Understanding mercapto ligand exchange on the surface of FePt nanoparticles
Understanding mercapto ligand exchange on the surface of FePt nanoparticles
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DOI：
10.1021/la0601399
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发表时间：
2006-08-29
期刊：
影响因子：
3.9
通讯作者：
Johnson, Duane T.
中科院分区：
文献类型：
--
作者：
Bagaria, Hitesh G.;Ada, Earl T.;Johnson, Duane T.
纳米粒子的表面修饰对于磁性纳米粒子的生物应用至关重要。FePt纳米颗粒由于其高磁矩而成为令人感兴趣的候选者。已建立的制备FePt纳米颗粒的方法使用油酸和油胺作为表面活性剂，使它们分散在非极性溶剂如己烷中。作为一个模型研究，以证明表面化学的改性，稳定的水性分散体的FePt纳米粒子与巯基链烷酸的配体交换后合成。本报告的重点是通过X射线光电子能谱（XPS）和傅里叶变换红外光谱（FTIR）研究，了解FePt与巯基化合物进行配体交换后的表面化学。发现巯基末端置换Pt原子上的油胺，羧酸末端置换Fe原子上的油酸，从而暴露表面上的羧酸根和硫醇根基团，其提供必要的静电排斥以形成FePt纳米颗粒的稳定水性分散体。
Tailoring the surface of nanoparticles is essential for biological applications of magnetic nanoparticles. FePt nanoparticles are interesting candidates owing to their high magnetic moment. Established procedures to make FePt nanoparticles use oleic acid and oleylamine as the surfactants, which make them dispersed in nonpolar solvents such as hexane. As a model study to demonstrate the modification of the surface chemistry, stable aqueous dispersions of FePt nanoparticles were synthesized after ligand exchange with mercaptoalkanoic acids. This report focuses on understanding the surface chemistry of FePt upon ligand exchange with mercapto compounds by conducting X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) studies. It was found that the mercapto end displaces oleylamine on the Pt atoms and the carboxylic acid end displaces the oleic acid on the Fe atoms, thus exposing carboxylate and thiolate groups on the surface that provide the necessary electrostatic repulsion to form stable aqueous dispersions of FePt nanoparticles.