Dendrimer-encapsulated nanoparticles: New synthetic and characterization methods and catalytic applications

Abstract

In this article we describe the synthesis, characterization, and applications of dendrimer-encapsulated nanoparticles (DENs). These materials are synthesized using a template approach in which metal ions are extracted into the interior of dendrimers and then subsequently reduced chemically to yield nearly size-monodisperse particles having diameters in the 1-2 nm range. Monometallic, bimetallic (alloy and core@shell), and semiconductor nanoparticles have been prepared by this route. The dendrimer component of these composites serves not only as a template for preparing the nanoparticle replica, but also as a stabilizer for the nanoparticle. In this perspective, we report on progress in the synthesis, characterization, and applications of these materials since our last review in 2005. Significant advances in the synthesis of core@shell DENs, characterization, and applications to homogeneous and heterogeneous catalysis (including electrocatalysis) are emphasized.

Metallodendrimers in three oxidation states with electronically interacting metals and stabilization of size-selected gold nanoparticles

“…The characterizations of the complex 3 are gathered in Supplementary Figs 13-18. The dodecairon complex 4 was synthesized from the reaction between dendron 1 and hexakis(4-iodophenyl)-benzene catalysed by [Pd(PPh 3 ) 2 Cl 2 ] and CuI (Fig. 2a).…”

“…Indeed, the AuNP core size approximately corresponds to the number of Au atoms generated from the triazolyl-coordinated Au III precursors in a single dendrimer. It does for dendron 1, however, because AuNP stabilization by borohydride then predominates in equation (2) in the absence of strong dendritic stabilization.…”

“…T o date, dendrimers and metal nanoparticles (NPs) have been largely involved in materials science including nanomedicine, photonics and supramolecular chemistry [1][2][3][4][5] , and in particular metallodendrimers and dendrimercontaining NPs 2-4,6-11 have been efficiently designed for catalysis [2][3][4] , photophysics [7][8][9][10][11] and sensing [9][10][11][12][13] . Redox-stable metallodendrimers are a specific class of materials allowing redox anion recognition, sensing [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] and biosensing 14,15 that have been used essentially with ferrocene derivatives [12][13][14][15] .…”

“…Redox-stable metallodendrimers are a specific class of materials allowing redox anion recognition, sensing [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] and biosensing 14,15 that have been used essentially with ferrocene derivatives [12][13][14][15] . Although biferrocene-and silicon-bridged biferrocene-terminated dendrimers are known 5,[14][15][16] , no dendrimers have yet been isolated in several oxidation states owing to instability of the oddelectron species.…”

Bipolar Electrodes for Rapid Screening of Electrocatalysts

“…To demonstrate proof of concept, three different cathode materials were tested for their ORR activities. Pt and Au dendrimer-encapsulated nanoparticles (DENs) 25 were dropcast onto the cathodic poles of the top and bottom BPEs, respectively. These materials are denoted as G6-OH(Pt 225 ) and G6-OH(Au 225 ), respectively, to indicate that the individual catalytic nanoparticles consisted of ∼225 atoms and were encapsulated within sixth-generation poly(amidoamine) (PAMAM) dendrimers terminated with hydroxyl functional groups.…”