Chemically Functional Alkanethiol Derivitized Magnetic Nanoparticles
- PDF / 157,087 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 5 Downloads / 187 Views
Q6.4.1
Chemically Functional Alkanethiol Derivitized Magnetic Nanoparticles
David A. Fleming, Michael Napolitano, Mary Elizabeth Williams* The Pennsylvania State University, Department of Chemistry, 152 Davey Laboratory, University Park, PA, 16802, U.S.A. ABSTRACT Chemically functional magnetic nanoparticles, comprised of an Fe core encased in a thin Au shell, have been prepared by sequential high temperature decomposition of organometallic compounds in a coordinating solvent. A novel approach to encapsulate the Fe core in Au has been developed. TEM analysis confirms that the nanoparticles are monodisperse (~20%) with average diameters of 8nm. The nanoparticles were subsequently functionalized with alkanethiolate ligands, which prevent aggregation, enable solubility in a range of solvents (both hydrophobic and hydrophilic), and permit subsequent derivatization (e.g., via ligand exchange reactions). The functionalized particles are characterized using high-resolution transmission electron microscopy (HRTEM), X-ray powder diffraction (XRD) and ultraviolet-visible (UVVis) absorption spectroscopy. We have utilized place-exchange to impart chemical functionality to the nanoparticles by attaching either (1) thiol-derivatized redox moieties (e.g., ferrocene) or (2) alkanethiols with terminal reactive groups such as alcohols, amines and carboxylic acids. This paper presents our preliminary investigations of the voltammetry of the former class of these magnetic core/shell nanoparticles.
INTRODUCTION The preparation and characterization of novel nanometer scale materials has led to an exponential increase in research activity concerned with examination of the fundamental properties and potential applications of these materials. Metal nanoparticles, for example, have been applied to innovative applications ranging from electronics1 and optics2 to DNA sensing3 and catalysis.4 The utility of magnetic nanoparticles has recently been described5 and demonstrated in a few cases for ultrahigh density information data storage,6 contrast agents in medical imaging technologies7, and ‘spintronics’8 (i.e., spin-based data transfer and storage). For example, Co and FePt nanoparticles have been shown to be useful for the preparation of highly ordered three-dimensional magnetic superlattices.9 There have been several demonstrations of the preparation of magnetic particles in the 10 nm – 2 µm diameter range, comprised of either metal-coated polymeric beads or polymer-coated magnetic particles,10 which typically lack chemical functionality (i.e. synthetic reactivity) or whose electronic or magnetic properties have not been systematically examined. A critical need remains for the synthetic control of their size and composition, and extension of these materials to broader applications requires the design and synthesis of chemically functional magnetic nanoparticles. Several strategies have been developed for the synthesis of magnetic nanoparticles, most notably those reported by Murray et al., which rely on the thermal decomposition of small
Data Loading...
