Synthesis and Characterization of NiSn Dendrimer-Encapsulated Nanoparticles

Abstract

We report the synthesis and characterization of NiSn dendrimer-encapsulated nanoparticles (DENs) with sizes in the range of approximately 1.2 nm. These types of materials have potential applications in energy storage, and particles in the 1-3 nm size range are particularly attractive for this use. The NiSn DENs described here contain an average of 147 atoms and are encapsulated within hydrophobic, sixth-generation poly(amidoamine) dendrimers. DENs prepared using four different Ni/Sn ratios, along with monometallic Ni and Sn DENs, are described. To prevent oxidation, the synthesis was carried out under dry conditions in toluene. These bimetallic DENs were characterized by UV-vis spectroscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The results indicate that the compositions of the nanoparticles reflect the ratio of Ni(2+) and Sn(2+) used in the first step of the synthesis; the NiSn nanoparticles remain encapsulated within the dendrimers, and when dry they have a degree of stability even after a short exposure to air.

Electrochemical Activity of Dendrimer-Stabilized Tin Nanoparticles for Lithium Alloying Reactions

“…35,38 Note that the data shown in Figure 1 are also fully consistent with our previous report of bimetallic NiSn DENs synthesized using G6-C 12 dendrimers in organic solvents. 35 Importantly, control experiments conducted in the absence of the dendrimer resulted in immediate precipitation of a white solid, presumably bulk Sn, upon addition of BH 4 − . This clearly implicates the dendrimer as a stabilizing agent, though the UV−vis data do not provide direct evidence for actual encapsulation of Sn nanoparticles.…”

Clickable poly(ester amine) dendrimer-grafted Fe3O4 nanoparticles prepared via successive Michael addition and alkyne–azide click chemistry

“…The general preparation method for dendrimer protected metal nanoparticles depends on complexation of the metal cations with amine groups in the dendrimer, followed by reduction with a chemical reductant. 15,16 Development of nanoparticles with specific functional properties has attracted considerable attention in recent years due to their promising applications in optics, drug release, biomedicine, catalysis, electrochemistry and as sensing materials. [17][18][19][20][21] A widely used method for designing and fabrication of nanoparticles with tailored surface properties is surface modification by covalently tethered functional polymers.…”

Metal ion remediation by polyamidoamine dendrimers: a comparison of metal ion, oxidation state, and titania immobilization

“…This conclusion was corroborated by an in-depth NMR study that showed innermost methylene groups as most sensitive to Pd ion chelation and concluded that the Pd was encapsulated within the dendrimer (Gomez et al 2008). A variety of metal ions (e.g., Pt (Knecht et al 2008a, b;Zhao and Crooks 1999), Pd (Gomez et al 2008;Knecht et al 2008a, b), Rh , Cu (Balogh and Tomalia 1998;Zhao et al 1998), Ni (Castillo and Kuhn 2012;Gates et al 2010;Knecht et al 2006), Fe (Castillo and Kuhn 2012;Knecht and Crooks 2007), Au (Knecht et al 2008a, b), and Sn (Gates et al 2010) chelated by dendrimers for the purposes of nanoparticle synthesis illustrate the usefulness of applying dendrimers to water purification. Of those studies above that occurred in aqueous solutions, a wide variety of complexation times were required.…”