The search for versatile heterogeneous catalysts with multiple active sites for broad asymmetric transformations has long been of great interest, but it remains a formidable synthetic challenge. Here we demonstrate that multivariate metal-organic frameworks (MTV-MOFs) can be used as an excellent platform to engineer heterogeneous catalysts featuring multiple and cooperative active sites. An isostructural series of 2-fold interpenetrated MTV-MOFs that contain up to three different chiral metallosalen catalysts was constructed and used as efficient and recyclable heterogeneous catalysts for a variety of asymmetric sequential alkene epoxidation/epoxide ring-opening reactions. Interpenetration of the frameworks brings metallosalen units adjacent to each other, allowing cooperative activation, which results in improved efficiency and enantioselectivity over the sum of the individual parts. The fact that manipulation of molecular catalysts in MTV-MOFs can control the activities and selectivities would facilitate the design of novel multifunctional materials for enantioselective processes.
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http://dx.doi.org/10.1021/jacs.7b03113 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
Harvard University, Rowland Institute at Harvard, 02138, Cambridge, UNITED STATES OF AMERICA.
The dynamic response of heterogeneous catalytic materials to their environment opens a wide variety of possible surface states which may have increased catalytic activity. In this work, we find that it is possible to generate a surface state with increased catalytic activity over metallic 2nm Pt nanoparticles by performing a thermal treatment of the CO*-covered Pt catalyst. This state is characterised by its ability to oxidise CO to CO2 at room temperature.
View Article and Find Full Text PDFRSC Adv
January 2025
Department of Chemistry, Faculty of Science, University of Maragheh P.O Box 55181-83111 Maragheh Iran.
In this study, we present the design, synthesis, and utilization of a covalent triazine framework (CTF) formed by the condensation of , , -tris(4-(aminomethyl)benzyl)-1,3,5-triazine-2,4,6-triamine and 2,4,6-tris(4-formylphenoxy)-1,3,5-triazine on which silica is immobilized (TPT-TAT/silica) as an innovative catalyst for porphyrins synthesis. Under solvothermal conditions, the condensation of triamine and trialdehyde precursors led to the formation of a covalent triazine framework (CTF) with a high nitrogen content. The resulting CTF is characterized by its extensive porosity and elevated nitrogen levels, which are critical for the creation of catalytic active sites.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
University of North Texas, Department of Chemistry, 1508 W Mulberry St, 76201, Denton, UNITED STATES OF AMERICA.
Converting CO2 to high-value fine chemicals represents one of the most promising approaches to combat global warming and subsequently achieve a sustainable carbon cycle. Herein, we contribute an organoboron functionalized ultra-thin metal-organic nanosheet (MON), termed TCPB-Zr-NS, featuring an abundance of exposed Lewis acidic B and formate sites, which can effectively promote CO2 conversion upon the addition of Lewis basic o-phenylenediamines. Compared with the prototypical 3D analogue TCPB-Zr-3D, the resultant TCPB-Zr-NS showcases dramatically improved catalytic activity for the cyclization of o-phenylenediamine as a result of the highly exposed active sites and efficient substrates/products diffusion.
View Article and Find Full Text PDFChem Commun (Camb)
January 2025
Hunan Provincial Key Laboratory of Micro & Nano Materials Interface Science, College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan 410083, China.
A heterogeneous salen-based conjugated microporous polymer catalyst (CMP@Cu-salen) is prepared by a one-pot method for -formylation of amines with CO. The uniformly dispersed Cu-salen site and porous structure facilitates the enrichment of CO and transfer of substrates and the transformation. Our CMP@Cu-salen shows excellent catalytic performance (conversion: 99%, selectivity: 90%) for formylation of -methylaniline under mild conditions (0.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, P. R. China.
The microenvironment is recognized to be as crucial as active sites in heterogeneous catalysis. It was found that the catalytic activity of a set of chemical reactions can be significantly influenced by the confined space of carbon nanotubes (CNTs), with some reactions showing superior activity, while others experience a negative impact. The rational design of confined catalysis must rely on the accurate insights of confined microenvironment.
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