Self-Assembled Nanoreactors

Vriezema, Dennis M.; Aragones, M. Comellas; Elemans, Johannes A. A. W.; Cornelissen, Jeroen J. L. M.; Rowan, Alan E.; Nolte, Roeland J. M.

doi:10.1021/cr0300688

Cited by 1,427 publications

(1,008 citation statements)

References 355 publications

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“…To emulate this mode of catalysis, many research groups have designed synthetic hosts capable of binding and directing the reactivity of guest molecules. [5][6][7][8][9][10][11][12][13] Upon encapsulation in either a synthetic host or an enzyme active site, the environment surrounding a guest molecule drastically differs from that of the bulk solution. Steric constraints, functional group positioning, and sequestration from other molecules can enforce reactivity and selectivity that is impossible when simpler catalysts are employed.…”

Section: Introductionmentioning

confidence: 99%

“…Steric constraints, functional group positioning, and sequestration from other molecules can enforce reactivity and selectivity that is impossible when simpler catalysts are employed. 8,13 Early work using crown ethers, cryptands, and cyclodextrins demonstrated the ability of molecular hosts to bind guests and influence chemical reactivity. [14][15][16] The development of host-mediated reactivity demands the creation of larger and more complex synthetic hosts, which in turn requires timeconsuming multistep syntheses.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Aza Cope Rearrangement of Propargyl Enammonium Cations Catalyzed By a Self-Assembled “Nanozyme”

et al. 2008

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Aza Cope Rearrangement of Propargyl Enammonium Cations Catalyzed By a Self-Assembled “Nanozyme”

et al. 2008

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“…While the development of synthetic host-guest systems has not reached the level of enzyme specificity, the characteristics of each synthetic assembly, such as the size, shape, charge, and functional group availability, greatly influence the guest-binding characteristics and have led to remarkable and often unexpected reactivity. 9,[16][17][18][19][20][21][22][23] For example, the increased local concentration upon encapsulation of substrates for bimolecular reactions has been exploited for enhanced reactivity inside of synthetic hosts. By pre-organizing substrates, supramolecular assemblies are able to catalyze cycloadditions or pericyclic reactions such as Diels-Alder reactions.…”

Section: Introductionmentioning

confidence: 99%

Spin Equilibria in Monomeric Manganocenes: Solid-State Magnetic and EXAFS Studies

et al. 2009

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A water-soluble self-assembled supramolecular host molecule catalyzes the hydrolysis of orthoformates in basic solution. Comparison of the rate constants of the catalyzed and uncatalyzed reactions for hydrolysis displays rate accelerations of up to 3900 for tri-n-propyl orthoformate. Kinetic analysis shows that the mechanism of hydrolysis with the supramolecular host obeys the Michaelis-Menten model.Mechanistic studies, including 13 C-labeling experiments, revealed that the resting state of the catalytic system is the neutral substrate encapsulated in the host. Activation parameters for the k cat step of the reaction revealed that upon encapsulation in the assembly, the entropy of activation becomes more negative in contrast to the uncatalyzed reaction. Furthermore, solvent isotope effects reveal a normal k(H 2 O)/k(D 2 O) = 1.6, confirming that proton transfer is occurring in the transition state and is rate limiting in the catalyzed reaction. In comparison to the uncatalyzed reaction, which operates by an A-1 mechanism in which the decomposition of the protonated substrate is rate limiting, the encapsulated reaction proceeds through an A-S E 2 mechanism in which proton transfer from protonated water to the substrate is rate limiting.

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“…Not surprisingly, chemists have long been interested in generating "nanoreactors" to control chemical reactivity. 1,2 Nanoreactors prepared through either covalent construction or self-assembly have been reported. 3 For example, Rebek and co-workers functionalized resorcinarene-derived deep cavitands and used them to achieve molecular recognition and to enhance chemical reactivity.…”

mentioning

confidence: 99%

Catalyzing Methanolysis of Alkyl Halides in the Interior of an Amphiphilic Molecular Basket

2007

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A molecular basket with four cholate units assembled on a cone-shaped calix [4]arene assumed reversed micelle-like conformation in 5% methanol/carbon tetrachloride. The inwardly facing hydroxyl groups on the cholates concentrated the polar solvent from the mostly nonpolar mixture. Methanolysis of alkyl halides benefited from the concentrated pocket of methanol if the substrate was capable of entering the basket. Substrates that were too large or too hydrophobic to fit within the basket showed no rate acceleration. Substrates that were too large or too hydrophobic to fit within the basket showed no rate acceleration.

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Self-Assembled Nanoreactors

Cited by 1,427 publications

References 355 publications

Aza Cope Rearrangement of Propargyl Enammonium Cations Catalyzed By a Self-Assembled “Nanozyme”

Aza Cope Rearrangement of Propargyl Enammonium Cations Catalyzed By a Self-Assembled “Nanozyme”

Spin Equilibria in Monomeric Manganocenes: Solid-State Magnetic and EXAFS Studies

Catalyzing Methanolysis of Alkyl Halides in the Interior of an Amphiphilic Molecular Basket

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