A new coordination compound [Zn(bpy)(L)]2·6H2O was synthesized by 2,2'-bipyridine (bpy), 3-carboxy-1-carboxymethyl-2-oxidopyridinium (H2L) and Zn(II) as starting materials under solvothermal conditions. Single-crystal X-ray diffraction shows that the compound is ultimately assembled from a one-dimensional chain structure into a three-dimensional supramolecular framework via π-π interactions and hydrogen bonds. Meanwhile, infrared spectroscopy was employed to verify the successful synthesis of the compound. In addition, the hydrogen bonds and other intermolecular interactions within the compound were further investigated by Hirshfeld surface analysis.
Electrospun indium tin oxide (ITO) structures face challenges with high-temperature calcination, dopant homogeneity, and reduced electrical conductivity due to porosity and grain boundaries. However, ongoing advances in precursor design and post-treatment strategies afford promising routes to improve performance and scalability regarding optoelectronic applications. In this study, ITO was synthesized via electrospinning followed by post-annealing, and its morphological, structural, and optical properties were evaluated to assess its suitability as a transparent conductor. The fibers were produced by electrospinning using a precursor solution containing indium trichloride (InCl3), tin chloride dihydrate (SnCl2∙2H2O), and polyvinylpyrrolidone (PVP). The resulting electrospun mat exhibited an average fiber diameter of 0.56 μm. Following post-annealing of the resulted fiber mat at 700°C, ITO with a cubic bixbyite-type structure and an average particle size of 2.06 μm was obtained. The EDS spectrum shows only indium, tin, and oxygen, indicating as the principal constituent elements of the synthesized ITO. DRS results indicate that post-annealing decreases %Rmax from ~ 50% to 28%, reflecting the transition from porous, highly scattering mat to crystalline ITO. This work demonstrates that electrospinning followed by post-annealing could produce crystalline ITO particles, offering a promising alternative to conventional high-temperature solid-state processing.
A series of compounds having a benzoxazole moiety in their structure have been synthesized starting from 6-hydroxy-2-methylbenzo[d]oxazole, whose preparation through the Beckmann rearrangement of resacetophenone oxime is described. First, substitution with bromine and chlorine of the aforementioned heterocyclic phenol using molecular bromine and N-chlorosuccinimide was shown to lead to the corresponding 5,7-dibromo-6-hydroxybenzo[d]oxazole and 5,7-dichloro-6-hydroxybenzo[d]oxazole, respectively. Next, these substrates were O-alkylated with 4-vinylbenzyl chloride, allyl bromide and propargyl bromide with a view of obtaining potential monomers that feature a benzoxazole moiety in their structure. In addition, O-alkylation of these hydroxybenzoxazoles with methyl bromoacetate afforded the related heteroaryloxyacetic esters, which could be considered as an entry toward carboxylic acid derivatives carrying a benzoxazole fragment. Furthermore, benzaldehydes and acetophenones bearing a benzoxazole ring system were obtained through the reaction of these hydroxybenzoxazoles with 3-chloromethyl-4-methoxybenzaldehyde and 3-chloromethyl-4-methoxyacetophenone. Also, a pyrazoline–benzoxazole hybrid was synthesized from 6-hydroxy-2-methylbenzo[d]oxazole and a pyrazoline with a bromoacetyl substituent at N1.
Corrosion of iron in acidic media remains a major industrial challenge, creating a need for environmentally friendly corrosion inhibitors. In this study, the corrosion inhibition performance of Cucurbita pepo leaf extract as a surface pretreatment for mild iron electrodes in 1 M HCl was evaluated using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and thermodynamic analyses. Particular attention was given to the effects of immersion time and temperature on the inhibition mechanism. The electrochemical results showed a progressive improvement in inhibition efficiency with increasing immersion time. The pretreated electrodes exhibited a marked decrease in corrosion current density, and polarization measurements revealed a maximum inhibition efficiency of 97.46% after 24 h at 20 °C. The small shift in corrosion potential and the variation of both anodic and cathodic Tafel slopes indicated mixed-type inhibition behavior. EIS measurements confirmed the enhanced corrosion protection, with the charge transfer resistance increasing from 12.8 Ω for the blank solution to 211.2 Ω after 24 h of immersion. Thermodynamic analysis showed an increase in activation energy from 12.473 to 37.264 kJ mol⁻¹ in the presence of the extract, indicating a less favorable corrosion process. Increasing temperature reduced the inhibition efficiency, suggesting partial destabilization of the adsorbed protective layer. Overall, Cucurbita pepo leaf extract acts as an effective green corrosion inhibitor through adsorption-driven formation of a protective surface film.
The aim of this study was to determine the natural antioxidant properties of endemic Lophanthus turcicus (Nepeta turcica) based on its phenolic compound and vitamin content. Phenolic compounds and vitamins were determined by HPLC, while radical scavenging, Fe²⁺ chelating, and anti-hemolytic activitiy were determined spectrophotometrically. The main phenolic compounds identified were chrysin, naringin, trans-ferulic and chlorogenic acid, with values measured as 1502.03 ± 155.19, 411.37 ± 0.19, 236.63 ± 1.73 and 52.44 ± 2.77 µg/g dry weight, respectively. Vitamin levels were determined as retinol (2.20 ± 0.16) > alpha-tocopherol (1.55 ± 0.19) > phylloquinone (0.34 ± 0.096) µg/g dw. Radical scavenging activity tests, metal chelating and antihemolytic analyses of the methanol extract showed that the plant has a significant antioxidant activity in vitro. In particular, metal chelating activity (IC50 36.93 ± 3.39 μg/mL) was found to be very close to the values of the reference BHT (IC50 30.20 ± 0.54 μg/mL). Determination of anti-hemolytic activity (plant IC50 75.26 ± 2.30 μg/mL; Trolox: 59.55 ± 1.81 μg/mL) indicates that L. turcicus may protect the cell membrane against oxidative damage. These findings suggest that the plant contains biologically active compounds and may be a properties source of natural antioxidants.
