Non-covalently dendronized flavins as organocatalysts for aerobic reduction of olefins

Imada, Yasushi; Kugimiya, Yudai; Iwata, Shotaro; Komiya, Naruyoshi

doi:10.1016/j.tet.2013.07.082

Cited by 15 publications

(6 citation statements)

References 39 publications

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“…Effect of H‐bonding additive 3 : The results strongly suggest that the significant red‐shift in the fluorescent chromism of 1 a with an increase in concentration, a decrease in temperature, and the variation of the solvent is attributed to an increase in donor‐acceptor interactions of 1 a units in the aggregates, which changes the dimensionality and the degree of aggregation based on H‐bonding and π‐stacking interactions of 1 a with the variation of these conditions. To verify the synergistic effect of H‐bonding and π‐stacking interactions on the chromism of 1 a , the effect of the addition of 2,6‐diacetylaminopyridine ( 3 ), which has strong H‐bonding ability with isoalloxazines, [7c,d] was examined for the emission of 1 a in CHCl 3 . The emission color of a 3.2 mM solution of 1 a in CHCl 3 was changed gradually from orange to yellow upon addition of 0–4.0 equivalents of 3 under UV irradiation at 298 K (Figure 10a).…”

Section: Multistimuli‐responsive Absorption and Emission Properties O...mentioning

confidence: 99%

Multistimuli‐Responsive Chromism of Vinylene‐Linked Bisflavin Based on the Aggregation and Redox Properties

Kawamorita

Okamoto

2022

Chemistry A European J

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Multistimuli‐responsive chromism was observed for vinylene‐linked bisflavin 1 a with an extended π‐conjugated platform. The yellow emission of a dilute solution of 1 a in CHCl3 (0.2 mM) observed at 298 K under UV excitation was changed to orange or red emission upon (1) an increase of concentration, (2) a decrease of temperature, and (3) variation of the solvent. This is in contrast to the almost non stimuli‐responsive chromism of the N‐methylated bisflavin analogue 1 b and monoflavin 2 a. Mechanistic investigation by 1H NMR analysis under various conditions revealed that the extended π‐conjugation platform and imide moiety of 1 a generate controllability in the formation of lower‐ and higher‐ordered aggregates, which induce variation of the emission color upon change. Bisflavin 1 a also exhibited redox‐induced chromism, where the orange emission of 1 a was quenched by the addition of hydrazine under anaerobic conditions, and changed back to the original emission upon subsequent bubbling of O2 gas.

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Section: Multistimuli‐responsive Absorption and Emission Properties O...mentioning

confidence: 99%

Multistimuli‐Responsive Chromism of Vinylene‐Linked Bisflavin Based on the Aggregation and Redox Properties

Kawamorita

Okamoto

2022

Chemistry A European J

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“…25 3,4,5-trialkoxyphenyl groups as terminal functions were applied in the same reaction, with the same efficiency. 26 In these cases, the noncovalent interaction concerns the catalytic site.…”

Section: Non-covalently Formed Dendritic Catalystsmentioning

confidence: 99%

The Role of Noncovalent Interactions in the Efficiency of Dendrimers in Catalysis

Caminade

2019

Noncovalent Interactions in Catalysis

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Dendrimers are nanometric macromolecules constituted of repetitive branched units, radially arranged around a central core. They are synthesized step-by-step, generally using a divergent process from this core. Dendrimers have many properties, and among them, catalysis is a major field. Two main domains are studied, on one side the search for the positive "dendrimer effect", i.e. an increase of the catalytic efficiency when the size of the dendrimer increases, and on the other side the encapsulation of catalytically active nanoparticles inside dendrimers. In both cases, non-covalent interactions are involved. This chapter displays the important role played by non-covalent interactions on the properties of dendrimers in catalysis. A first part will concern the dendrimer effect, then a short part will display non-covalently formed catalytic dendrimers, and the last part will concern dendrimers encapsulating catalytic nanoparticles.

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“…61 The Naota group have designed dendritic organocatalysts featuring association complexes in dendritic cores consisting of synthetic flavin with diaminopyridine and melamine receptors for aerobic hydrogenation of styrene at ambient conditions. 62 The Kaneda group reported catalysis in the internal nanocavity of polypropylenimine (PPI) dendrimers functionalized with C 16 alkyl chains acting as efficient tertiary amine catalysts for the intramolecular Michael reaction. The substrate was accommodated in a reactive conformation within a sterically confined nanocavity consisting of regularly arranged tertiary amino groups of the PPI dendrimers.…”

Section: Syn Thesismentioning

confidence: 99%

Catalysis Inside Dendrimers

et al. 2015

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Modern methods that involve intradendritic catalysis are introduced in this feature article. Supramolecular principles, therefore, derive from the concept of the unimolecular dendritic micelle introduced by Newkome. When the micellar effect is combined with intradendritic ligand acceleration, copper(I) catalysts or palladium nanoparticles (PdNPs) are required at the ppm level for efficient reactions. Applications range from organic catalysis to catalysis by metal complexes of intradendritic ligands and dendrimer-stabilized nanoparticles (NPs) that are located at the dendrimer core or between the dendrimer tethers. Bimetallic nanoparticle-cored dendrimers including superparamagnetic iron oxide nanoparticles (SPIONs) are especially promising due to very facile magnetic separation.

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Non-covalently dendronized flavins as organocatalysts for aerobic reduction of olefins

Cited by 15 publications

References 39 publications

Multistimuli‐Responsive Chromism of Vinylene‐Linked Bisflavin Based on the Aggregation and Redox Properties

Multistimuli‐Responsive Chromism of Vinylene‐Linked Bisflavin Based on the Aggregation and Redox Properties

The Role of Noncovalent Interactions in the Efficiency of Dendrimers in Catalysis

Catalysis Inside Dendrimers

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