Wulandari Priastuti, Nagahiro Takeshi, Fukada Nobuko, Kimura Yasuo, Niwano Michio, Tamada Kaoru
Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan; Department of Physics, Institut Teknologi Bandung, Jalan Ganesha 10, Bandung 40132, Indonesia.
Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
J Colloid Interface Sci. 2015 Jan 15;438:244-248. doi: 10.1016/j.jcis.2014.09.078. Epub 2014 Oct 13.
In this paper, we report different coordinations of citrates on gold (AuNP) and silver (AgNP) nanoparticles, as determined using Fourier transform infrared spectroscopy (FTIR) and molecular orbital (MO) calculations. AuNPs and AgNPs are found to have completely different interactions with the carboxylate anchoring groups, as indicated by their unique asymmetric stretching vibrations in the FTIR spectra. The ν(as) (COO(-)) of citrate exhibits a high-frequency shift resulting from the formation of a unidentate coordination on AuNPs, whereas this vibration exhibits a low-frequency shift as a result of ionic bond formation on AgNPs, as predicted from the MO calculations of the corresponding metal complex salts. The enhancement in the IR signals when their vibration direction was perpendicular to the nanoparticle surface revealed the influence of localized surface plasmons excited on the metal nanoparticles.
在本文中，我们报告了通过傅里叶变换红外光谱（FTIR）和分子轨道（MO）计算确定的柠檬酸盐在金（AuNP）和银（AgNP）纳米颗粒上的不同配位情况。FTIR光谱中独特的不对称伸缩振动表明，AuNP和AgNP与羧酸根锚定基团具有完全不同的相互作用。柠檬酸盐的ν(as)(COO(-))由于在AuNP上形成单齿配位而呈现高频位移，而根据相应金属络合盐的MO计算预测，该振动由于在AgNP上形成离子键而呈现低频位移。当它们的振动方向垂直于纳米颗粒表面时，IR信号增强，这揭示了金属纳米颗粒上激发的局域表面等离子体的影响。
