Investigation of activity, stability, and degradation mechanism of surface-supported Pd-PEPPSI complexes for Suzuki-Miyaura coupling

Marquard, Angela N.; Slaymaker, Laura E.; Hamers, Robert J.; Goldsmith, Randall H.

doi:10.1016/j.molcata.2016.12.001

Cited by 11 publications

(6 citation statements)

References 59 publications

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“…Under cross-coupling reaction conditions the catalyst resting state is a Pd(0) species. Aggregation involving several Pd(0) centers can occur during the reaction, which then form palladium nanoparticles that precipitate out of solution to form palladium black [ 167 ]. Metals can also be loaded onto the materials using impregnation methods [ 168 ], and photocatalytic deposition [ 2 ].…”

Section: Interface Between Polymer and Metal Co-catalystmentioning

confidence: 99%

Impact of Interfaces, and Nanostructure on the Performance of Conjugated Polymer Photocatalysts for Hydrogen Production from Water

2022

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The direct conversion of sunlight into hydrogen through water splitting, and by converting carbon dioxide into useful chemical building blocks and fuels, has been an active area of research since early reports in the 1970s. Most of the semiconductors that drive these photocatalytic processes have been inorganic semiconductors, but since the first report of carbon nitride organic semiconductors have also been considered. Conjugated materials have been relatively extensively studied as photocatalysts for solar fuels generation over the last 5 years due to the synthetic control over composition and properties. The understanding of materials’ properties, its impact on performance and underlying factors is still in its infancy. Here, we focus on the impact of interfaces, and nanostructure on fundamental processes which significantly contribute to performance in these organic photocatalysts. In particular, we focus on presenting explicit examples in understanding the interface of polymer photocatalysts with water and how it affects performance. Wetting has been shown to be a clear factor and we present strategies for increased wettability in conjugated polymer photocatalysts through modifications of the material. Furthermore, the limited exciton diffusion length in organic polymers has also been identified to affect the performance of these materials. Addressing this, we also discuss how increased internal and external surface areas increase the activity of organic polymer photocatalysts for hydrogen production from water.

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Section: Interface Between Polymer and Metal Co-catalystmentioning

confidence: 99%

Impact of Interfaces, and Nanostructure on the Performance of Conjugated Polymer Photocatalysts for Hydrogen Production from Water

2022

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“…Various other silica-supported Pd complexes have been used for cross-coupling reactions. Please see references − regarding recent examples of Heck, Suzuki–Miyaura, Negishi, and Sonogashira reactions.…”

Section: Isolated Metal Complex For Enhanced Catalysismentioning

confidence: 99%

Enhanced Catalysis Based on the Surface Environment of the Silica-Supported Metal Complex

et al. 2021

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Silica-supported metal complex catalysts have been developed and used for organic transformations. The surface environment around the supported metal complex enhances the catalysis based on a unique surface effect. The design of the linker ligand structure induces the formation of a highly reactive, coordinatively unsaturated metal complex on the silica surface because of the isolated environment. In contrast to the site-isolation effect, the accumulated metal complexes and cocatalysts on the same surface facilitate the acceleration of the catalytic reaction by concerted catalysis. The immobilization of multiactive sites also promotes the tandem catalysis and development of complex products from simple molecules through successive reactions. Surface silanol species originating from the silica support also participate in the catalysis. The control of the immobilization density/location of metal complex/coimmobilized functionality/surface silanol is a key factor for the achievement of site-isolation/concerted catalysis. The direct interaction between the metal complex and coimmobilized functionality facilitates the formation of unique reactive species. The confinement effect of the pore structure of the support enhances the accumulation of active species in mesopores, which boosts the reaction rate, and slightly changes the ligand conformation, which increases the enantioselectivity. The direct support electronic effect is also one of the key factors affecting the surface organometallic chemistry (SOMC) and photooxidation of linker metal complexes. These acceleration effects were detected in both supported homogeneous catalysis and SOMC. Not only the local structure of the metal complex and its ligand but also the surface environment play the most important roles in enhancing the catalysis. In this Review, representative examples of silica-supported metal complexes whose catalysis is significantly enhanced by their surface long-range environment are summarized. The contributions of recent developments of spectroscopic techniques, including DNP-enhanced solid-state NMR and XAFS, which support the evaluation of such long-range interactions, are also discussed. The surface design of the silica-supported metal complex facilitates highly active, selective, and durable catalysis.

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“…15–35 The formation of palladium black (hereafter ‘Pd black’, a term used colloquially to refer to the black precipitate of elemental Pd, formed via decomposition of various Pd complexes) is notorious for decreasing available active catalyst for the intended chemistry, complicating reaction work-up, and leading to expensive waste. 19,36 Indeed, Pd black is known to affect Suzuki–Miyaura and Negishi cross-coupling, 37 C–H arylation, 16 heterogeneous catalyst functionalisation, 30 homogeneous catalyst ligand design, 24 alkene carbonylation, 35 arene homocoupling, 32 Heck reactions, 33 metal scavenging and recycling, 19,36 aerobic alcohol oxidation, 22 tetrahydrofuran synthesis, 21 arene allylation, 23 homo- and co-polymerisation of ethylene, 38 and Miyaura borylation. 25…”

Section: Introductionmentioning

confidence: 99%

Computer vision for non-contact monitoring of catalyst degradation and product formation kinetics

et al. 2023

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Investigation of activity, stability, and degradation mechanism of surface-supported Pd-PEPPSI complexes for Suzuki-Miyaura coupling

Cited by 11 publications

References 59 publications

Impact of Interfaces, and Nanostructure on the Performance of Conjugated Polymer Photocatalysts for Hydrogen Production from Water

Impact of Interfaces, and Nanostructure on the Performance of Conjugated Polymer Photocatalysts for Hydrogen Production from Water

Enhanced Catalysis Based on the Surface Environment of the Silica-Supported Metal Complex

Computer vision for non-contact monitoring of catalyst degradation and product formation kinetics

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