Utilizing the amidation reaction to address the “cooperative effect” of carboxylic acid/amine on the size, shape, and multicolor output of fluoride upconversion nanoparticles
Utilizing the amidation reaction to address the “cooperative effect” of carboxylic acid/amine on the size, shape, and multicolor output of fluoride upconversion nanoparticles
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DOI：
10.1039/c1jm10985e
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发表时间：
2011-07
影响因子：
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通讯作者：
W. Niu;Suli Wu;Shufen Zhang
中科院分区：
文献类型：
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作者：
W. Niu;Suli Wu;Shufen Zhang
在这里，我们阐明了羧酸/胺的大小，形状和氟化物上转换纳米粒子（UCNPs）利用酰胺化反应的“协同效应”。在使用油酸（OA）和十八胺（OM）作为配体合成NaYF 4 UCNPs的过程中，通过FT-IR和质子核磁共振（1H-NMR）光谱监测反应溶液的演变。结果表明，N-十八烷基油酰胺（OOA）形成并紧密结合到氟UCNPs的表面。FT-IR和1H-NMR分析表明，OOA的形成机制为两步式，即OA首先与OM反应，在反应混合物中形成酸碱复合物（C17 H33 CO2 − + NH3 C18 H37），在高温下氟化物UCNP成核之前，该复合物进一步转化为OOA。重要的是，我们发现OOA与氟化物UCNPs表面的相互作用比OM强，并且OOA可以强烈地淬灭激发的Er 3+离子的绿光发射水平。一系列的控制实验和分析表明，OOA不仅负责控制NaYF_4：20%Yb，2%Er UCNPs的尺寸和形状，而且还负责对它们进行微调。这些结果表明，羧酸和胺之间的“协同效应”是酰胺化反应及其产物的结果。本文对羧酸和胺在热合成无机纳米粒子过程中的“协同效应”提供了一些新的见解。此外，还可以以相同的方式获得具有受控的尺寸、形状和纳米级输出的其他镧系元素离子掺杂的氟化物UCNP。
Here we elucidate the “cooperative effect” of carboxylic acid/amine on the size, shape, and multicolor output of fluoride upconversion nanoparticles (UCNPs) utilizing the amidation reaction. During the synthesis of NaYF4 UCNPs using oleic acid (OA) and octadecylamine (OM) as ligands, the evolution of the reaction solution was monitored by FT-IR and proton nuclear magnetic resonance (1H-NMR) spectroscopy. It is shown that N-octadecyloleamide (OOA) was formed and tightly bonded to the surface of the fluoride UCNPs. FT-IR and 1H-NMR analyses point towards a two-step OOA formation mechanism where OA initially reacted with OM to form an acid–base complex (C17H33CO2− +NH3C18H37) in reaction mixture, which further transformed into OOA before the nucleation of fluoride UCNPs at elevated temperature. Importantly, we find that the interaction of OOA with the surfaces of the fluoride UCNPs was stronger than that of OM, and that OOA could strongly quench the green-emitting levels of excited Er3+ ions. A series of control experiments and analyses demonstrate that OOA was not only responsible for the control of the size and shape of NaYF4: 20% Yb, 2% Er UCNPs, but also for the multicolor tuning of them. Those observations reveal that the “cooperative effect” between carboxylic acid and amine results from the amidation reaction and its product. This paper provides us with some new deep insights into the “cooperative effect” of carboxylic acid and amine during the synthesis of inorganic nanoparticles under thermolysis. Furthermore, other lanthanide-ion doped fluoride UCNPs with controlled size, shape and multicolor output can also be obtained in the same way.