Surface-grafted metal oxide clusters and metal carbonyl clusters in zeolite micropores; XAFS/FTIR/TPD characterization and catalytic behavior

Ichikawa, Masaru; Pan, Wei; Imada, Yasunori; Yamaguchi, Masatugu; Isobe, Kiyoshi; Shido, Takafumi

doi:10.1016/1381-1169(95)00226-x

Cited by 29 publications

(18 citation statements)

References 28 publications

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“…This development reflects not only academic interest in such compounds, being a logical development of POM chemistry in general, but is also driven by the well-known catalytic properties of noble-metal complexes. 5 This point of view has a good endorsement in the chemistry of organometallic/oxide complexes of vanadium or mixed tungsten-vanadium or niobium-tungsten POM complexes.…”

Section: Introductionmentioning

confidence: 96%

Grafting {Cp*Rh}²⁺ on the surface of Nb and Ta Lindqvist-type POM

et al. 2015

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New hybrid POM based on Lindqvist-type polyoxometalates [M6O19](8-) (M = Nb, Ta) and organometallic fragment {Cp*Rh}(2+) have been isolated and characterized. X-ray quality crystals of K4[(Cp*Rh)2Nb6O19]·20H2O () and Cs4[(Cp*Rh)2Ta6O19]·18H2O () were obtained from solutions with {Cp*Rh} : [M6O19](8-) stoichiometry 2 : 1. The solution behavior of the hybrid polyoxoanions was studied with ESI-MS and (1)H DOSY NMR. Amongst the poorly investigated chemistry of polyoxotantalates, complex is the first complex bearing a grafted organometallic fragment. The formation of 1 : 1 complexes was detected by ESI-MS techniques.

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Section: Introductionmentioning

confidence: 96%

Grafting {Cp*Rh}²⁺ on the surface of Nb and Ta Lindqvist-type POM

et al. 2015

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“…Tetravanadate-supported organometallic complexes are further supported on SiO 2 to act as a catalyst for the selective oxidation of propene to acetone [54,55]. …”

Section: Tetravanadate-supported Metal Complexesmentioning

confidence: 99%

Hetero and lacunary polyoxovanadate chemistry: Synthesis, reactivity and structural aspects

Hayashi

2011

Coordination Chemistry Reviews

214

126

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Many synthetic methods for heteropolyoxovanadates and lacunary polyoxovanadates have been developed in recent years. We outline various approaches used to produce new polyoxovanadate species, including heterometal-incorporated complexes of tetravanadates, hexavanadates, decavanadates and dodecavanadates. In particular, three types of synthetic routes are explored; based on i) coordination of metavanadate species to transition metal cations, ii) oxidation of reduced polyoxovanadates, and iii) template synthesis. Metavanadate species can coordinate to metal cations as inorganic macrocyclic ligands to form heteropolyoxovanadates. The incorporation of a heterometal cation into decavanadates has also been reported. The oxidation reaction of reduced polyoxovanadates provides a new route to the formation of the lacunary polyoxovanadates, which can serve as inorganic host molecules. Dodecavanadates are bowl-type molecules of particular structural interest; a chloride anion can be incorporated into the bowl through a template synthesis. Structural transformations between these dodecavanadate species and alkoxopolyoxovanadates are also described.

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“…Similarly, [Rh 4 Fe 2 (CO) 16 ] 2− entrapped in zeolite NaY was prepared by the reaction of Fe 2 (CO) 9 and immobilized Rh(CO) 2 species formed in the zeolite cages from adsorption of Rh 4 (CO) 12 [66]. The decarbonylation of zeolite-supported HRuCo 3 (CO) 12 and [Rh 4 Fe 2 (CO) 16 ] 2− led to the formation of highly dispersed Ru-Co and Rh-Fe clusters of less than 10 Å in average diameter.…”

