Assessment of 4-(dimethylamino)pyridine as a capping agent for gold nanoparticles
Assessment of 4-(dimethylamino)pyridine as a capping agent for gold nanoparticles
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DOI：
10.1021/la050195u
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发表时间：
2005-07-05
期刊：
影响因子：
3.9
通讯作者：
Lennox, RB
中科院分区：
文献类型：
--
作者：
Gandubert, VJ;Lennox, RB
通过配体交换和相转移（甲苯/水）法制备了以4-（二甲氨基）吡啶（DMAP）为稳定剂的功能化金纳米粒子。DMAP保护的金纳米颗粒是水溶性的，带正电荷，并且相当单分散（6.2 +/- 0.9 nm）。为了理解这个有趣的系统的范围，研究了DMAP与金纳米颗粒结合的细节。用电化学和表面等离子体共振研究了DMAP在金表面的吸附。可以得出结论，在三种最可能的结合模式中，如先前所建议的，涉及吡啶氮结合到金表面的模式（Gittins，D.一、Caruso，F. Angew.化学成分：Int.Ed.2001，40，3001），与实验数据一致。其他4-取代的吡啶也被评估为封端剂。引入的配体在甲苯中的溶解度和碱性，以及形成带电纳米颗粒的能力，决定了是否发生配体交换和随后的纳米颗粒相转移。利用紫外-可见光谱和透射电子显微镜（TEM）研究了DMAP保护的金纳米粒子的溶解度和稳定性随pH的变化。这些纳米颗粒在宽pH范围（5.0-12.8）内是可溶的和稳定的。结果发现，过量的DMAP是必要的制备和DMAP保护的金纳米粒子的稳定性。
Gold nanoparticles stabilized with 4-(dimethylamino)pyridine (DMAP) were prepared by ligand exchange and phase transfer (toluene/water) of functionalized gold nanoparticles. DMAP-protected gold nanoparticles are water-soluble, positively charged, and fairly monodisperse (6.2 +/- 0.9 nm). To understand the scope of this interesting system, the details of the binding of DMAP to gold nanoparticles were investigated. The adsorption of DMAP onto gold surfaces was studied by electrochemistry and surface plasmon resonance. It is concluded that of the three most likely binding modes, the one involving the pyridine nitrogen binding to the gold surface, as suggested previously (Gittins, D. I.; Caruso, F. Angew. Chem., Int. Ed. 2001, 40, 3001), is consistent with experimental data. Other 4-substituted pyridines were also assessed as capping agents. The solubility in toluene and basicity of the incoming ligand, as well as the ability to form charged nanoparticles, determine whether ligand exchange and subsequent phase transfer of the nanoparticles occur. The solubility and stability of the DMAP-protected gold nanoparticles were studied as a function of pH using UV-visible spectroscopy and transmission electron microscopy (TEM). These nanoparticles are soluble and stable over a wide pH range (5.0-12.8). It was found that excess DMAP is necessary for both the preparation and the stability of the DMAP-protected gold nanoparticles.