Guo Chengchen, Yarger Jeffery L
School of Molecular Sciences, Magnetic Resonance Research Center, Arizona State University, Tempe, AZ, 85287-1604.
Magn Reson Chem. 2018 Nov;56(11):1074-1082. doi: 10.1002/mrc.4753. Epub 2018 Jun 19.
Gold nanoparticles have attracted considerable attention in recent research because of their wide applications in various fields such as material science, electrical engineering, physical science, and biomedical engineering. Researchers have developed many methods for synthesizing different kinds of gold nanoparticles, where the sizes and surface chemistry of the nanoparticles are considered to be the two key factors. Traditionally, the sizes of nanoparticles are determined by electron microscopy whereas the surface chemistry is characterized by optical spectroscopies such as infrared spectroscopy and Raman spectroscopy. Compared with that, nuclear magnetic resonance (NMR) spectroscopy provides a more advanced and convenient way for size determination and surface chemistry investigations by combining one- and multiple-dimensional NMR spectroscopy and diffusion-order NMR spectroscopy. Here, we show a thorough study that NMR spectroscopy can be applied to characterize small thiol-protected gold nanoparticles, including size determination, surface chemistry investigation, and structural study. The results show that the nanoparticles' sizes determined by NMR agree well with transmission electron microscopy results. Furthermore, the ligand densities of nanoparticles were determined by quantitative NMR spectroscopy, and the structures of ligands capped on the surfaces were studied thoroughly by one- and multiple-dimensional NMR spectroscopy. In this work, we establish a general method for researchers to characterize nanostructures by using NMR spectroscopy.
金纳米颗粒因其在材料科学、电气工程、物理科学和生物医学工程等各个领域的广泛应用，在最近的研究中引起了相当大的关注。研究人员已经开发出许多合成不同种类金纳米颗粒的方法，其中纳米颗粒的尺寸和表面化学被认为是两个关键因素。传统上，纳米颗粒的尺寸通过电子显微镜测定，而表面化学则通过红外光谱和拉曼光谱等光学光谱进行表征。与之相比，核磁共振（NMR）光谱通过结合一维和多维NMR光谱以及扩散排序NMR光谱，为尺寸测定和表面化学研究提供了一种更先进、更便捷的方法。在此，我们展示了一项深入研究，即NMR光谱可用于表征小的硫醇保护的金纳米颗粒，包括尺寸测定、表面化学研究和结构研究。结果表明，通过NMR测定的纳米颗粒尺寸与透射电子显微镜结果吻合良好。此外，通过定量NMR光谱测定了纳米颗粒的配体密度，并通过一维和多维NMR光谱对包覆在表面的配体结构进行了深入研究。在这项工作中，我们为研究人员建立了一种利用NMR光谱表征纳米结构的通用方法。
