Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland.
Chemistry. 2011 Nov 25;17(48):13473-81. doi: 10.1002/chem.201101837. Epub 2011 Oct 26.
Ligand-stabilized gold nanoparticles (Au NPs) are promising materials for nanotechnology with applications in electronics, catalysis, and sensors. These applications depend on the ability to synthesize stable and monodisperse NPs. Herein, the design and synthesis of two series of dendritic thioether ligands and their ability to stabilize Au NPs is presented. The dendrimers have 1,3,5-trisubstituted benzene branching units bridged by either meta-xylene or ethylene moieties. A comparison between the two ligands shows how both size control and the stability of the NPs are influenced by the nature of the ligand-NP wrapping interaction. The meta-xylene-bridged ligands provided NPs with a narrow size distribution centered around a diameter of 1.2 nm, whereas the NPs formed with ethylene-bridged dendrimers lack long-term stability with NP aggregation detected by UV/Vis spectroscopy and transmission electron microscopy. The bulkier tert-butyl-functionalized meta-xylene bridges form larger ligand shells that inhibit further growth of the NPs and thus provide a simple route to stable and monodisperse Au NPs that may find use as functional components in nanoelectronic devices.
配体稳定的金纳米粒子 (Au NPs) 是一种有前途的纳米技术材料，可应用于电子、催化和传感器等领域。这些应用依赖于合成稳定且单分散的 NPs 的能力。本文介绍了两种系列树枝状硫醚配体的设计和合成及其稳定 Au NPs 的能力。这些树状大分子具有由间二甲苯或乙烯单元桥接的 1,3,5-三取代苯支化单元。两种配体的比较表明，配体-NP 包裹相互作用的性质如何影响 NPs 的尺寸控制和稳定性。间二甲苯桥联配体提供的 NPs 具有 1.2nm 左右的窄粒径分布，而用乙烯桥联树状大分子形成的 NPs 缺乏长期稳定性，通过紫外/可见光谱和透射电子显微镜检测到 NP 聚集。体积较大的叔丁基功能化的间二甲苯桥形成更大的配体壳，抑制 NPs 的进一步生长，从而提供了一种简单的方法来制备稳定且单分散的 Au NPs，它们可能作为纳米电子器件中的功能组件得到应用。
