Dendrimer–Dye Assemblies as Templates for the Formation of Gold Nanostructures

Düring, Jasmin; Alex, Wiebke; Zika, Alexander; Branscheid, Robert; Spiecker, Erdmann; Gröhn, Franziska

doi:10.1021/acs.macromol.7b00752

Cited by 10 publications

(12 citation statements)

References 51 publications

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“…[15][16][17][18][19][20][21][22][23][24][25][26][75][76][77][78][79][80] The most common used dendrimers are the commercially available poly(amidoamine) (PAMAM) type dendrimers. 17,[81][82][83] Esumi et al 19 have synthesized Pt, Pd and Ag nanoparticles using PAMAM dendrimers as stabilizer. The influence of various generations of dendrimers on the catalytic activity of the metal nanoparticles has been investigated.…”

Section: Carriers and Nanoreactors: A Surveymentioning

confidence: 99%

Catalysis by Metallic Nanoparticles in Solution: Thermosensitive Microgels as Nanoreactors

Roa

Angioletti‐Uberti

Lü

et al. 2018

Zeitschrift Für Physikalische Chemie

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Metallic nanoparticles have been used as catalysts for various reactions, and the huge literature on the subject is hard to overlook. In many applications, the nanoparticles must be affixed to a colloidal carrier for easy handling during catalysis. These "passive carriers" (e.g., dendrimers) serve for a controlled synthesis of the nanoparticles and prevent coagulation during catalysis.Recently, hybrids from nanoparticles and polymers have been developed that allow us to change the catalytic activity of the nanoparticles by external triggers. In particular, single nanoparticles embedded in a thermosensitive network made from poly(N-isopropylacrylamide) (PNIPAM) have become the most-studied examples of such hybrids: Immersed in cold water, the PNIPAM network is hydrophilic and fully swollen. In this state, hydrophilic substrates can diffuse easily through the network, and react at the surface of the nanoparticles. Above the volume transition located at 32°C, the network becomes hydrophobic and shrinks. Now hydrophobic substrates will preferably diffuse through the network and react with other substrates in the reaction catalyzed by the enclosed nanoparticle. Such "active carriers", may thus be viewed as true nanoreactors that open new ways for the use of nanoparticles in catalysis. 3In this review, we give a survey on recent work done on these hybrids and their application in catalysis. The aim of this review is threefold: We first review hybrid systems composed of nanoparticles and thermosensitive networks and compare these "active carriers" to other colloidal and polymeric carriers (e.g., dendrimers). In a second step we discuss the model reactions used to obtain precise kinetic data on the catalytic activity of nanoparticles in various carriers and environments. These kinetic data allow us to present a fully quantitative comparison of different nanoreactors. In a final section we shall present the salient points of recent efforts in the theoretical modeling of these nanoreactors. By accounting for the presence of a free-energy landscape for the reactants' diffusive approach towards the catalytic nanoparticle, arising from solvent-reactant and polymeric shell-reactant interactions, these models are capable of explaining the emergence of all the important features observed so far in studies of nanoreactors. The present survey also suggests that such models may be used for the design of future carrier systems adapted to a given reaction and solvent. 4

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Section: Carriers and Nanoreactors: A Surveymentioning

confidence: 99%

Catalysis by Metallic Nanoparticles in Solution: Thermosensitive Microgels as Nanoreactors

Roa

Angioletti‐Uberti

Lü

et al. 2018

Zeitschrift Für Physikalische Chemie

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“…A useful property of dendrimers is their ability to encapsulate functional cargo; we therefore finally investigate how we can exploit this property to make hierarchical supramolecular structures. − In particular, we have prepared Au nanoparticles (∼2 nm) inside PAMAM dendrimers by reducing gold salt in the presence of PAMAM. In this case, we selected G7 PAMAM, because lower generation dendrimers with a less well-defined cavity cannot successfully encapsulate Au nanoparticles.…”

