon/chitosan composites were prepared with varying weight ratios of activated carbon to chitosan (8:2, 8:4, 8:6, and 8:8) and characterized using Fourier-Transform Infrared (FTIR) spectroscopy, UV-Vis spectrophotometer, and Scanning Electron Microscope (SEM). FTIR results confirmed the successful incorporation of chitosan onto the activated carbon matrix through hydrogen bonding and functional group interactions. Increasing chitosan content enhanced the presence of polar groups but led to decreased surface area and pore accessibility. The adsorption studies revealed that the composites achieved equilibrium within 60 minutes, with maximum adsorption observed at neutral pH. Adsorption data were best fitted by the Langmuir isotherm model, with maximum adsorption capacities of 71.41, 49.01, 41.84, and 37.59 mg/g for composites with increasing chitosan content, respectively. The data shows that while chitosan introduces functional sites favorable for dye interaction, excessive loading may hinder adsorption due to pore blockage.

Abstract This study seeks to develop and validate two straightforward, sensitive, accurate, and cost-effective spectrophotometric techniques for detecting bromocriptine mesylate, an anti-parkinsonian medication, in its pure form and in pharmaceutical formulations. The methods rely on establishing a charge transfer complex between bromocriptine mesylate as the n-donor and either quinalizarin (Quinz) and alizarin red S (ARS) as π-acceptors in methanol. This results in the formation of highly colored chromogens with absorption maxima at 551 and 521 for Quinz and ARS, respectively. The study examined the optimization of reaction parameters. The stoichiometric ratio of the produced charge transfer complexes was determined to be 1:1 (bromocriptine mesylate:reagent) using Job's method of continuous variation for both approaches. Beer’s law was followed within the concentration ranges of 1.0–20 and 1.0–24 μg mL⁻¹ using Quinz and ARS, respectively, under optimum circumstances. This assertion is supported by a significant correlation coefficient (r² > 0.9992) and a low relative standard deviation (RSD% < 0.84). The detection and quantification limits were set at 0.30 and 1.0 μg mL-1 for both reagents. The proposed approaches were effectively utilized to quantify bromocriptine mesylate in pure form and pharmaceutical formulations, and the validity was assessed using the standard addition technique.

Abstract The complexation of Cu(II) with dimercaptophenols (2,6-dimercapto-4-isopropylphenol and 2,6-dimercapto-4-sec-butylphenol) and hydrophobic amines has been investigated by instrumental methods. Heterocyclic diamines such as 1,10-phenanthroline, 2,2'-dipyridyl and 4,7-diphenyl-1,10-phenanthroline (bathophenanthroline) were used as hydrophobic amine. The optimal conditions for the formation and extraction of mixed-ligand compounds were found and the ratios of components in the complexes were established. Spectrophotometric techniques for the determination of Cu(II) in various objects have been developed. The proposed methods are characterized by good reproducibility and low detection limits.

Abstract This review gives an overview of recent findings and developments in research on direct iodofluorination of alkenes. The review is divided into two major sections according to iodofluorinating reagents. The first includes the iodofluorination of alkenes using bifunctional reagents, while the second contains the three-component reactions.

Abstract This study focuses on innovative water treatment solutions by investigating the photocatalytic degradation of Congo red dye using two advanced nanomaterials, thin films of zinc oxide (ZnO) and zinc manganese oxide (ZnMn2O4). Both nanomaterials were derived from nitrate precursors at calcination temperatures of 500, 650 and 800 ˚C. Detailed synthesis protocols were meticulously designed to enhance the structural and morphological properties of the photocatalysts, which aims to maximize their photocatalytic efficiency under UV light irradiation. The characterization was carried out using X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), fourier-transform infrared spectroscopy (FT/IR), UV-Visible spectroscopy, diffuse reflectance spectra (DRS) and field emission scanning electron microscopy (FE/SEM). The thin films were prepared using the Doctor Blade technique. The particle size of the nanomaterials used in thin-film fabrication was calculated using the Scherrer equation, yielding values between 22 and 32 nm. Optical studies revealed that ZnMn2O₄ possesses a narrower band gap, ranging from 2.47 to 4.06 eV, compared to ZnO’s band gap of 3.36 eV. This narrower band gap enhances light absorption and improves charge separation both key factors for effective photocatalysis. Comparative photocatalytic experiments revealed that ZnMn2O4 exhibits superior performance over ZnO in degrading Congo red dye, achieving higher degradation efficiency (85.3%) and faster reaction kinetics (0.0138 min-1), compared to ZnO’s respective values of 70% and 0.0081 min-1. The superior performance of ZnMn2O4 is attributed to its optimized electronic structure and increased surface area, which results in a smaller particle sizes and more porous morphology. These findings highlight the potential of ZnMn2O4 nanocomposites as promising candidates for sustainable and efficient water treatment applications.

