Magnetically Recoverable Catalysts with Dendritic Ligands for Enhanced Catalysis and Easy Separation

Bronstein, Lyudmila M.

doi:10.1002/cctc.201500007

Cited by 16 publications

(9 citation statements)

References 8 publications

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“…10,11,[122][123][124][125][126][127] Some of these nanostructures have involved dendritic or dendronic stabilization in order to improve catalyst loading and recovery by steric protection. [128][129][130][131] Therefore two strategies may be used. The first involves covalent binding of dendrons containing triazole or related ligands to a silica-coated iron oxide core (Figure 2), 128 whereas the second consists of impregnating dendritically preformed nanoparticles on a magnetic support such as maghemite γ-Fe 2 O 3 @SiO 2 nanoparticles (Figure 3) by sonification.…”

Section: Catalysis By Nanoparticle-cored Dendrimersmentioning

confidence: 99%

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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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Section: Catalysis By Nanoparticle-cored Dendrimersmentioning

confidence: 99%

“…129 In parallel, the Bronstein group also designed magnetically recoverable catalysts based on polyphenylenepyridyl dendrons and dendrimers. 129,130…”

Section: Catalysis By Nanoparticle-cored Dendrimersmentioning

confidence: 99%

Catalysis Inside Dendrimers

et al. 2015

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“…As a particular type of magnetic nanoparticles, superparamagnetic iron oxide nanoparticles (SPIONs) are more widely available than other MNPs due to advantages such as biologically well-accepted constituents, established size-selective preparation, diminished agglomeration, ease of preparation, and lower cost 26 , 45 , 47 – 57 . On the other hand, heterogenization of the active sites of usual dendritic catalysis has been pursued by either attaching the catalyst covalently within the dendrimer core or at the branch termini as well as through supramolecular interactions such as metal–ligand, hydrogen bonding, aromatic π–π stacking, hydrophobic and van der Waals forces 22 , 26 , 51 , 58 – 61 . Therefore, design and preparation of new magnetic dendritic catalytic systems by appropriate application of dendron segments which can be expanded to 2D or 3D covalent organic frameworks (COFs) is still in high demand.…”

Section: Introductionmentioning

confidence: 99%

Dendrons containing boric acid and 1,3,5-tris(2-hydroxyethyl)isocyanurate covalently attached to silica-coated magnetite for the expeditious synthesis of Hantzsch esters

Sam

Dekamin

Alirezvani

2021

Sci Rep

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A new multifunctional dendritic nanocatalyst containing boric acid and 1,3,5-tris(2-hydroxyethyl)isocyanurate covalently attached to core–shell silica-coated magnetite (Fe3O4@SiO2@PTS-THEIC-(CH2)3OB(OH)2) was designed and properly characterized by different spectroscopic or microscopic methods as well as analytical techniques used for mesoporous materials. It was found that the combination of both aromatic π–π stacking and boron–oxygen ligand interactions affords supramolecular arrays of dendrons. Furthermore, the use of boric acid makes this dendritic catalyst a good choice, from corrosion, recyclability and cost points of view. The catalytic activity of Fe3O4@SiO2@PTS-THEIC-(CH2)3OB(OH)2, as an efficient magnetically recoverable catalyst, was investigated for the synthesis of polyhydroacridines (PHAs) as well as polyhydroquinolines (PHQs) via one-pot multicomponent reactions of dimedone and/or ethyl acetoacetate, different aldehydes and ammonium acetate in EtOH under reflux conditions. Very low loading of the catalyst, high to quantitative yields of the desired PHAs or PHQs products, short reaction times, wide scope of the substrates, eliminating any toxic heavy metals or corrosive reagents for the modification of the catalyst, and simple work-up procedure are remarkable advantages of this green protocol. An additional advantage of this magnetic nanoparticles catalyst is its ability to be separated and recycled easily from the reaction mixture with minimal efforts in six subsequent runs without significant loss of its catalytic activity. This magnetic and dendritic catalyst can be extended to new two- and three-dimensional covalent organic frameworks with different applications.

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“…After a deeper examination of its origin, Tomalia published a study relating structure parameters to prediction of dendrimer properties [ 6 , 7 ]. Then, advantageously, the concept of formation of microenvironment with locally modified characteristics was employed in drug delivery [ 8 , 9 ], catalysis [ 10 , 11 , 12 ] or material [ 13 , 14 ] and supramolecular chemistry [ 15 , 16 ]. Although all these applications are based on an interaction of the dendritic molecule with a guest, the studies concerning dendritic effects in anion recognition are rather rare.…”

Section: Introductionmentioning

confidence: 99%

Controlled Anchoring of (Phenylureido)sulfonamide-Based Receptor Moieties: An Impact of Binding Site Multiplication on Complexation Properties

et al. 2021

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The repetition of urea-based binding units within the receptor structure does not only lead to monomer properties multiplication. As confirmed by spectroscopic studies, UV-Vis and 1H-NMR in classical or competitive titration mode, the attachment to a carrier allocates the active moieties to mutual positions predetermining the function of the whole receptor molecule. Bivalent receptors form self-aggregates. Dendritic receptors with low dihydrogen phosphate loadings offer a cooperative complexation mode associated with a positive dendritic effect. In higher dihydrogen phosphate concentrations, the dendritic branches act independently and the binding mode changes to 1:1 anion: complexation site. Despite the anchoring, the dendritic receptors retain the superior efficiency and selectivity of a monomer, paving the way to recyclable receptors, desirable for economic and ecological reasons.

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Magnetically Recoverable Catalysts with Dendritic Ligands for Enhanced Catalysis and Easy Separation

Cited by 16 publications

References 8 publications

Catalysis Inside Dendrimers

Catalysis Inside Dendrimers

Dendrons containing boric acid and 1,3,5-tris(2-hydroxyethyl)isocyanurate covalently attached to silica-coated magnetite for the expeditious synthesis of Hantzsch esters

Controlled Anchoring of (Phenylureido)sulfonamide-Based Receptor Moieties: An Impact of Binding Site Multiplication on Complexation Properties

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