Dendrimers as Support for Recoverable Catalysts and Reagents

Heerbeek, Rieko van; Kamer, Paul C. J.; Leeuwen, Piet W. N. M. van; Reek, Joost N. H.

doi:10.1021/cr0103874

Cited by 607 publications

(270 citation statements)

References 127 publications

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“…9 An important conclusion of this study was that the zwitterionic Pd(II) complex can stabilize itself intermolecularly without counterions. In case of metallodendritic assembly [1] …”

Section: Resultsmentioning

confidence: 99%

“…10 Synthesis of the Metallodendritic Assemblies. The first-, second-, and third-generation dendritic entities [1] Figure 3), yielding a series of six different metallodendritic assemblies ( Figure 5). In addition, dendritic entity [4] 8+ ( Figure 2), which bears an apolar outer shell of dodecyl groups, was used as a support for [6] -.…”

Section: A R T I C L E Smentioning

confidence: 99%

“…In addition, dendritic entity [4] 8+ ( Figure 2), which bears an apolar outer shell of dodecyl groups, was used as a support for [6] -. The noncovalent attachment of the Pd(II) complexes to the octacationic entities was performed according to the synthetic procedure outlined for [1][5] 8 . The dendrimers and Pd complexes were mixed in dichloromethane, followed by aqueous washings and passive dialysis 16 in order to remove formed [NBu 4 ]Br and to remove excess of the unsupported [NBu 4 ] salts of the Pd complexes, which were found to permeate through the dialysis membrane unlike the ionic core-shell dendrimers and their corresponding assemblies.…”

Section: A R T I C L E Smentioning

confidence: 99%

“…In the 1 H NMR spectra of the metallodendritic assemblies diagnostic shifts were observed compared to the spectra of the octaionic dendrimers [1] Figure S1, parts b and c in the Supporting Information). Shifts to lower frequencies (0.2-0.5 ppm) were found for protons nearby the ammonium sites in the core of the dendritic supports, i.e., NMe 2 and benzylic protons of the ammonium groups, and aryl groups of the inner part of the dendritic shell.…”

Section: A R T I C L E Smentioning

confidence: 99%

“…The protons of Pd(II) complex [5] -showed shifts to lower frequencies in the presence of the dendritic supports. For [1][5] 8 , the most pronounced shift was found for the protons of the CH 2 -Si group of the C 6 SiMe 2 tether unit of [5] -(0.13 ppm). Upon increasing the dendrimer generation the shifts to lower frequencies of the protons of the tether unit increase.…”

Section: A R T I C L E Smentioning

confidence: 99%

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Ionic Core−Shell Dendrimers with an Octacationic Core as Noncovalent Supports for Homogeneous Catalysts

et al. 2006

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Ionic core-shell dendrimers with an octacationic core have been applied as noncovalent supports for homogeneous catalysts. Catalytically active arylpalladium complexes, which bear a tethered sulfato group, were noncovalently attached to the ionic core-shell dendritic supports via a straightforward ionexchange reaction under mild conditions. Diagnostic shifts in 1 H NMR and Overhauser contacts show that the sulfato groups of the catalysts are located close to the octacationic core of the dendritic support in the resulting assemblies. The location of the catalytic Pd(II) sites has been varied via two strategies: by increasing the dendrimer generation and/or by shortening of the sulfato tether. In addition, a metallodendritic assembly was prepared, which bears an alternative shell of apolar dodecyl groups. Both the dendrimer size and the nature of the dendritic shell have no influence on the binding properties of the dendritic supports, i.e., the octacationic dendrimers of generations 1-3 form discrete 1:8 assemblies with the arylpalladium complexes. The structural aspects and the nature of the metallodendritic assemblies have been studied by means of pulse gradient spin-echo NMR diffusion methods, Overhauser spectroscopy, and electron microscopy (TEM). These techniques showed that the dendritic supports and arylpalladium complexes are strongly associated in solution to give unimolecular assemblies of nanoscopic dimensions. Membrane dialysis can recover these metallodendritic assemblies due to their nanoscopic size. The catalytic performances of the metallodendritic assemblies are comparable, but slightly lower than the performance of the unsupported catalyst.

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“…9 An important conclusion of this study was that the zwitterionic Pd(II) complex can stabilize itself intermolecularly without counterions. In case of metallodendritic assembly [1] …”

Section: Resultsmentioning

confidence: 99%

Section: A R T I C L E Smentioning

confidence: 99%

Section: A R T I C L E Smentioning

confidence: 99%

Section: A R T I C L E Smentioning

confidence: 99%

Section: A R T I C L E Smentioning

confidence: 99%

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Ionic Core−Shell Dendrimers with an Octacationic Core as Noncovalent Supports for Homogeneous Catalysts

et al. 2006

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Iron: Organometallic ChemistryBased in part on the article Iron: Organometallic Chemistry by James R. Green which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.

Paley¹

2005

Encyclopedia of Inorganic Chemistry

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Studies involving the preparation, reactivity, and properties of the organometallic complexes of iron (compounds possessing a FeC bond) have played a central role in the growth of organometallics as a major subdiscipline with chemistry. From the discovery of ferrocene in the 1950s to the present day, interest and research activity remain high. This entry provides a survey of this large and diverse area of organometallic chemistry, and is arranged by increasing hapticity of the organic ligand of interest that is bound to iron. Included are discussions of the chemistry of iron σ‐alkyl, acyl, alkynyl, and vinyl complexes, iron carbenes, η1‐ and η3‐allyl iron complexes, η2‐alkene and η4‐diene iron complexes, trimethylenemethane and cyclobutadiene complexes of iron, cationic iron pentadienyl, cyclohexadienyl, and arene complexes, and ferrocenes and heteroferrocenes.

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Dendrimers

Svenson¹

2006

Kirk-Othmer Encyclopedia of Chemical Technology

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Dendritic polymers (dendrimers) are synthesized in a layer‐by‐layer fashion around a core molecule. Depending on the number of chemical functionalities and the shape of the core, dendrimers of various shapes and complexities can be produced with very low polydispersity. The high level of control over the architecture of dendrimers, their size, shape, branching length and density, and their surface functionality, makes these compounds ideal materials in medical and technical applications, such as drug delivery, gene transfection, imaging, luminescence, quantum dot stabilization, catalysis and waste remediation. The active agents may either be encapsulated into the interior of the dendrimers or they can be chemically attached or physically adsorbed onto the dendrimer surface, with the option to tailor the properties of the dendritic carrier to the specific needs of the active material in its specific applications. Surface modified dendrimers themselves may act as nanodrugs against tumors, bacteria, and viruses. Recent successes in simplifying the synthesis of dendrimers, such as the “lego” and “click” approaches, have provided a vastly expanded variety of dendritic compounds, while at the same time reducing the cost of their production.

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Dendrimers as Support for Recoverable Catalysts and Reagents

Cited by 607 publications

References 127 publications

Ionic Core−Shell Dendrimers with an Octacationic Core as Noncovalent Supports for Homogeneous Catalysts

Ionic Core−Shell Dendrimers with an Octacationic Core as Noncovalent Supports for Homogeneous Catalysts

Iron: Organometallic ChemistryBased in part on the article Iron: Organometallic Chemistry by James R. Green which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.

Dendrimers

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