Correlated bifunctionality in heterogeneous catalysts: selective tethering of cinchonidine next to supported Pt nanoparticles

Hong, Junghyun; Lee, Ilkeun; Zaera, Francisco

doi:10.1039/c4cy00844h

Cited by 20 publications

(25 citation statements)

References 70 publications

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“…This idea has been tested by others in the past [117][118][119], but here a new methodology was advanced to perform the cinchonidine tethering in a correlated fashion, that is, selectively on sites adjacent to the Pt nanoparticles, in order to enhance the performance of the catalyst (Fig. 12) [120]. The protocol relies on the selective strong adsorption of the cinchona alkaloid on the platinum surface, the same interaction responsible for the chiral modification: a cinchonidine molecule to which a propyltriethoxysilane moiety has been added is first exposed to the catalyst, the excess is then washed away with pure solvent, and the click chemistry that links the chiral modifier to the surface of the silica surface is finally triggered via thermal activation.…”

Section: Studies With More Realistic Catalyst Modelsmentioning

confidence: 99%

Surface Chemistry for Enantioselective Catalysis

2014

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A Perspective is offered on the lessons learned from surface-science studies on enantioselective chemistry on solid surfaces performed by the author's groups. Our emphasis is on studies on model systems, mainly metal single-crystal surfaces under controlled environments, but extension of such research to more realistic samples relevant to heterogeneous catalysis is also briefly discussed. Enantioselective chemistry on surfaces is here divided into three guiding modalities, depending on the underlying mechanism. First, enantioselective chemistry resulting from the use of intrinsically chiral surfaces, which can be made from achiral solids such as metals by exposing the appropriate planes, is discussed. Next, the imparting of enantioselectivity to achiral surfaces by modifying them with adsorbates is classified in terms of two operating mechanisms: first, via the formation of supramolecular surface ensembles with chiral adsorption sites, and second, by relying on the effect of the local chiral environment intrinsically provided by the chiral modifiers through a one-to-one interaction between the modifier and the reactant. A discussion is then provided on studies with more complex samples involving metal nanoparticles and highsurface-area porous oxides. Finally, the present state of our understanding of enantioselective surface chemistry and the prognosis for the future are provided.

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Section: Studies With More Realistic Catalyst Modelsmentioning

confidence: 99%

Surface Chemistry for Enantioselective Catalysis

2014

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“…[20][21][22][23][24][25][26][27][28][29][30] However, among the numerous reports, only a few studies are available that focus on recycling of the chiral catalyst and in which the enantiomeric excess (ee) values still need improvement. [30][31][32][33][34] Therefore, with the purpose of achieving high ee values and recycling of the chiral catalyst, the asymmetric hydrogenation of methyl benzoylformate (MBF) was investigated as a model substrate and the reaction conditions were systematically explored (Table 2). First, the CIL TPT-MS /Pt molar ratio was investigated (Table 2, entries 1-4).…”

Section: The Asymmetric Hydrogenation Of αKetoesters Catalyzed By the Chiral Nano-pt Catalystmentioning

confidence: 99%

A novel thermoregulated phase-transfer catalysis system for chiral nano-Pt-catalyzed asymmetric hydrogenation

Chen

Wang

2021

Journal of Chemical Research

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The chiral ionic liquid CILTPT-MS [CH3(OCH2CH2)16CD]+[CH3SO3]− (CD = cinchonidine) is found to exhibit cloud point character. Due to this cloud point character, a CILTPT-MS-stabilized chiral nano-Pt catalyst is prepared and utilized to realize transfer in a H2O–1-pentanol biphasic system by simply changing the temperature. Therefore, a fluorine-free, thermoregulated phase-transfer catalysis system is developed and applied to the asymmetric hydrogenation of α-ketoesters with enantiomeric excess of >99% and excellent conversion. In addition, the chiral nano-Pt catalyst can be easily separated and reused efficiently.

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“…The supporting materials should be thermally, chemically and mechanically stable during the reaction process. In these sequences, inorganic oxide such as silica, zeolite, Al 2 O 3 , ZrO 2 , ZnO, clay and more recently carbon materials are using as a support. These materials have been proved best supporting materials, but required chemical activation 2c and high temperature for strong metal‐oxide interaction .…”

Section: Introductionmentioning

confidence: 99%

Platinum functionalized Chiral Polyamides: Efficient Heterogeneous Catalyst for Solvent Free Asymmetric Hydrogenation of Ethyl 2‐oxo‐4‐phenylbutanoate

Sharma

2017

ChemistrySelect

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The present study highlights platinum nanoparticles incorporated chiral polyamide for asymmetric hydrogenation of carbonyl group. Chiral polyamides are synthesized from chiral monomers, camphoric dichloride and achiral diamine monomers by interfacial condensation reaction. This chiral polyamide supports have helical structure with molecular chirality. The polyamide helices provide chiral environment to platinum nanoparticles that transfer to substrate during catalytic hydrogenation. The chemical and optical selectivity increases with dispersion of platinum nanoparticles on chiral polyamide which act like isolated single atomic catalytic centers. The distribution of nanoparticles depends on spacer used in amine monomer unit. The catalytically active single atom nanoparticles have preferentially Pt (111) planes and exhibit excellent selectivity up to 10 cycles (TOF > 5400 h À1 and > 99.9% ee) in asymmetric hydrogenation reaction of ethyl 2-oxo-4-phenylbutanoate under solvent free condition.[a] P.

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Correlated bifunctionality in heterogeneous catalysts: selective tethering of cinchonidine next to supported Pt nanoparticles

Abstract: A strategy has been devised to add molecular functionality to heterogeneous catalysts in a spatially correlated fashion.

Cited by 20 publications

References 70 publications

Surface Chemistry for Enantioselective Catalysis

Surface Chemistry for Enantioselective Catalysis

A novel thermoregulated phase-transfer catalysis system for chiral nano-Pt-catalyzed asymmetric hydrogenation

Platinum functionalized Chiral Polyamides: Efficient Heterogeneous Catalyst for Solvent Free Asymmetric Hydrogenation of Ethyl 2‐oxo‐4‐phenylbutanoate

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