Abstract: The removal of synthetic dyes from wastewater is an urgent environmental issue due to their toxicity and persistence. This study explores the use of White Bean Straw, an abundant agricultural residue, as a low-cost and eco-friendly adsorbent for removing Malachite Green and Methyl Red in a fixed-bed system. Adsorption experiments examined the effects of bed height, flow rate, and dye concentration. Optimal performance occurred at a 5 mL/min flow rate, 10 mg/L dye concentration, and 2 cm bed height, achieving adsorption capacities of 28.96 mg/g for Malachite Green and 27.27 mg/g for Methyl Red dyes. Higher bed height and dye concentration enhanced efficiency, while lower flow rates improved performance. Breakthrough data fitted well with the Adams–Bohart, Thomas, and Yoon–Nelson models (R² ranged from 0.921 to 0.986). Overall, White Bean Straw proved to be an effective, sustainable, and low-cost adsorbent for dye-contaminated wastewater treatment.

Abstract: Some new 2-(2H-chromen-3-yl)-[1,3,4]oxadiazole derivatives 8a-e using Huisgen synthesis of 1,3,4-oxadiazoles reaction. Their structures were verified by 1H NMR and and elemental analyses. Compounds 8a-e were tested against 60 human cancer cell lines for in vitro cytotoxic activities according to the international scientific programme of the US National Institute of Health – DTP (Developmental Therapeutics Program), National Cancer Institute (Bethesda, Maryland, USA). Compounds with moderate activity against certain cancer cell lines were identified. In addition, in collaboration with CO-ADD (The Community for Open Antimicrobial Drug Discovery), we have studied the antibacterial activity against the ESCAPE group of strains and the antifungal activity against C. Albicans ATCC 90028 and C. Neoformans ATCC 208821. The studies allowed us to identify 3-[5-(6-bromo-2H-chromen-3-yl)-[1,3,4]oxadiazol-2-yl]-pyridine as a compound with high antibacterial activity against E. Coli ATCC 25922 with MIC 8 μg/ml. Docking studies have shown high affinity of this compound for the bacterial DNA gyrase of Escherichia coli.

Abstract: Dye-sensitized solar cells (DSSCs) represent a highly promising new generation of photovoltaic devices that offer an attractive alternative to traditional silicon-based solar cells due to their low production costs, simple manufacturing, and adaptable optoelectronic properties. Titanium dioxide (TiO₂) is extensively utilized as a semiconductor in DSSCs due to the favorable position of its conduction band, high chemical stability, abundance, and non-toxicity. As part of this work, an in-depth computational study was conducted on five organic dyes (D1 to D5) to investigate their potential as effective sensitizers for DSSC applications. Density functional theory (DFT) and time-dependent DFT (TD-DFT) were employed to investigate their structural, electronic, and optical properties, as well as their key photovoltaic parameters. The HOMO energy levels calculated (−5.99 to −6.36 eV) were low enough to allow efficient dye regeneration by the electrolyte, while the LUMO levels (−3.05 to −3.71 eV) were located above the conduction band edge of TiO₂ (−4.0 eV), Calculated band gaps (2.35–2.94 eV) supported strong absorption in the visible range, and open-circuit voltages (0.26–0.94 eV) suggested good photovoltaic potential. Furthermore, all dyes presented positive free electron injection energy (ΔGinject), evidencing thermodynamically favorable charge transfer processes. Benchmarking revealed that structural modifications between dyes were found to be significantly.

Abstract: The reactions between 2,3-dimethylbutadiene and six azodicarbonyl derivatives give the aromatic α-amino ketone family which presents a great interest in chemical synthesis and especially in polymerization reactions. This reaction was studied using the Molecular Electron Density Theory. The reaction pathways were established using the Intrinsic Reaction Coordinate (IRC) method and confirmed through topological analysis of the Electron Localization Function (ELF). The substituent effect was discussed from the CDFT and GEDT calculations. The temporary formation of hydrogen bonds at TSs is responsible for the mechanistic aspect and the process asynchronous of new bond formation. Consequently, the reaction proceeds via a non-concerted in two-stages mechanism. Finally, we investigated the potential inhibitory effects of six products against HIV-1-Mpro through molecular docking calculations. Then, their medicinal potential and physicochemical properties were scrutinized, employing the SwissADME server, unveiling their non-toxic characteristics and positioning them as promising contenders for drug development.

