A 4.6 nm-sized coordination sphere confines 24 pendant coronene molecules at its core. The confined coronene molecules are fluid, forming a liquid "coronene nanodroplet" that could never exist in bulk. C(60) dissolves in this nano solvent with a high local concentration.
Ein sphärischer Pd12L24‐Komplex dient als Templat bei der Synthese von hohlen Siliciumdioxidnanopartikeln, die Metallcluster mit definierter Atomzahl n in ihrem Inneren enthalten. Der eingeschlossene Pd12L24‐Komplex wird in der schützenden Siliciumdioxidhülle zunächst in einen (PdO)n ‐Oxidcluster umgewandelt und anschließend zum Pdn‐Metallcluster reduziert.
Nanoparticles with core-shell structures can exhibit unique material properties and promise a variety of applications in materials science, optics, catalysis, and biophysics. [1][2][3][4][5][6][7][8][9][10][11] The precise synthesis of core-shell nanoparticles is of utmost importance as the material properties depend on the constituent elements as well as the size and shape of the nanoparticles. The synthesis of core-shell nanoparticles is typically carried out by coating the surface of the core nanoparticles with metal ions or metal alkoxides in solution, where the controlled growth of the core nanoparticles and the outer shells is achieved by modulating the synthetic conditions (e.g., temperature, concentration, solvent, and pH value). However, the preparation of both the highly monodisperse core nanoparticles and the subsequent coreshell nanoparticles remains difficult. Recently, several groups have utilized hollow assemblies and media, such as reverse micelles, to control the growth of core-shell nanoparticles, in which the hollow interior acts as a template. [12][13][14] Unfortunately, the templating assemblies are themselves not monodisperse and thus the precise control of nanoparticle growth remained elusive. Furthermore, the large size of the template assemblies precludes the synthesis of small (< 10 nm) coreshell nanoparticles.Recently we published the synthesis of monodisperse SiO 2 nanoparticles using structurally exact coordination spheres as templates.[15] The M 12 L 24 spheres self-assembled from 12 Pd 2+ ions (M) and 24 bent bridging ligands (L) [15][16][17][18][19][20][21] and presented a sugar-coated interior that templated the precise synthesis of highly monodisperse SiO 2 nanoparticles with diameters of 2-4 nm using the sol-gel condensation of alkoxysilanes. Herein, we describe the elaboration of monodisperse SiO 2 nanoparticles confined within the template sphere with a metal oxide (MO 2 ; where M = Ti or Zr) layer to generate monodisperse core-shell nanoparticles (Figure 1). The core-shell nanoparticles (SiO 2 /TiO 2 , SiO 2 /ZrO 2 ) have diameters of 3 nm and preserve the highly monodisperse molecular weight distributions (M w /M n < 1.01) as characterized by TEM and MS analyses.Self-assembled nanosphere 1 (nitrate salt unless otherwise noted) with the templating glucose interior lining was prepared from sugar-appended ligand 2 and Pd(NO 3 ) 2 in DMSO. With sphere 1 as a template, silica (SiO 2 ) core nanoparticles were prepared as follows: tetramethoxysilane (TMOS, 100 equiv) was added to sphere 1 (80 mm, CDCl 3 / [D 6 ]DMSO 9:1) and the mixture was stirred at room temperature for four days. Upon hydrolysis and condensation of TMOS inside 1, NMR signals of the sphere framework significantly broadened because of the growth of SiO 2 nanoparticles within the inner cavity (Figure 2 a,b). Under laser desorption ionization mass spectrometry (LDI-MS) conditions, the shell framework of 1 was destroyed and we could directly confirm the formation of highly monodisperse silica nanoparticles with molec...
Ein sphärischer Pd12L24‐Komplex dient als Templat bei der Synthese von hohlen Siliciumdioxidnanopartikeln, die Metallcluster mit definierter Atomzahl n in ihrem Inneren enthalten. Der eingeschlossene Pd12L24‐Komplex wird in der schützenden Siliciumdioxidhülle zunächst in einen (PdO)n‐Oxidcluster umgewandelt und anschließend zum Pdn‐Metallcluster reduziert.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.