Section: Synthesismentioning

confidence: 97%

“…For example, HRuCo 3 (CO) 12 was formed by reductive carbonylation of Ru 3+ exchange ions on zeolite NaY or zeolite NaX containing Co 2 (CO) 8 , that had been previously adsorbed, and treated with a mixture of CO and H 2 at 323 K [65]. Similarly, [Rh 4 Fe 2 (CO) 16 ] 2− entrapped in zeolite NaY was prepared by the reaction of Fe 2 (CO) 9 and immobilized Rh(CO) 2 species formed in the zeolite cages from adsorption of Rh 4 (CO) 12 [66]. The decarbonylation of zeolite-supported HRuCo 3 (CO) 12 and [Rh 4 Fe 2 (CO) 16 ] 2− led to the formation of highly dispersed Ru-Co and Rh-Fe clusters of less than 10 Å in average diameter.…”

Section: Synthesismentioning

confidence: 98%

“…The metal frame of catalysts prepared similarly on weakly basic MgO was also essentially unchanged from that of the precursor H 3 Re 3 (CO) 12 , but on strongly basic MgO, the precursor was deprotonated [41]. In another example, Gates and coworkers reported that metal carbonyl clusters [e.g., Ir 4 (CO) 12 , Ir 6 (CO) 16 , and Rh 6 (CO) 16 ] are adsorbed intact from n-pentane onto essentially neutral supports such as g-Al 2 O 3 [42] or TiO 2 [43] 12 and Ir 6 (CO) 16 , respectively). These examples clearly show the crucial role of the support in the stabilization of the metal clusters -a property that could be tuned in order to selectively control catalytic performance of active species.…”

Section: Synthesismentioning

confidence: 98%

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Well-Defined Metallic and Bimetallic Clusters Supported on Oxides and Zeolites

Guzmán

2009

Model Systems in Catalysis

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Immobilized metallic and bimetallic complexes and clusters on oxide or zeolite supports made from well-defined molecular organometallic precursors have drawn wide attention because of their novel size-dependent properties and their potential applications for catalysis. It is speculated that nearly molecular supported catalysts may combine the high activity and selectivity of homogenous catalysts with the ease of separation and robustness of operation of heterogeneous catalysts. This chapter is a review of the synthesis and physical characterization of metallic and bimetallic complexes and clusters supported on metal oxides and zeolites prepared from organometallic precursors of well-defined molecularity and stoichiometry. IntroductionRational design of catalysts guided by fundamental principles correlating composition, structure, and ligand environment with catalyst activity and selectivity has been a longstanding goal in the field of catalysis [1, 2]. Several approaches have been pursued to identify the nature of the active centers, reaction mechanisms, and the kinetics of catalytic processes, including experimental and theoretical investigations of model systems and industrial catalysts. Nevertheless, our understanding of the relationship between active center properties and catalytic performance is far from complete. Even the most thoroughly characterized supported metal catalysts prepared conventionally from salt precursors are less than well understood, because of the limitations of both the samples (nonuniformity of the metal entities) and standard characterization methods, such as N 2 -adsorption, temperature programmed reduction (TPR), etc. In the last few decades, researchers have worked toward the development and use of simple models of supported

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Surface-grafted metal oxide clusters and metal carbonyl clusters in zeolite micropores; XAFS/FTIR/TPD characterization and catalytic behavior

Cited by 29 publications

References 28 publications

Grafting {Cp*Rh}²⁺ on the surface of Nb and Ta Lindqvist-type POM

Grafting {Cp*Rh}²⁺ on the surface of Nb and Ta Lindqvist-type POM

Hetero and lacunary polyoxovanadate chemistry: Synthesis, reactivity and structural aspects

Well-Defined Metallic and Bimetallic Clusters Supported on Oxides and Zeolites

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Surface-grafted metal oxide clusters and metal carbonyl clusters in zeolite micropores; XAFS/FTIR/TPD characterization and catalytic behavior

Cited by 29 publications

References 28 publications

Grafting {Cp*Rh}2+ on the surface of Nb and Ta Lindqvist-type POM

Grafting {Cp*Rh}2+ on the surface of Nb and Ta Lindqvist-type POM

Hetero and lacunary polyoxovanadate chemistry: Synthesis, reactivity and structural aspects

Well-Defined Metallic and Bimetallic Clusters Supported on Oxides and Zeolites

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Product

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Grafting {Cp*Rh}²⁺ on the surface of Nb and Ta Lindqvist-type POM

Grafting {Cp*Rh}²⁺ on the surface of Nb and Ta Lindqvist-type POM