Reduction of Au(III) by a β-cyclodextrin polymer in acid medium. A stated unattainable reaction

Martin‐Trasanco, Rudy; Cao, Roberto; Ponce, Hilda Esperanza Esparza; Montero-Cabrera, M. E.; Arratia‐Pérez, Ramiro

doi:10.1016/j.carbpol.2017.08.013

Cited by 19 publications

(18 citation statements)

References 37 publications

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“…CDs are macrocyclic oligosaccharides possessing hydrophobic cavities and hydrophilic group, 17 and this allows them to be used in various applications. β-CD and its derivatives have been extensively used as catalysts in aqueous reactions as diverse as reduction, 18 hydrolysis, 19 oxidation, 20 and coupling reaction 21 because of their ability to solubilize hydrophobic compounds and their ability to recognize different molecules. 22 However, β-CD is poorly soluble in cold water; thus, chemical modifications 23 of β-CD are necessary to improve their selectivity and solubility.…”

Section: Introductionmentioning

confidence: 99%

Highly Efficient Method for Suzuki Reactions in Aqueous Media

et al. 2018

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Herein, we report the crystal structure and characterization of mono-6-( l -aminopropanol)-deoxy-β-cyclodextrin (L n @β-CD). A highly efficient, in situ generated catalyst, PdCl 2 (L n @β-CD), was synthesized for palladium-catalyzed cross-coupling reactions under mild reaction conditions, and the use of this catalyst in Suzuki cross-couplings was investigated. Low palladium loadings of 0.01 mol % PdCl 2 (L n @β-CD) (Pd accounted for approximately 8.4% of the catalyst by mass) were found to be highly efficient for Suzuki cross-couplings in water and afforded the corresponding biaryl compounds in excellent yields. The catalyst can be recycled and reused.

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Section: Introductionmentioning

confidence: 99%

Highly Efficient Method for Suzuki Reactions in Aqueous Media

et al. 2018

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“…In our case, duet oi ts neutral nature, the modified dextran 1 is not expected to have any specific electrostatic influence on the relative compartmentalization of the two ions. However, we believe that temporal isolationb etween the two metal precursors can be achieved due to complexation of Au 3 + by the hydroxyl groups of the dextran.I nteractions of HAuCl 4 with hydroxyl groupso fc arbohydrate units is not uncommon [27] and, in our case, is supported by the negligible formation of turbidity due to the insoluble AgCl, which is insteadt ypicallyo bserved when the same amounts of HAuCl 4 and AgNO 3 are mixed in the absence of dextran.…”

Section: Resultsmentioning

confidence: 99%

One‐Step Photochemical Green Synthesis of Water‐Dispersible Ag, Au, and Au@Ag Core–Shell Nanoparticles

Perez-Lloret

Fraix

Petralia

et al. 2019

Chemistry A European J

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A simple and green synthetic protocol for the rapid and effective preparation of Ag, Au and Au@Ag core–shell nanoparticles (NPs) is reported based on the light irradiation of a biocompatible, water‐soluble dextran functionalized with benzophenone (BP) in the presence of AgNO3, HAuCl4, or both. Photoactivation of the BP moiety produces the highly reducing ketyl radicals through fast (<50 ns) intramolecular H‐abstraction from the dextran scaffold, which, in turn, ensures excellent dispersibility of the obtained metal NPs in water. The antibacterial activity of the AgNPs and the photothermal action of the Au@Ag core–shell are also shown.

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“…No attempt to purify them was made [14,15]. In contrast to this, the β-cyclodextrin-epichlorohydrin polymer can reduce tetrachloroauric acid at a pH of about 3 [16].…”

Section: Introductionmentioning

confidence: 99%

Formation of Aggregate-Free Gold Nanoparticles in the Cyclodextrin-Tetrachloroaurate System Follows Finke–Watzky Kinetics

Pestovsky

Srichana

2022

Nanomaterials

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Cyclodextrin-capped gold nanoparticles are promising drug-delivery vehicles, but the technique of their preparation without trace amounts of aggregates is still lacking, and the size-manipulation possibility is very limited. In the present study, gold nanoparticles were synthesized by means of 0.1% (w/w) tetrachloroauric acid reduction with cyclodextrins at room temperature, at cyclodextrin concentrations of 0.001 M, 0.002 M and 0.004 M, and pH values of 11, 11.5 and 12. The synthesized nanoparticles were characterized by dynamic light scattering in both back-scattering and forward-scattering modes, spectrophotometry, X-ray photoelectron spectroscopy, transmission electron microscopy and Fourier-transform infrared spectroscopy. These techniques revealed 14.9% Au1+ on their surfaces. The Finke–Watzky kinetics of the reaction was demonstrated, but the actual growth mechanism turned out to be multistage. The synthesis kinetics and the resulting particle-size distribution were pH-dependent. The reaction and centrifugation conditions for the recovery of aggregate-free nanoparticles with different size distributions were determined. The absorbances of the best preparations were 7.6 for α-cyclodextrin, 8.9 for β-cyclodextrin and 7.5 for γ-cyclodextrin. Particle-size distribution by intensity was indicative of the complete absence of aggregates. The resulting preparations were ready to use without the need for concentration, filtration, or further purification. The synthesis meets the requirements of green chemistry.

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Reduction of Au(III) by a β-cyclodextrin polymer in acid medium. A stated unattainable reaction

Cited by 19 publications

References 37 publications

Highly Efficient Method for Suzuki Reactions in Aqueous Media

Highly Efficient Method for Suzuki Reactions in Aqueous Media

One‐Step Photochemical Green Synthesis of Water‐Dispersible Ag, Au, and Au@Ag Core–Shell Nanoparticles

Formation of Aggregate-Free Gold Nanoparticles in the Cyclodextrin-Tetrachloroaurate System Follows Finke–Watzky Kinetics

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