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The Cu-catalysed azide-alkyne cycloaddition (CuAAC) reaction, also known as the "click" reaction, is a powerful tool in organic synthesis due to its high efficiency, regioselectivity, and mild reaction conditions. However, the use of homogeneous copper catalysts often leads to challenges like separation and disposal, limiting their applicability in industrial settings. This study aimed to develop a novel heterogeneous catalyst utilizing NiO/Cu2O/CuO nanocomposites (NCs) for the selective and efficient synthesis of 1,4-disubstituted-1,2,3-triazoles via the click reaction. NiO/Cu2O/CuO NCs were prepared by a simple co-precipitation method. The catalytic activity of the prepared NCs was evaluated for the one-pot, three-component click reaction between benzyl bromide analogues, sodium azide, and phenyl acetylene under various conditions: ambient temperature, thermal heating, and microwave irradiation. The reaction progress was monitored by TLC, and the products were isolated and characterized by SEM, FTIR, XRD, and XPS. The NiO/Cu2O/CuO NCs exhibited superior catalytic performance compared to Cu2O/CuO nanoparticles (NPs). They facilitated the exclusive formation of the desired 1,4-isomer under all tested conditions. Notably, under microwave irradiation, the NiO/Cu2O/CuO NCs delivered significantly higher yields (89–96%) compared to Cu2O/CuO NPs (76–82%) for diverse triazole compounds. Characterization confirmed the successful synthesis of the NCs and the purity of the triazole products. Utilizing water as the solvent under microwave irradiation offered several advantages, including faster reaction rates, higher yields, efficient product isolation, and excellent recyclability of the catalyst. This study demonstrates the effectiveness of NiO/Cu2O/CuO NCs as a novel heterogeneous catalyst for the selective and efficient synthesis of 1,4-disubstituted-1,2,3-triazoles. The simple and efficient method, coupled with the advantages of water as a solvent and microwave-assisted heating, presents significant potential for various applications in organic synthesis and beyond. [ABSTRACT FROM AUTHOR]

In this study, the hydrolysis of TiCl4 was utilized to synthesize titanium dioxide clusters (TiO2 NCs) at a sub-nanometer scale. Precise control over the synthesis process resulted in the production of stable particles with well-defined size distributions. These TiO2 NCs were specifically developed to facilitate the conversion of SOx into organo-sulfonic acid derivatives under visible light irradiation. Various characterization techniques such as TEM, EDX, XRD, UV–Vis-DRS, Raman, and FTIR were employed to analyze the formed photocatalysts, including TiO2 nanoparticles (NPs) and NCs. The efficiency of catalytic SOx removal depended significantly on the particle size and surface area of the nanocatalysts, as well as the presence of thymol or naphthol (1,2). These materials (1,2) proved to be highly effective in removing SOx from flue gas under ambient conditions, specifically at room temperature. The conversion of thymol or naphthol involved a combination of adsorption and catalytic oxidation–reduction reactions. This photocatalytic approach for SOx conversion offers several advantages, including high performance, elimination of the need for high temperature or pressure, and rapid catalytic removal within a short reaction time of 10 min. TiO2 NCs demonstrate high efficiency in SOx removal, offering a promising solution for pollution control. Unlike some other methods, TiO2 nanoparticles can be potentially regenerated and reused, making them a more sustainable approach. [ABSTRACT FROM AUTHOR]

Heterocyclic pyridazine continues to attract great interest, mainly arising from a large variety of interesting pharmacological activities, herbicides, insecticides, and fungicides. On the other hand, the current interest in selenium-containing heterocycles is a result of their chemical properties and biological activities. In addition to the many recent publications dealing with the pharmacological potential of a selenium compound, new active formulations are an attractive target for chemical research. 2-((3-cyano-4,6-dimethylpyridin-2-yl)selanyl) acetic acid (pyd-Se), 2-((4-cyano-5,6-diphenylpyridazin-3-yl)selanyl)acetic acid (pydz-Se) and 2-((4,6-dimethyl quinolin-2-yl)selanyl)acetic acid (quin-Se) reacts with gold(III) chloride to produce metal ion complexes of specific composition. These synthesized complexes were characterized by elemental analyses, molar conductivity, FTIR, 1H NMR and transmission electron microscopy (TEM) investigations. The complexes were found to have the formulas [Au(pyd-Se)2]Cl, [Au(pydz-Se)2]Cl and Au(quin-Se)2]Cl, respectively. [ABSTRACT FROM AUTHOR]

Both 2‐(N‐arylcarbamoyl)methylsulfanyl‐3‐cyano‐5‐ethoxycarbonyl‐6‐methyl‐4‐(2′‐thienyl)pyridines 2a‐e and their isomers, 3‐amino‐2‐(N‐arylcarbamoyl)‐5‐ethoxy‐carbonyl‐6‐methyl‐4‐(2′‐thienyl)thieno[2,3‐b]pyridines 3a‐e were synthesized by reaction of ethyl 3‐cyano‐1,2‐dihydro‐6‐methyl‐4‐(2′‐thienyl)‐2‐thioxopyridine‐5‐carboxylate (1) with the respective N‐aryl‐2‐chloroacetamides in the presence of different basic catalysts. Compounds 3a‐e were used as precursors for synthesizing of pyridothienopyrimidinones 4a‐e, pyridothienotriazinones 5a‐e and tetrahydropyridothienopyrimidinones 6a‐c via treatment with triethyl orthoformate, nitrous acid, and/or 4‐chlorobenzaldehyde respectively. The photophysical properties of aminothienylthienopyridines 3a‐e and tetrahydropyridothieno‐pyrimidine‐4(3H)‐ones 6a‐c were studied and the fluorescence data revealed that all selected compounds possess AIE behaviors in solution and in solid state. Most of the prepared compounds were evaluated in vitro for their antibacterial and antifungal activities, and considerable results were obtained. Moreover, the cytotoxic activity of thienopyridines 3a‐d against MCF‐7 and HepG2 cell lines was evaluated and they showed moderate to very strong activity. [ABSTRACT FROM AUTHOR]