Abstract The study investigated the fabrication of NiCoCrAlY intermediate coatings on Inconel 718LC nickel-based superalloy substrates using electrochemical deposition from a Watts bath containing NiCrAlY particles, followed by homogenization treatment. To achieve an optimal particle size, the initial NiCrAlY powder was mechanically milled under an argon atmosphere for 30 hours. The effects of NiCrAlY powder concentration in the electrodeposition bath and current density on the incorporation of co-deposited NiCrAlY particles and coating microstructure were examined. After deposition, the coatings were homogenized at 1100°C for 2 hours in an argon environment to ensure chemical uniformity. The chemical composition, phase structure, morphology, and hardness of the coatings were characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and Microhardness testing. Results revealed that low powder concentrations and current densities resulted in limited incorporation of NiCrAlY particles, while increasing these parameters initially enhanced particle incorporation before eventual decline. Homogenization promoted the formation of γ'(Al3Ni) intermetallic phases within the γ (Ni, Co) matrix. The increased incorporation of co-deposited particles improved hardness through solid solution strengthening, γ'(Al3Ni) intermetallic phase formation, and microstructural refinement. The coating deposited at an optimal current density of 20 mA/cm2 and NiCrAlY powder concentration of 20 g/l exhibited the highest hardness.

Abstract This study explores the development and characterization of polymeric scaffolds containing sodium alginate microspheres loaded with methotrexate for controlled drug delivery. We fabricated scaffolds using hexamethylene diisocyanate and polyelectrolyte, incorporating drug-loaded microspheres, scaffolds were thoroughly characterized using various analytical techniques, including FTIR, XRD and SEM, drug release kinetics were evaluated under physiological conditions, demonstrating sustained release profiles over 150 hours, examinations of void spaces unveiled highly permeable structures conducive to cellular penetration and nutrient circulation. Decomposition patterns were evaluated in oxidizing and enzymatic settings, demonstrating steady disintegration across multiple weeks. Our discoveries indicate that these frameworks show potential for utilization in pharmaceutical administration and biological tissue construction, providing adjustable characteristics and regulated discharge abilities.

Abstract This review aims to summarize the current literature on the direct vicinal cyano-acylation and cyano-esterification of unsaturated hydrocarbons, with a particular focus on the mechanistic features of these reactions. This review is structured into four main sections. The first section covers the cyano-acylation of alkenes, followed by a discussion of cyano-esterification of alkenes in the second section. The third section consists of an overview of cyano-acylation of alkynes, while the final section focuses on the cyano-esterification of alkynes.

Abstract Methylxanthine-derived theophylline is a well-known bronchodilator medication with additional anti-inflammatory and immunomodulatory properties theophylline is mixed with thiourea and aldehydes in ethanol to form the new compounds, which are subsequently synthesized by 4-bromophencylbromide closing the ring. Utilizing thin-layer chromatography, to assess the products' purity by TLC. Melting point measurements, FT-IR spectroscopy, H-NMR, C13-NMR, for final compounds, have all been used to characterize and confirm the chemical composition of intermediate and terminal compounds. The initial investigation of antibacterial activity, which involved five distinct bacterial strains, revealed that