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Abstract: This study presents the synthesis and characterization of the compound 5,5'-(methylenebis(1,3,4-oxadiazole-5,2-diyl))bis(benzene-1,3-diamine), by ¹H NMR, ¹³C NMR and FTIR-ATR infrared spectroscopy and mass spectrometry. A theoretical study was carried out by a comprehensive and hierarchical methodology in order to evaluate the inhibitory behavior of the molecule 5,5'-(methylenebis(1,3,4-oxadiazole-5,2-diyl))bis(benzene-1,3-diamine) with respect to the corrosion of a Fe(110) type metal surface. Thus, examination of non-covalent interactions by NCI analysis. In addition, the study of adsorption on the metal surface was carried out by the Monte Carlo method.

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Abstract: This study explores the mechanism and solvent effects of the (3+2) cycloaddition between N-(4-(prop-2-yn-1-yloxy)phenyl)-1-(pyridin-2-yl)methanimine and 4-azido-7-chloroquinoline, yielding quinoline–triazole hybrids. DFT/B3LYP/6-311G+(d,p) calculations, supported by ELF and NPA analyses, reveal a one-step mechanism favoring product P1 both kinetically and thermodynamically. Non-covalent interaction (NCI) analysis indicates that TS1 is stabilized by hydrogen-bonding and van der Waals interactions. ADMET screening showed that all cycloadducts are non-toxic (no AMES mutagenicity or skin sensitization). Molecular docking identified P3 and P4 as the most potent ligands for Plasmodium falciparum kinases 5E16 and 5DYK, respectively, with stronger binding affinities than chloroquine. Molecular dynamics simulations further confirmed the structural stability of the P3–5E16 and P4–5DYK complexes, highlighting these derivatives as promising candidates for antimalarial drug development.

Abstract: Herein, we theoretically design four new π-conjugated thieno[3,4-b]pyrazine derivatives for organic solar cells (OSCs), denoted 2,3-di([2,2′:5′,2″:5″,2‴-quaterthiophen]-5-yl)-5,7-di(thiophen-2-yl)thieno[3,4-b]pyrazine, 2,3-bis(5'''-(4-fluorophenyl)-[2,2':5',2'':5'',2'''-quaterthiophen]-5-yl)-5,7-di(thiophen-2-yl)thieno[3,4-b]pyrazine, 2,3-bis(5'''-(4-methoxyphenyl)-[2,2':5',2'':5'',2'''-quaterthiophen]-5-yl)-5,7-di(thiophen-2-yl)thieno[3,4-b]pyrazine, and 2,3-bis(5'''-(9-methyl-9H-carbazol-2-yl)-[2,2':5',2'':5'',2'''-quaterthiophen]-5-yl)-5,7-di(thiophen-2-yl)thieno[3,4-b]pyrazine. The geometric, electronic, optical, photovoltaic, and nonlinear optical (NLO) properties of the investigated chemical structure were investigated using Density Functional Theory (DFT) and Time-Dependent DFT (TD-DFT) calculations at the B3LYP/6-31G(d,p) level. Structural changes on the chemical structure induce a narrow energy gap in the range (2.08 – 2.12 eV), and an enhancement of the absorption in the visible range (λ_max = 682 – 688 nm). In addition, a low value of exciton binding energies is obtained (E_b = 0.28 – 0.31 eV). Analysis of the density of states (DOS), transition density matrix (TDM), electron localization function (ELF), and localized orbital locator (LOL) showed effective charge delocalization and donor-to-acceptor electron transfer. The photovoltaic performance was assessed using the open circuit voltage (V_oc) obtained between Highest Occupied Molecular Orbital (HOMO) donor to Lowest Unoccupied Molecular Orbital (LUMO) acceptor levels and was found promising (V_oc = 1.32 – 1.44 V). The large hyperpolarizability and high nonlinearity response of the NLO results also indicated the potential for these molecules to be used in various optoelectronic applications.

