Synthesis and Characterization of Sn/R, Sn/Si−R, and Sn/SiO2 Core/Shell Nanoparticles

Nanometer-sized tin, Sn/R, and Sn/Si−R (R = n -C 4 H 9 ), core/shell nanoparticles have been prepared by the reaction of SnCl 4 or SiCl 4 with Mg 2 Sn in ethylene glycol dimethyl ether (glyme) and subsequently with n -C 4 H 9 Li. Sn/SiO 2 core/shell nanoparticles are produced from the reaction of Mg 2 Sn with SiCl 4 and subsequent reaction with H 2 O 2 . Fourier transform Infrared (FTIR) spectra are consistent with n -butyl surface termination for the n -butyl-capped tin (Sn/ n -butyl) and the silicon- n -butyl capped tin (Sn/Si- n -butyl) core/shell nanoparticles. High-resolution transmission electron microscope (HRTEM) confirms that the core part of Sn/ n -butyl and Sn/Si- n -butyl nanoparticles is consistent with the tetragonal structure of tin, exhibiting lattice fringes of the {200} crystal plane (2.92 Å). The FTIR spectrum of Sn/SiO 2 confirms the evidence of silica capping and selected area electron diffraction (SAED) is consistent with an amorphous shell (SiO 2 ) and crystalline Sn core. Solid-state nuclear magnetic resonance (NMR) spectra and X-ray powder diffraction (XRD) pattern provide supporting evidence for the tetragonal structure of β-tin as the core part of Sn/SiO 2 nanoparticles. The typical size distribution of Sn/ n -butyl, Sn/Si- n -butyl, and Sn/SiO 2 nanoparticles (diameter) range from 7 to 15 nm derived from TEM micrographs. The average radius ratio (Rr) value, (radius of SiO 2 /radius of Sn) for Sn/SiO 2 derived from 24 individual nanoparticles in TEM images is 0.17 (0.02).