New Horizon of Nanoparticle and Cluster Catalysis with Dendrimers

Abstract

Among various approaches synthesizing metal nanoparticles and tiny clusters, a template method using dendrimers has significant advantages over other chemical approaches with respect to their synthetic precision and the scalability. A dendrimer of polydentate ligands assembles metal ions or salts into the interior allowing production of metal nanoparticles in the dendrimer. The dendrimer-encapsulated nanoparticles (DENs) exhibit unique and remarkable catalytic properties depending on the size and elemental formula. Recent advances in dendrimer chemistry even enabled the atom precise synthesis of subnanometer metal clusters that have been impossible to prepare by wet chemical methods. In addition, not only for the synthesis of metal nanoparticles and clusters, the dendrimer itself can also provide the modulation of activity and selectivity in the catalysis. In this review, we summarized the most relevant research in which the dendrimer was employed as the template, modulator, or stabilizer for nanoparticle synthesis for catalytic applications.

Theoretical Analysis of the Mackay Icosahedral Cluster Pd55(PiPr3)12(μ3‐CO)20: An Open‐Shell 20‐Electron Superatom

“…Finally, note that the present study is also relevant to catalysis as Pd 55 clusters are close to the optimal cluster size for maximum catalytic activity of Pd clusters and small nanoparticle catalysts. [59][60][61]…”

Comparison of Structure and Local Dynamics of Two Peptide Dendrimers with the Same Backbone but with Different Side Groups in Their Spacers

“…The cumulative charge distribution Q(r) is the integral characteristic of the charge distribution q(r). It can be calculated from Equation (10), where the integral has the variable upper limit…”

The Role of Branch Cell Symmetry and Other Critical Nanoscale Design Parameters in the Determination of Dendrimer Encapsulation Properties

“…Subsequent metal reduction within these dendrimer templates produced a variety of precise metal atom nano-clusters, which could be controlled atom by atom. This area has been reviewed by Yamamoto et al, elsewhere [84]; whereas, the general area of dendrimer-based metal encapsulation remains very active and has been reviewed extensively by others [60,86]. It is noteworthy that both the dendrimer core and the branch cell symmetry of certain dendrimers such as an EDA core poly(propyleneimine) (PPI) dendrimer may strongly influence and define specific metal coordination patterns within the dendrimer interior as reported by de la Mata et al [87].…”

“…Typical, nitrogen ligand containing, symmetrical branch cell dendrimers suitable for metal salt and metal cluster encapsulations including: (a) G4-poly(amidoamine) (PAMAM), (b) G3-poly (propylenimine) (PPI) and (c) G-4-poly(phenylazomethine) (DPA) dendrimers. Reprinted with permissions from[84]. Copyright 2019 American Chemical Society.…”