Abstract: A series of novel conjugates of nalidixic acid with a marine natural product was designed and synthesized. Their antibacterial and antibiofilm activities were evaluated in vitro against Gram-positive (S. aureus ) and Gram-negative (E. coli and P. aeruginosa) bacteria. Most of the compounds exhibited strong antibacterial activity against S. aureus, E. coli, and P. aeruginosa strains, except for the oxacillin-resistant P. aeruginosa. Among them, compound 2, containing a decyl ammonium fragment, showed the highest antibacterial activity, with MIC values ranging from 2 to 8 μg/mL, superior to those of nalidixic acid. In addition, compound 2 inhibited biofilm formation by standard strains of S. aureus, E. coli, and P. aeruginosa, and by colistin-resistant E. coli by 98-100% at a concentration of 4 μg/mL.

Abstract: This work presents a density functional theory study of Ofloxacin (OFL) as a medicine with antibiotic activity. The Conformational behaviour, gas-phase acidity and metal ion affinity (MIA) analysis of the Ofloxacin with some selected cations from alkali (Li⁺, Na⁺, and K⁺), alkaline-earth (Be²⁺, Ca²⁺ and Mg²⁺) and transition (Zn²⁺, Cu²⁺, Ni²⁺, Co²⁺ and Fe²⁺) metals were explored. All structural optimizations were performed at the M06–2X level of theory with 6-311++G(d,p) using the basis set. The calculations demonstrated the following MIA order: OFL-Be²⁺ > OFL-Ni²⁺ > OFL-Co²⁺ > OFL-Cu²⁺ > OFL-Fe²⁺ > OFL-Zn²⁺ > OFL-Mg²⁺ > OFL-Ca²⁺ > OFL-Li⁺ > OFL-Na⁺ > OFL-K+. The results also showed that the MIA values are decrease in aqueous solution because of solvation effects. Natural bond orbital theory (NBO) and quantum theory of atoms in molecules (QTAIM) were used to probe the charge transfer process and the nature of interactions in the formed complexes. The results of the NBO analysis revealed that the charge transfer occurs from OFL and Mn+ with the metal cations acting as charge acceptors and the amount of charge transfer is in agreement with MIA. The QTAIM analysis shows that the (M–O) coordination interactions are quasi-covalent in complexes formed between OFL and alkali or alkaline-earth metal cations, whereas they are covalent in complexes formed with the transition metal cations and Be²⁺. The results confirm that the strengths of the interactions are in good agreement with electron densities at the bond critical points (BCP).

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Abstract: A convenient method has been developed for the synthesis of a focused library of eight 3-arylimidazo[2,1-b][1,3]thiazoles 4a–h, seven of which have been obtained for the first time. The approach is based on the cyclization of 2-(aroylmethylthio)imidazoles 3a–h under the action of polyphosphoric acid. The structure of the intermediate derivatives of thioimidazoles 3a-h and the imidazothiazoles 4a-h thus obtained was characterized using ¹H, ¹³C NMR spectra and LC-MS. Testing all obtained compounds for antioxidant activity showed that 2-[(1H-imidazol-2-yl)thio]-1-arylethanones 3a–h exhibit a higher ability to inhibit DPPH radicals compared to their cyclic analogues, 3-arylimidazo[2,1-b]thiazoles 4a–h. The highest antioxidant activity was demonstrated by compound 3b (I = 96.3%), which also showed high binding affinity to the Kelch domain of the Keap1 protein in docking studies.

DOI: 10.5267/j.ccl.2025.12.002
Keywords: Imidazo[2,1-b][1,3]thiazone, Polyphosphoric acid, Еlectrophilic intramolecular cyclization, Antioxidant activity

Supplementary data PDF (4600 K)