Kumar Ashavani, Mandal Saikat, Selvakannan P R, Pasricha Renu, Mandale A B, Sastry Murali
Materials Chemistry Division, National Chemical Laboratory, Pune 411 008, India.
Langmuir. 2003 Jul 22;19(15):6277-6282. doi: 10.1021/la034209c.
In addition to alkanethiols and phosphine derivatives, alkylamines have been investigated as capping agents in the synthesis of organically dispersible gold nanoparticles. However, reports pertaining to gold nanoparticle derivatization with alkylamines are relatively scarce and their interaction with the underlying gold support is poorly understood. In this paper, we attempt a more detailed examination of this problem and present results on the Fourier transform infrared spectroscopy, thermogravimetry, nuclear magnetic resonance, and X-ray photoemission (XPS) characterization of gold nanoparticles capped with the alkylamines laurylamine (LAM) and octadecylamine (ODA). The capping of the gold nanoparticles with the alkylamines was accomplished during phase transfer of aqueous gold nanoparticles to chloroform containing fatty amine molecules. Thermogravimetry and XPS analysis of purified powders of the amine-capped gold nanoparticles indicated the presence of two different modes of binding of the alkylamines with the gold surface. The weakly bound component is attributed to the formation of an electrostatic complex between protonated amine molecules and surface-bound AuCl/AuCl ions, while the more strongly bound species is tentatively assigned to a complex of the form [AuCl(NHR)]. The alkylamine monolayer on the gold nanoparticle surface may be place exchanged with other amine derivatives present in solution.
除了链烷硫醇和膦衍生物外，烷基胺已被研究用作合成有机分散金纳米颗粒的封端剂。然而，关于用烷基胺对金纳米颗粒进行衍生化的报道相对较少，并且它们与底层金载体的相互作用也了解甚少。在本文中，我们尝试对这个问题进行更详细的研究，并给出了用月桂胺（LAM）和十八烷基胺（ODA）封端的金纳米颗粒的傅里叶变换红外光谱、热重分析、核磁共振和X射线光电子能谱（XPS）表征结果。在用烷基胺对金纳米颗粒进行封端的过程中，是在将水基金纳米颗粒转移至含有脂肪胺分子的氯仿相中完成的。对胺封端的金纳米颗粒纯化粉末进行的热重分析和XPS分析表明，烷基胺与金表面存在两种不同的结合模式。弱结合组分归因于质子化胺分子与表面结合的AuCl/AuCl离子之间形成的静电络合物，而结合更强的物种初步被认为是[AuCl(NHR)]形式的络合物。金纳米颗粒表面的烷基胺单层可能会与溶液中存在的其他胺衍生物发生配体交换。
