An official website of the United States government
Palladium-encapsulated covalent organic frameworks (Pd/COFs) have garnered enormous attention in heterogeneous catalysis. However, the dominant ex situ encapsulation synthesis is tedious (multistep), time-consuming (typically 4 days or more), and involves the use of noxious solvents. Here we develop a mechanochemical in situ encapsulation strategy that enables the one-step, timeefficient, and environmentally benign synthesis of Pd/COFs. By ball milling COF precursors along with palladium acetate (Pd(OAc)2) in one pot under air at room temperature, Pd/COF hybrids were readily synthesized within an hour, exhibiting high crystallinity, uniform Pd dispersion, and superb scalability up to gram scale. Moreover, this versatile strategy can be extended to the synthesis of three Pd/COFs. Remarkably, the resulting Pd/DMTP-TPB showcases extraordinary activity (96−99% yield in 1 h at room temperature) and broad substrate scope (>10 functionalized biaryls) for the Suzuki−Miyaura coupling reaction of aryl bromides and arylboronic acids. Furthermore, the heterogeneity of Pd/DMTP-TPB is verified by recycling and leaching tests. The mechanochemical in situ encapsulation strategy disclosed herein paves a facile, rapid, scalable, and environmentally benign avenue to access metal/COF catalysts for efficient heterogeneous catalysis.
more »
« less
This content will become publicly available on April 15, 2026
A Rapid, Sustainable, One‐step Mechanochemical Strategy for Synthesizing Gold Nanoparticle‐Doped Covalent Organic Frameworks
Abstract Doping gold nanoparticles within covalent organic frameworks (AuNPs@COFs) has garnered enormous momentum due to their unique properties and broad applications. Nevertheless, prevailing multi‐step synthesis is plagued with low time efficiency, eco‐unfriendliness, and tedious protocols. Herein, we introduce a rapid, sustainable, scalable, one‐step mechanochemical strategy for synthesizing up to four AuNPs‐doped COFs via steel ball milling within an hour under ambient conditions. This approach overcomes the synthetic barriers of conventional multi‐step solution‐based methods, such as extended reaction times (5 days), milligram scale, the use of toxic solvents, elevated temperatures, and reliance on external reducing agents. One exemplary AuNPs@COF (AuNPs@DMTP‐TPB) exhibits high crystallinity, porosity, small AuNP size, and uniform dispersion (5.4±0.6 nm), surpassing its counterpart synthesized via multi‐step solution‐based methods (6.4±1.1 nm). Notably, the gram‐scale synthesis of AuNPs@DMTP‐TPB can be successfully achieved. Control experiments suggest that thein situformation of AuNPs is attributed to the galvanic reduction of gold precursor by stainless steel apparatus. As a proof‐of‐concept catalytic application, AuNPs@DMTP‐TPB demonstrates remarkable catalytic activity and recyclability for the aqueous reduction of 4‐nitrophenol under ambient conditions. This study provides an environmentally benign and fast pathway to synthesize AuNPs@COFs via mechanochemistry for the first time, opening tremendous possibilities for heterogeneous catalysis and beyond.
more »
« less
- PAR ID:
- 10590334
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Chemistry – A European Journal
- Volume:
- 31
- Issue:
- 22
- ISSN:
- 0947-6539
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract The rapid and environmentally benign synthesis of metal‐immobilized covalent organic frameworks (metal/COFs) for heterogeneous catalysis is a pervasive challenge, as the mainstream synthesis is exceedingly time‐consuming (up to four days) and demands the use of hazardous solvents. Herein, we describe a sustainable and efficient one‐step sonochemical strategy for constructing diverse palladium (II)‐immobilized COFs (Pd(II)/COFs). By merging the sonochemistry‐assisted COF synthesis and in situ Pd (II) immobilization into a single step, this strategy enables the rapid formation of Pd(II)/COF hybrids within an hour under ambient conditions using water as the solvent. Notably, gram‐scale synthesis of Pd(II)/COFs is achievable. The resulting Pd(II)/COFs exhibit superb crystallinity and high surface area, leading to remarkable activity, excellent functionality tolerance, and high recyclability for the Suzuki–Miyaura cross‐coupling reaction of aryl bromides and arylboronic acids at room temperature. This one‐step sonochemical strategy effectively addresses the long‐lasting limitations of traditional multistep synthesis, paving a fast and sustainable avenue to diversified metal/COF hybrids for heterogeneous catalysis and potentially other applications.more » « less
-
Metal‐encapsulated covalent organic frameworks (metal/COFs) represent an emerging paradigm in heterogeneous catalysis. However, the time‐intensive (usually 4 or more days) and tedious multi‐step synthesis of metal/COFs remains a significant stumbling block for their broad application. To address this challenge, we introduce a facile microwave‐assistedin situmetal encapsulation strategy to cooperatively combine COF formation andin situpalladium(II) encapsulation in one step. With this unprecedented approach, we synthesize a diverse range of palladium(II)‐encapsulated COFs (termed Mw‐Pd/COF) in the air within just an hour. Notably, this strategy is scalable for large‐scale production (~0.5 g). Leveraging the high crystallinity, porosity, and structural stability, one representative Mw‐Pd/COF exhibits remarkable activity, functional group tolerance, and recyclability for the Suzuki‐Miyaura coupling reaction at room temperature, surpassing most previously reported Pd(II)/COF catalysts with respect to catalytic performance, preparation time, and synthetic ease. This microwave‐assistedin situmetal encapsulation strategy opens a facile and rapid avenue to construct metal/COF hybrids, which hold enormous potential in a multitude of applications including heterogeneous catalysis, sensing, and energy storage.more » « less
-
Abstract There are many applications for gold nanoparticles (AuNPs) due to their interesting optoelectronic properties such as tunable optical absorption and plasmonic resonance behavior. Although synthesis and stabilization of colloidal AuNPs are well established, new synthesis routes can lead to enhanced versatility of applications for AuNPs, particularly if the methods allow avoidance of solution processes or surfactants. Here, we introduce a plasma‐based synthesis of AuNPs, using a consumable gold wire and a radiofrequency power source. The AuNPs are monodisperse, with an average diameter of 4 nm. Although production yield is low, the narrow size distribution of the AuNPs and the avoidance of solution processing in this method are promising for future syntheses of metal NPs based on plasmas.more » « less
-
Microalgae Peptide-Stabilized Gold Nanoparticles as a Versatile Material for Biomedical ApplicationsMicroalgae peptides have many medical and industrial applications due to their functional properties. However, the rapid degradation of peptides not naturally present in biological samples represents a challenge. A strategy to increase microalgae peptide stability in biological samples is to use carriers to protect the active peptide and regulate its release. This study explores the use of gold nanoparticles (AuNPs) as carriers of the Chlorella microalgae peptide (VECYGPNRPQF). The potential of these peptide biomolecules as stabilizing agents to improve the colloidal stability of AuNPs in physiological environments is also discussed. Spectroscopic (UV-VIS, DLS) and Microscopic (TEM) analyses confirmed that the employed modification method produced spherical AuNPs by an average 15 nm diameter. Successful peptide capping of AuNPs was confirmed with TEM images and FTIR spectroscopy. The stability of the microalgae peptide increased when immobilized into the AuNPs surface, as confirmed by the observed thermal shifts in DSC and high zeta-potential values in the colloidal solution. By optimizing the synthesis of AuNPs and tracking the conferred chemical properties as AuNPs were modified with the peptide via various alternative methods, the synthesis of an effective peptide-based coating system for AuNPs and drug carriers was achieved. The microalgae peptide AuNPs showed lower ecotoxicity and better viability than the regular AuNPs.more » « less
