<i>N</i>-Heterocyclic Carbene-Based Conducting Polymer–Gold Nanoparticle Hybrids and Their Catalytic Application

Song, Sun Gu; Satheeshkumar, Chinnadurai; Park, Jiyoung; Ahn, Jaeseop; Premkumar, Thathan; Lee, Yun-Mi; Song, Changsik

doi:10.1021/ma501817n

Cited by 59 publications

(51 citation statements)

References 38 publications

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“…8e,g−j Despite the broad scope of known gold-catalyzed transformations 9 and the growing body of work on NHC-Au surface chemistry, 5,6b,10 catalysis by NHC-ligated Au NPs has been scarcely explored, and to our knowledge, only been applied to hydrogenation chemistry or electrochemical CO 2 reduction. 8k,l, 11 A main challenge has been to systematically vary the ligand structure without perturbing Au NP stability to Au complex leaching and/or NP aggregation. Work in our laboratories on supported dendrimer encapsulated Au NPs 1d−f provided a platform for overcoming this challenge.…”

Section: ■ Introductionmentioning

confidence: 99%

Supported Au Nanoparticles with N-Heterocyclic Carbene Ligands as Active and Stable Heterogeneous Catalysts for Lactonization

et al. 2018

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Attachment of N-heterocyclic carbenes (NHCs) on the surface of metal nanoparticle (NP) catalysts permits fine-tuning of catalytic activity and product selectivity. Yet, NHC-coated Au NPs have been seldom used in catalysis beyond hydrogenation chemistry. One challenge in this field has been to develop a platform that permits arbitrary ligand modification without having to compromise NP stability toward aggregation or leaching. Herein, we exploit the strategy of supported dendrimer-encapsulated metal clusters (DEMCs) to achieve aggregation-stable yet active heterogeneous Au NP catalysts with NHC ligands. Dendrimers function as aggregation-inhibitors during the NP synthesis, and NHCs, well-known for their strong attachment to the gold surface, provide a handle to modify the stereochemistry, stereoelectronics, and chemical functionality of the NP surface. Indeed, compared to "ligandless" Au NPs which are virtually inactive below 80 °C, the NHC-ligated Au NP catalysts enable a model lactonization reaction to proceed at 20 °C on the same time scale (hours). Based on Eyring analysis, proto-deauration is the turnover-limiting step accelerated by the NHC ligands. Furthermore, the use of chiral NHCs led to asymmetric induction (up to 16% enantiomeric excess) in the lactonization transformations, which demonstrates the potential of supported DEMCs with ancillary ligands in enantioselective catalysis.

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Section: ■ Introductionmentioning

confidence: 99%

Supported Au Nanoparticles with N-Heterocyclic Carbene Ligands as Active and Stable Heterogeneous Catalysts for Lactonization

et al. 2018

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“…Even though a lot of examples are known for NHC-transition metal complexes as the building block into the backbone of polymeric materials, the complete study of the coinage metals in the conducting polymer material with a combination of NHC building block still not investigated. 28 With the widespread and increasing interest in NHC materials, there is a growing realization that the presence of metal centers in CPs can result in new and valuable properties. 26 NHCs with Ag and Au containing polymer thin films revealed that highly reversible electrochromic phenomena have been reported by Cowley and coworkers.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and electronic properties of N-heterocyclic carbene-containing conducting polymers with coinage metals

et al. 2015

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The recent development of functional materials based on conducting metal-containing polymer, we designed and synthesized a series of bithiophene based N-heterocyclic carbene (NHC)-conducting polymer using coinage metals (Cu, Ag, and Au). Absorption spectroscopy, NMR spectroscopy, cyclic voltammetry, and X-ray photoelectron spectroscopy (XPS) were used to analyze the monomers and polymer thin films. The peak current of the electrodeposited film on the Ptbutton electrodes increased proportionally with a scan rate exhibited the stability of polymer thin films. Remarkably, in the electrochemical studies of the coinage metals complexes, the redox potential of the Cu + /Cu 2+ perfectly matched with quaterthiophene moieties of the polymer backbone redox wave. However, the redox potential of Ag/Ag + did not matched with the redox potential of the polymer backbone. During the oxidation process in the spectroelectrochemical studies, conducting coinage metallopolymers exhibited a drastic color change from orange (reduced form) to dark green (oxidized form) and can be envisioned in the application of electrochromic materials.

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“…Recent Advances in the Schiff Bases and NHCs as Ligands in the Cross-Coupling Reactions Song and co-workers [157] reported hybrid nanocomposites of NHC-functionalized conducting polymers with gold NPs (AuNPs) prepared by concurrent disproportionation and oxidative coupling in 89% yield as shown in Scheme 120. The NHC group played a pivotal role in the dispersion of AuNPs.…”

Section: April 2019mentioning

confidence: 99%

Recent Advances in the Schiff Bases and N‐Heterocyclic Carbenes as Ligands in the Cross‐Coupling Reactions: A Comprehensive Review

Kumar

2019

Journal of Heterocyclic Chem

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Cross‐coupling reactions, namely, the Suzuki–Miyaura, Heck, Sonogashira, Hiyama, Negishi, Kumada, and Hartwig–Buchwald, are the most powerful approaches in the formation of C–C, C–N, C–O, and C–S bonds for the complex organic scaffolds in drugs, natural products, organic materials, and fine chemicals. The nitrogen‐based ligands have upper hands in these reactions because they are air stable, inexpensive, and easier to handle than the phosphorous counterparts. In this perspective, Schiff bases and N‐heterocyclic carbenes have been explored extensively in terms of novel design and preparation as ligands in the coupling reactions. Facile recovery and reusability of these ligands make them eco‐friendly and economical. A comprehensive outline on the progress in Schiff bases–metal complexes and NHC–metal complexes that mediated cross‐coupling reactions with recent examples highlighted is reported (160 references).

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N-Heterocyclic Carbene-Based Conducting Polymer–Gold Nanoparticle Hybrids and Their Catalytic Application

Cited by 59 publications

References 38 publications

Supported Au Nanoparticles with N-Heterocyclic Carbene Ligands as Active and Stable Heterogeneous Catalysts for Lactonization

Supported Au Nanoparticles with N-Heterocyclic Carbene Ligands as Active and Stable Heterogeneous Catalysts for Lactonization

Synthesis and electronic properties of N-heterocyclic carbene-containing conducting polymers with coinage metals

Recent Advances in the Schiff Bases and N‐Heterocyclic Carbenes as Ligands in the Cross‐Coupling Reactions: A Comprehensive Review

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