Exploration of new methodologies to tune catalytic selectivity is a long-sought goal in catalytic community. In this work, oil-water interfaces of Pickering emulsions are developed to effectively regulate catalytic selectivity of hydrogenation reactions, which was achieved via a precise control of the spatial distribution of metal nanoparticles at the droplet interfaces. It was found that Pd nanoparticles located in the inner interfacial layer of Pickering droplets exhibited a significantly enhanced selectivity for -chloroaniline (up to 99.6%) in the hydrogenation of -chloronitrobenzene in comparison to those in the outer interfacial layer (63.6%) in pure water (68.5%) or in pure organic solvents (46.8%). Experimental and theoretical investigations indicated that such a remarkable interfacial microregion-dependent catalytic selectivity was attributed to the microenvironments of the coexistence of water and organic solvent at the droplet interfaces, which could provide unique interfacial hydrogen-bonding interactions and solvation effects so as to alter the adsorption patterns of -chloronitrobenzene and -chloroaniline on the Pd nanoparticles, thereby avoiding the unwanted contact of C-Cl bonds with the metal surfaces. Our strategy of precise spatial control of catalysts at liquid-liquid interfaces and the unprecedented interfacial effect reported here not only provide new insights into the liquid-liquid interfacial reactions but also open an avenue to boost catalytic selectivity.
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http://dx.doi.org/10.1021/jacs.2c12120 | DOI Listing |
Polymers (Basel)
December 2024
Catalysis Research Group (CRG), Department of Chemistry, College of Science, King Khalid University, P.O. Box 9004, Abha 61413, Saudi Arabia.
This work focuses on the preparation and application of silver nanoparticles/organophilic clay/polyethylene glycol for the catalytic reduction of the contaminants methylene blue (MB) and 4-nitrophenol (4-NP) in a simple and binary system. Algerian clay was subjected to a series of treatments including acid treatment, ion exchange with the surfactant hexadecyltrimethylammonium bromide (HTABr), immobilization of polyethylene glycol polymer, and finally dispersion of AgNPs. The molecular weight of polyethylene glycol was varied (100, 200, and 4000) to study its effect on the stabilization of silver nanoparticles (AgNPs) and the catalytic activity of the resulting samples.
View Article and Find Full Text PDFPharmaceuticals (Basel)
December 2024
Biochemistry and Molecular Biology Department, Dasman Diabetes Institute, Dasman 15462, Kuwait.
: The mammalian target of the rapamycin (mTOR) signaling pathway is a central regulator of cell growth, proliferation, metabolism, and survival. Dysregulation of mTOR signaling contributes to many human diseases, including cancer, diabetes, and obesity. Therefore, inhibitors against mTOR's catalytic kinase domain (KD) have been developed and have shown significant antitumor activities, making it a promising therapeutic target.
View Article and Find Full Text PDFMolecules
December 2024
Department of Organic Chemistry, College of Chemistry, Beijing University of Chemical Technology, Beijing 100029, China.
In this study, an iridium-catalyzed selective 1,4-reduction of α,β-unsaturated carbonyl compounds is realized, with water as a solvent and formic acid as a hydride donor. The new efficient iridium catalyst features a 2-(4,5-dihydroimidazol-2-yl)quinoline ligand. The chemoselectivity and catalyst efficiency are highly dependent on the electronic and steric properties of the substrates.
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December 2024
State Key Laboratory of Molecular Engineering of Polymers, Laboratory of Advanced Materials, Shanghai Key Lab of Molecular Catalysis and Innovative Materials, Department of Chemistry, Fudan University, Shanghai 200438, China.
With the development and improvement of analysis and detection systems, low-toxicity and harmless detection systems have received much attention, especially in the field of food detection. In this paper, a low-toxicity dual-emission molecularly imprinted fluorescence sensor (CdTe QDs@SiO/N-CDs@MIPs) was successfully designed for highly selective recognition and visual detection of tetracycline (TC) in food samples. Specifically, the non-toxic blue-emission N-doped carbon dots (N-CDs) with high luminous performance acted as the response signals to contact TC via the covalent bond between amino and carboxyl groups.
View Article and Find Full Text PDFMolecules
December 2024
High & New Technology Research Center of Henan Academy of Sciences, No. 56 Hongzhuan Road, Zhengzhou 450002, China.
A series of colorful binuclear Schiff bases derived from the different diamine bridges including 1,2- ethylenediamine (bis-Et-SA, bis-Et-4-NEt, bis-Et-5-NO, bis-Et-Naph), 1,2-phenylenediamine (bis-Ph-SA, bis-Ph-4-NEt, bis-Ph-5-NO, bis-Ph-Naph), dicyano-1,2-ethenediamine (bis-CN-SA, bis-CN-4-NEt, bis-CN-5-NO, bis-CN-Naph) have been designed and prepared. The optical properties of these binuclear Schiff base ligands were fully determined by UV-Vis absorption spectroscopy, fluorescence emission spectroscopy, and time-dependent-density functional theory (TD-DFT) calculations. The inclusion of D-A systems and/or π-extended systems in these binuclear Schiff base ligands not only enables adjustable RGB light absorption and emission spectra (300~700 nm) but also yields high fluorescence quantum efficiencies of up to 0.
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