Section: Resultsmentioning

confidence: 99%

Hierarchical Assemblies of Dendrimers Embedded in Networks of Lanthanide-Based Supramolecular Polyelectrolytes

et al. 2019

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Supramolecular assemblies of dendrimers, with defined structures and tunable functionalities, are promising functional materials. Here we report a ternary system (lanthanide ion/bis-ligand/PAMAM dendrimer) capable of assembling in a cooperative way by forming a complex between anionic (metal–ligand) coordination polymers and the cationic PAMAM dendrimers. In off-stoichiometric mixtures, charge-stabilized spherical nanoparticles of ∼100 nm appear; they have either negative or positive surface charges depending on what the excess component is. Introducing different trivalent lanthanide ions, Ln(III), in the coordination allows tuning both the luminescence emission spectrum and the magnetic relaxivity without affecting the assembly process or the final structure of the particles; this makes them interesting in the context of application. Moreover, the incorporated dendrimer allows us to add functional nanocargo, for example, Au nanoparticles in the cavities of these molecules, again without disturbing the assembly. In this novel way, we obtain versatile, multilevel hierarchical supramolecular dendrimer-containing assemblies with good control over their structures and functionalities. This is very difficult to achieve with conventional covalent compounds but becomes possible because of the supramolecular nature of the coordination polymers and the strong cooperative assembly.

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“…An interplay involving Hamaker attraction, coordination, steric and dipole effects in addition to electrostatics was discussed to understand the structure formation ( Düring and Gröhn, 2016 ). Finally, an even larger structural variety becomes available when first building an organic supramolecular structure by electrostatic self-assembly and secondly use remaining charges for an electrostatic nanotemplating within this suprastructure ( Düring et al, 2015 ; Düring et al, 2017a ). When using a light-responsive dye, it is also possible to switch the size and compactness of organic-inorganic hybrid structure such as the CdS–dendrimer fibers via light irradiation ( Düring and Gröhn, 2016 ).…”

Section: Electrostatic Nanotemplating To Create Organic-inorganic Hyb...mentioning

confidence: 99%

Functional Nano-Objects by Electrostatic Self-Assembly: Structure, Switching, and Photocatalysis

2022

Self Cite

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The design of functional nano-objects by electrostatic self-assembly in solution signifies an emerging field with great potential. More specifically, the targeted combination of electrostatic interaction with other effects and interactions, such as the positioning of charges on stiff building blocks, the use of additional amphiphilic, π−π stacking building blocks, or polyelectrolytes with certain architectures, have recently promulgated electrostatic self-assembly to a principle for versatile defined structure formation. A large variety of architectures from spheres over rods and hollow spheres to networks in the size range of a few tenths to a few hundred nanometers can be formed. This review discusses the state-of-the-art of different approaches of nano-object formation by electrostatic self-assembly against the backdrop of corresponding solid materials and assemblies formed by other non-covalent interactions. In this regard, particularly promising is the facile formation of triggerable structures, i.e. size and shape switching through light, as well as the use of electrostatically assembled nano-objects for improved photocatalysis and the possible solar energy conversion in the future. Lately, this new field is eliciting an increasing amount of understanding; insights and limitations thereof are addressed in this article. Special emphasis is placed on the interconnection of molecular building block structures and the resulting nanoscale architecture via the key of thermodynamics.

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Dendrimer–Dye Assemblies as Templates for the Formation of Gold Nanostructures

Cited by 10 publications

References 51 publications

Catalysis by Metallic Nanoparticles in Solution: Thermosensitive Microgels as Nanoreactors

Catalysis by Metallic Nanoparticles in Solution: Thermosensitive Microgels as Nanoreactors

Hierarchical Assemblies of Dendrimers Embedded in Networks of Lanthanide-Based Supramolecular Polyelectrolytes

Functional Nano-Objects by Electrostatic Self-Assembly: Structure, Switching, and Photocatalysis

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