Formation of Monodisperse FePt Alloy Nanocrystals Using Air-Stable Precursors: Fatty Acids as Alloying Mediator and Reductant for Fe³⁺ Precursors

Abstract

High quality FePt nanocrystals were synthesized by a simple and high performance synthetic method in a hydrocarbon solvent. Instead of a toxic and dangerous Fe(CO)(5) precursor, air-stable and generic inorganic and organic iron salts were used as the iron precursors. Fatty acid molecules were identified as both efficient reducing reagents for the Fe(3+) precursors and as an alloying mediator. The alloying process occurred in a two-step fashion. The Pt nanocrystal seeds initially formed at relatively low temperatures, with the need to be stabilized by a small amount of amines. Conversely, the final FePt nanocrystals could be stabilized with fatty acids as the main ligands. The mechanisms revealed here not only help to understand the formation of alloy nanocrystals but also shed new light on the formation of transition metal oxide nanocrystals using metal fatty acid salts as the precursors.

Monodisperse upconversion NaYF4 nanocrystals: Syntheses and bioapplications

“…2, the broad band at 3435 cm -1 is characteristic of the O-H (COO-H) stretching vibration. The bands at 2924 and 2854 cm -1 can be assigned to the asymmetric (ν as ) and symmetric (ν s ) stretching [37,38]. These data confirm the presence of oleic acid on the nanoparticle surface.…”

Influence of carbon chain length on the synthesis and yield of fatty amine-coated iron-platinum nanoparticles

“…Moreover, for applications involving magnetic resonance imaging (MRI) for cancer detection, a high magnetic moment is preferable, as this correlates with a higher contrast enhancement in the magnetic resonance images. Our synthesized TDA-SIPPs show higher degree of monodispersity, as well as higher saturation magnetizations compared to other SIPPs previously reported in the literature [8-10]. Therefore, SIPPs synthesized using TDA could be useful not only due to their ‘greener’ method of synthesis and ease of scaling up the synthesis but also as potentially better MRI contrast agents for cancer detection.…”

“…There is much interest currently in alternative methods of nanoparticle synthesis, which use relatively non-toxic starting precursors and are environmentally friendly. It is now possible to prepare nanoparticles using much less toxic chemical precursors, such as iron fatty acids [2,8-10]. These so-called green synthesis methods are much less toxic and can produce relatively stable and uniform magnetic nanoparticles [8,10].…”

“…It is now possible to prepare nanoparticles using much less toxic chemical precursors, such as iron fatty acids [2,8-10]. These so-called green synthesis methods are much less toxic and can produce relatively stable and uniform magnetic nanoparticles [8,10]. Superparamagnetic iron-platinum particles (SIPPs) produced using such methods are seen to maintain their relative stability in solutions [2,8,9].…”

“…A fourth component of the reaction is the use of fatty amines and fatty acids as ligands. Fatty amines, in the form of octadecylamine (ODA), are carbon-18 single chain fatty amines that play a critical role in the stabilization of the nanocrystal in the early stages of synthesis [10]. Moreover, fatty amines can act as both the solvent and the ligand, reducing the number of chemicals needed to produce the alloy nanocrystals.…”