Enhancing Heterogeneous Catalysis through Cooperative Hybrid Organic–Inorganic Interfaces

Notestein, Justin M.; Katz, Alexander

doi:10.1002/chem.200501152

Cited by 237 publications

(160 citation statements)

References 66 publications

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“…The weaklyacidic silanol groups can form hydrogen bonds to reactants or transition states, leading to cooperative catalysis with surface organic groups. Cooperativity between organic functional groups and inorganic supports has been reviewed by Notestein and Katz, 21 and will not be discussed in great detail, but a few recent advances are worth noting.…”

Section: Cooperativity With the Silica Matrixmentioning

confidence: 99%

Cooperative catalysis by silica-supported organic functional groups

2008

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Hybrid inorganic-organic materials comprising organic functional groups tethered from silica surfaces are versatile, heterogeneous catalysts. Recent advances have led to the preparation of silica materials containing multiple, different functional groups that can show cooperative catalysis; that is, these functional groups can act together to provide catalytic activity and selectivity superior to what can be obtained from either monofunctional materials or homogeneous catalysts. This tutorial review discusses cooperative catalysis of silica-based catalytic materials, focusing on the cooperative action of acid-base, acid-thiol, amine-urea, and imidazole-alcohol-carboxylate groups. Particular attention is given to the effect of the spatial arrangement of these organic groups and recent developments in the spatial organization of multiple groups on the silica surface.

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Section: Cooperativity With the Silica Matrixmentioning

confidence: 99%

Cooperative catalysis by silica-supported organic functional groups

2008

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“…116 There are several types of metal-complex attachment techniques: coordination of metal-complex precursors to immobilized ligands on organic polymers, 1721 coordination of metal-complex precursors to functional ligands bound to oxide surfaces, 2,4,2225 intercalation into clay materials, 26 ion exchange into porous materials such as zeolite and mesoporous silica, 27 and direct attachment of metal-complex precursor onto oxide surfaces. 3,6,11,28,29 The interfacial attachment between a metal complex and an oxide surface can produce unique metal coordination different from the original metal-complex precursor. For example, SiOH is reacted with a M(CH 3 ) complex and a M(OSi) complex is produced, releasing CH 4 .…”

Section: Surface-mediated Design Of Catalytically Activementioning

confidence: 99%

“…A chemical bond between a metal-complex precursor and a support surface modifies the reactivity of the supported metal complex, resulting in novel catalytic activity the precursor complex does not exhibit. 3,6,11,28,29 Traditional ion-exchange on zeolites and intercalation to clay materials are also typical ways to introduce metal species onto solid supports although the valences and types of metal precursors are restricted. 4 Direct reactions of metal-complex precursors and hydroxy groups on oxide surfaces create novel metal-coordination structures, and many important factors for selective catalysis can be controlled at the interface, such as electronic properties and coordination sphere of the attached metal center, geometry around the active metal center, and dispersion and stability of the attached metal sites.…”

Section: Surface-mediated Design Of Catalytically Activementioning

confidence: 99%

Surface-Mediated Design and Catalytic Properties of Active Metal Complexes for Advanced Catalysis Creation

Tada¹

2010

Bulletin of the Chemical Society of Japan

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Molecular-scale design of catalytically active structures at oxide surfaces is highlighted, focusing on our recent challenges for selective heterogeneous catalysis. We found novel structural transformations of supported metal complexes on oxide surfaces and achieved unique selective catalysis for various chemical syntheses. In this account, the advanced design of supported metal-complex catalysts on oxide surfaces and the in situ characterization of their structural kinetics, which means kinetics of structural changes of catalysts themselves, under catalyst-working conditions are reviewed. Surface-Mediated Design of Catalytically ActiveStructures for Selective Catalysis 1.1 Introduction: Metal-Complex Attaching on Oxide Surfaces. Heterogeneous solid catalysts have been widely utilized for the industrial production of many synthetic chemicals. The advantages of heterogeneous catalysts are not only the separation of catalysts and products from reaction media but also their high durability and catalytic activities resulting from the unique structures of catalytically active sites at solid surfaces. Relationships among the metal structures, organized environment, and the catalytic properties of surface species tell us the nature of catalysis and new strategy for rational design of heterogeneous catalysts.Metal-complex attachment to oxide surfaces is a practical way to produce molecularly regulated structures of active metal species on oxide surfaces, and subsequent structural transformation in a controllable manner often provides unique regulated metal structures active for selective catalytic reactions. 116 There are several types of metal-complex attachment techniques: coordination of metal-complex precursors to immobilized ligands on organic polymers, 1721 coordination of metal-complex precursors to functional ligands bound to oxide surfaces, 2,4,2225 intercalation into clay materials, 26 ion exchange into porous materials such as zeolite and mesoporous silica, 27 and direct attachment of metal-complex precursor onto oxide surfaces. 3,6,11,28,29 The interfacial attachment between a metal complex and an oxide surface can produce unique metal coordination different from the original metal-complex precursor. For example, SiOH is reacted with a M(CH 3 ) complex and a M(OSi) complex is produced, releasing CH 4 . A chemical bond between a metal-complex precursor and a support surface modifies the reactivity of the supported metal complex, resulting in novel catalytic activity the precursor complex does not exhibit. 3,6,11,28,29 Traditional ion-exchange on zeolites and intercalation to clay materials are also typical ways to introduce metal species onto solid supports although the valences and types of metal precursors are restricted. 4 Direct reactions of metal-complex precursors and hydroxy groups on oxide surfaces create novel metal-coordination structures, and many important factors for selective catalysis can be controlled at the interface, such as electronic properties and coordination sphere of the attached metal...

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“…[1] Remarkably, many enzymes combine two antagonistic catalytic functions, such as acid and base functions. [2] Attracted by this challenge, several groups synthesized homogeneous catalysts that can successfully combine chemically hostile functions.…”

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confidence: 99%