Articles
Journal of Molecular Structure (00222860)1330
The conformational analysis of three 3,5-disubstituted 4,5-dihydro-1,2,4-oxadiazoles (DHOZs) was investigated using X-ray crystal structure and DFT computations. Mechanistically, nucleophilic attack of either the hydroxy or the amino group of the amidoxime precursor to the re- or si-faces of the aldehyde carbonyl group and the following intramolecular cyclization results normally in the formation of the R/S-enantiomeric pair with the stereocenter on the C5-atom of the heterocyclic ring. Surprisingly, the crystal packing of the investigated compounds revealed the presence of the pure R-enantiomer, pure S-enantiomer, and the racemic mixture. The optical activities of the molecules are confirmed by recording their CD spectra. Crystal packing is explored based on the acting intra- and intermolecular interactions using the quantum theory of atoms-in-molecules (QTAIM), noncovalent interaction plot (NCI plot), reduced density gradient (RDS), Hirshfeld surface (HS) analysis, and two-dimensional fingerprint (2D-FP) plots. The computational structural characteristics of the optimized geometries of the considered DHOZs are compatible with those in the crystal packing. Furthermore, the computational conformational analysis of the imino-oxime intermediate, involved in the intramolecular cyclization process, support the experimental findings. © 2025
ACS Omega (24701343)10(19)pp. 19705-19713
Push-pull compounds including the 4-formylphenoxy group linked by saturated multimethylene bridges (CH2)n=2-4 forming bis-aldehydes were designed and synthesized. The effects of the flexibility and electronic nature of the multimethylene bridges on the 1H NMR and UV spectroscopic characteristics and the fluorescence ability of these bis-aldehydes were investigated in different solvents. The results indicated that with an increase in the length of the multimethylene bridge, the inductive effect is enhanced, and a bathochromic shift and hyperchromic effect in their UV spectra were observed. The locally excited (LE) and intramolecular charge transfer (ICT) emission levels were observed in their fluorescence spectra, but the emission resulting from possible excimer formation was not observed. Additionally, the fluorescence emissions from the LE and ICT levels are intensified in the nonpolar and polar solvents, respectively. Density functional theory (DFT) computational results indicated that most of the UV transitions are of the π-π* nature and from the bridge side of each aryl ring toward the attached chromophore of the same aryl ring. © 2025 The Authors. Published by American Chemical Society.
Rastegari, F.,
Asghari, S.,
Mohammadpoor baltork, I.,
Sabzyan, H.,
Tangestaninejad, S.,
Moghadam, M.,
Mirkhani, V. Journal of Hazardous Materials (18733336)476
A novel imine-linked COF is synthesized by the condensation of 2,4,6-tris(4-aminophenyl)−1,3,5-triazine (TAPT) and 2-hydroxy-5-methoxyisophthalaldehyde (HMIPA) under solvothermal conditions. This COF adsorbs preferentially the neutral dye Neutral Red (NR) over the positively charged dye Methylene Blue (MB) at pH 7, and the negatively charged Methyl Orange (MO) over the positively charged Methylene Blue (MB) at pH 3. The maximum adsorption capacities (qe) obtained within very short times (11–60 min) under optimized conditions were 108, 185 and 429 mg.g−1 for the MB, MO, and NR dyes, respectively. These adsorptions obey the Langmuir isotherm and pseudo-second-order kinetics. The prepared TAPT-HMIPA-COF is used successfully for the removal of the dyes from real water and treated wastewater samples. The adsorption data, BET, FTIR, and zeta potential measurements show that the electrostatic, π-π stacking and hydrogen bond interactions are responsible for the adsorption of organic dyes on the surface of the prepared COF. Due to recyclability, high capacity and efficiency for the adsorption of positive, negative and neutral organic dyes, this COF can be considered promising for simultaneous removal of various dyes from aqueous solutions at adjusted pHs. © 2024 Elsevier B.V.
Arabian, S.,
Gordanshekan, A.,
Farhadian, M.,
Solaimany nazar a.r., A.R.,
Tangestaninejad, S.,
Sabzyan, H. Chemical Engineering Journal (13858947)488
This study investigated the photocatalytic adsorption, degradation, and mineralization of Cefixime (CFX) through hydrothermally synthesized Bi2WO6(36 %)/g-C3N4(54 %)/ZIF-67(10 %) dual S-scheme heterojunction (BCZ). Full characterization analysis for the fresh and reused photocatalyst was explored to study the formation of heterojunction, stability, and reusability of the BCZ. VB-XPS, Mott-Schottky plots, and UV–Vis DRS defined the band structure and electron transfer mechanism of BCZ. The effects of ten operating condition factors, including reaction time, initial concentration of CFX, the dosage of photocatalyst, reaction temperature, initial pH of the reaction, visible and UV intensity, and concentration of Na2SO4, NaOH, and NaCl in the reaction solution were experimentally investigated. These factors were then modeled through artificial neural networks (ANN). The number of neurons, training algorithm, and the type of activation functions in the ANN were optimized by mean squared error metric followed by the visualizations of the ANN predictions. Two cost functions (the ratio of instantaneous CFX concentration to initial CFX concentration (C/C0) and the ratio of photocatalyst dosage to the amount of CFX removed) were employed to optimize the value of these operating condition factors separately and simultaneously through single and multi-objective genetic algorithms. Coupling LC-MS results and DFT calculations, a degradation pathway for Cefixime was proposed and then analyzed by QSAR. The toxicity of the treated solution was investigated using the wheat seed culture, along with MIC and MBC testing conducted by E. coli and S. aureus, and its eco-friendliness was confirmed by TOC and COD. Furthermore, ICP-OES confirmed that BCZ is a green photocatalyst. © 2024 Elsevier B.V.
