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Voort, Pascal Van Der; Mathieu, M; Vansant, E. F.; Rao, S.N.R.; White, Mark G.

doi:10.1023/a:1009642507133

Cited by 17 publications

(16 citation statements)

References 23 publications

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“…These bands are assigned to δ CH , ν C−C−Cs , and ν COring , respectively, resembling those characterizing Hacac adsorbed on the zeolite. 11,12 Thus, the IR data indicate that acac ligands were dissociated from the iridium as a result of the reaction of the precursor with the acidic OH groups of the zeolite, forming chemisorbed iridium complexes.…”

Section: ■ Resultsmentioning

confidence: 99%

Site-Isolated Molecular Iridium Complex Catalyst Supported in the 1-Dimensional Channels of Zeolite HSSZ-53: Characterization by Spectroscopy and Aberration-Corrected Scanning Transmission Electron Microscopy

Lu¹,

Aydin²,

Liang

et al. 2012

ACS Catal.

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Zeolite HSSZ-53, which has 1-dimensional channels with 14-ring extra-large pores, was used as a support for a molecular iridium complex synthesized from Ir(C 2 H 4 ) 2 (C 5 H 7 O 2 ) and characterized with infrared (IR) and extended X-ray absorption fine structure (EXAFS) spectroscopies and atomic-resolution aberration-corrected scanning transmission electron microscopy (STEM). The spectra show that Ir(C 2 H 4 ) 2 (C 5 H 7 O 2 ) reacted readily with the bridging OH groups of the zeolite, leading to the removal of C 5 H 7 O 2 ligands and the formation of mononuclear Ir(C 2 H 4 ) 2 complexes bonded to the zeolite by Ir−O bonds at the framework aluminum sites. STEM images confirm the spectra, showing site-isolated iridium centers within the zeolite channels, with no evidence of iridium clusters. The samples constitute a highly uniform, well-defined array of essentially molecular catalytic species in a highly uniform, confined environment, allowing precise investigations of the chemistry of the iridium complex in the absence of solvents. IR spectra show that the supported Ir(C 2 H 4 ) 2 complexes were converted to Ir(C 2 H 5 ) 2 , Ir(CO) 2 , Ir(CO)(C 2 H 4 ), and Ir(CO)(C 2 H 4 ) 2 as various mixtures of H 2 , CO, and C 2 H 4 reacted with the sample. The sample was tested as a catalyst for ethylene hydrogenation and for H−D exchange in the reaction of H 2 + D 2 . The data, combined with results reported for isostructural iridium complexes bonded to zeolite HY and to MgO, demonstrate how the catalytic activity can be tuned by choice of the support, with the support being characterized as a ligand with electron-donating or electronwithdrawing properties. The results demonstrate that the rate of ethylene hydrogenation catalyzed by the supported iridium complexes is limited by H 2 activation when the iridium is electron rich (on the MgO support), whereas the rate-limiting step is C 2 H 4 adsorption when the iridium is electron deficient (on either zeolite support).

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Section: ■ Resultsmentioning

confidence: 99%

Site-Isolated Molecular Iridium Complex Catalyst Supported in the 1-Dimensional Channels of Zeolite HSSZ-53: Characterization by Spectroscopy and Aberration-Corrected Scanning Transmission Electron Microscopy

Lu¹,

Aydin²,

Liang

et al. 2012

ACS Catal.

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show abstract

“…Crystalline CuO and Cr 2 O 3 phases emerged when the hydrated chlorides replaced the corresponding hydrated nitrates with the same loading amount, but cupric acetate hydrate did have such effect. In liquid-solid or gas-solid systems, the precursor is anchored to the hydroxyl groups of the support by a hydrogen-bonding or a ligand exchange mechanism [7,8], where anions bridged the hydroxyls of support and the cation of precursor salts. In solid-solid systems, anions mediate the interaction between the surface hydroxyl of support and cations in the precursor.…”

Section: Article In Pressmentioning

confidence: 99%

“…Moreover, organic precursor species are more complex and expensive in this procedure [4,5]. The other two less popular methods are the solid-state exchange and the loading via the gas phase by a volatile precursor and subsequent calcinations [6][7][8]. Although solid-state exchange has been widely studied in the synthesis of modified zeolites [9], few solid-state studies are devoted to the supported mesoporous materials.…”

Section: Introductionmentioning

confidence: 99%

Surface functionalization of SBA-15 by the solvent-free method

Wang

Zhu

2004

Journal of Solid State Chemistry

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“…Van der Voort et al [261][262][263] prepared vanadium oxide species in the mesoporous material MCM-48 by reacting the support with gaseous vanadyl acetylacetonate [VO(acac) 2 ]. The vapor deposition was carried out in a vacuum reactor (see Fig.…”

Section: Chemical Vapor Deposition Of Miscellaneous Compoundsmentioning

confidence: 99%

“…The average pore diameter and the total pore volume of the MCM-48 host decreased after loading with the bulky vanadyl acetylacetonate [261][262][263]. On calcination, both values increased again, and the BET surface area was restored to 80% of its original value.…”

Section: Chemical Vapor Deposition Of Miscellaneous Compoundsmentioning

confidence: 99%