Ultrafine Pt nanoparticles supported on a dendrimer containing thiol groups: an efficient catalyst for the synthesis of benzimidazoles and benzothiazoles from benzyl alcohol derivatives in water

A review on synthesis, capping and applications of superparamagnetic magnetic nanoparticles

Magnetic nanoparticles (MNPs) have garnered significant attention from researchers due to their numerous technologically significant applications in diverse fields, including biomedicine, diagnostics, agriculture, optics, mechanics, electronics, sensing technology, catalysis, and environmental remediation. The superparamagnetic nature of MNP is exploited for many applications and remains fascinating to study many fundamental phenomena. The uniqueness of this review is that it gives an in-depth review of different synthesis approaches adopted for preparing magnetic nanoparticles and nanoparticle formation mechanisms, functionalizing them with different capping agents, and applying different functionalized magnetic nanoparticles. The important synthesis techniques covered include coprecipitation, microwave-assisted, sonochemical, sol-gel, microemulsion, hydrothermal/solvothermal, thermal decomposition, and mechano-chemical synthesis. Further, the advantages and disadvantages of each technique are discussed, and tables show important results of prepared particles. Other aspects covered in this review are the dispersion of magnetic nanoparticles in the continuous matrix, the influence of surface capping on high-temperature thermal stability, the long-term stability of ferrofluids, and applications of functionalized magnetic nanoparticles. For effective utilization of the ferrite nanoparticles, it is essential to formulate thermally and colloidally stable magnetic nanoparticles with desired magnetic properties. Capping enhances the phase transition temperature and long-term colloidal stability. Magnetic nanoparticles capped or functionalized with specific binding species, specific components like drugs, or other functional groups make them suitable for applications in biotechnology/biomedicine. Recent studies reveal the tremendous scope of MNPs in therapeutics and theranostics. The requirements for nanoparticle size, morphology, and physio-chemical properties, especially magnetic properties, functionalization, and stability, vary with applications. There are also challenges for precise size control and the cost-effective production of nanoparticles in large quantities. The review should be an ideal material for researchers working on magnetic nanomaterials and an excellent reference for freshers.

Palladium-immobilized triazine dendrimer on magnetic nanoparticles: as reusable microreactor for solvent-dependent synthesis strategy of 2,3-diphenylindoles and pentaphenylpyrrole derivatives

In this work, we demonstrate that palladium-immobilized triazine dendrimer on magnetic nanoparticles in proper solvents, provides an impressive, atom-economical and compelling approach for the selective synthesis of 2,3-diphenylindole or pentaphenylpyrrole derivatives via annulation of diphenylacetylene with diverse anilines. Both the annulation methods were taken place under copper- and phosphine-free conditions with high yields at air atmosphere. Likewise, bis-indoles were obtained with excellent yields under optimized reaction conditions. Besides, the catalyst was isolated and reused for seven cycles without decrease potential of catalytic activity. Two mechanistic pathways were proposed and geometry optimizations, electronic properties as well as vibrational characterizations of all structures were performed with density functional theory (DFT). Also, the investigation of atomic basin properties of these molecular systems was carried out utilizing the quantum atoms-in-molecules theory (QTAIM). The results showed that 2,3-diphenylindole and pentaphenyl pyrrole molecular systems can be used as intramolecular acceptor/donor (n-like/p-like) sections.

Synthesis, Antimicrobial and Antibiofilm Activities, and Molecular Docking Investigations of 2-(1H-Indol-3-yl)-1H-benzo[d]imidazole Derivatives

The treatment of many bacterial and fungal infections remains a problem due to increasing antibiotic resistance and biofilm formation by pathogens. In the present article, a methodology for the chemoselective synthesis of 2-(1H-indol-3-yl)-1H-benzo[d]imidazole derivatives is presented. We report on the antimicrobial activity of synthesized 2-(1H-indol-3-yl)-1H-benzo[d]imidazoles with significant activity against Staphylococcus aureus ATCC 25923, Staphylococcus aureus ATCC 43300 (MRSA), Mycobacterium smegmatis (mc(2)155/ATCC 700084), and Candida albicans ATCC 10231. High activity against staphylococci was shown by indolylbenzo[d]imidazoles 3ao and 3aq (minimum inhibitory concentration (MIC) < 1 µg/mL) and 3aa and 3ad (MIC 3.9-7.8 µg/mL). A low MIC was demonstrated by 2-(1H-indol-3-yl)-1-methyl-1H-benzo[d]imidazole (3ag) against M. smegmatis and against C. albicans (3.9 µg/mL and 3.9 µg/mL, respectively). 2-(5-Bromo-1H-indol-3-yl)-6,7-dimethyl-1H-benzo[d]imidazole (3aq) showed a low MIC of 3.9 µg/mL against C. albicans. Compounds 3aa, 3ad, 3ao, and 3aq exhibited excellent antibiofilm activity, inhibiting biofilm formation and killing cells in mature biofilms. Molecular docking analysis identified three potential interaction models for the investigated compounds, implicating (p)ppGpp synthetases/hydrolases, FtsZ proteins, or pyruvate kinases in their antibacterial action mechanism.

Cerium Oxide Nanoparticles Confined in Doped Mesoporous Carbons: A Strategy to Produce Catalysts for Imine Synthesis

A group of (doped N or P) carbons were synthesized using soluble starch as a carbon precursor. Further, ceria nanoparticles (NPs) were confined into these (doped) carbon materials. The obtained solids were characterized by various techniques such as N2 physisorption, XRD, TEM, SEM, XPS, and XAS. These materials were used as catalysts for the oxidative coupling between benzyl alcohol and aniline as the model reaction. Ceria immobilized on mesoporous-doped carbon shows higher activity than the other materials, benchmark catalysts, and most of the previously reported catalysts. The control of the ceria NP size, the presence of Ce3+ cations, and an increment in the disorder in the ceria NP structure caused by a support-ceria interaction could increase the number of oxygen vacancies and improve its catalytic performance. CN-meso/CeO2 was also used as the catalyst for a rich scope of substrates, such as substituted aromatic alcohols, linear alcohols, and different types of amines. The influence of various reaction parameters (substrate content, reaction temperature, and catalyst content) on the activity of this catalyst was also checked.

Research Progress in Organic Synthesis by Means of Photoelectrocatalysis

The rapid development of radical chemistry has spurred several innovative strategies for organic synthesis. The novel approaches for organic synthesis play a critical role in promoting and regulating the single-electron redox activity. Among them, photoelectrocatalysis (PEC) has attained considerable attention as the most promising strategy to convert organic compounds into fine chemicals. This review highlights the current progress in organic synthesis through PEC, including various catalytic reactions, catalyst systems and practical applications. The numerous catalytic reactions suffer the high overpotential and poor conversion efficiency, depending on the design of electrolyzers and the reaction mechanisms. We also considered the recent developments with special emphasis on scientific problems and efficient solutions, which enhance accessibility to utilize and further develop the photoelectrocatalytic technology for the specific chemical bonds formation and the fabrication of numerous catalytic systems.