Chiral nanostructures have been attracting extensive interest in recent years primarily because of the unique materials properties that can be exploited for diverse applications. In this study, gold Janus nanoparticles, with hexanethiolates and 3-mercapto-1,2-propanediol segregated on the two hemispheres of the metal cores (dia. 2.7 ± 0.4 nm), self-assembled into vesicle-like, hollow nanostructures in both water and organic media, and exhibited apparent plasmonic circular dichroism (PCD) absorption in the visible range. This was in contrast to individual Janus nanoparticles, bulk-exchange nanoparticles where the two ligands were homogeneously mixed on the nanoparticle surface, or nanoparticles capped with only one kind of ligand. The PCD signals were found to become intensified with increasing coverage of the 3-mercapto-1,2-propanediol ligands on the nanoparticle surface. This was accounted for by the dipolar property of the structurally asymmetrical Janus nanoparticles, and theoretical simulations based on first principles calculations showed that when the nanoparticle dipoles self-assembled onto the surface of a hollow sphere, a vertex was formed which gave rise to the unique chiral characteristics. The resulting chiral nanoparticle vesicles could be exploited for the separation of optical enantiomers, as manifested in the selective identification and separation of D-alanine from the L-isomer.

中文翻译：

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通过非模板性手性Janus纳米粒子的无模板自组装，使囊状纳米结构的等离子圆二色性†

近年来，手性纳米结构吸引了广泛的兴趣，这主要是由于可以用于多种应用的独特材料特性。在这项研究中，金Janus纳米粒子在金属核的两个半球（直径2.7±0.4 nm）上分离出具有己硫醇盐和3-巯基1,2-丙二醇的纳米粒子，并自组装成两个囊泡状的空心纳米结构水和有机介质，并在可见光范围内表现出明显的等离子体圆二色性（PCD）吸收。这与单独的Janus纳米颗粒，本体交换纳米颗粒（其中两个配体均匀混合在纳米颗粒表面上）或仅用一种配体封端的纳米颗粒形成对比。人们发现，随着3-mercapto-1覆盖率的增加，PCD信号会增强，纳米颗粒表面上的2-丙二醇配体。这是由于结构上不对称的Janus纳米粒子的偶极特性引起的，基于第一性原理计算的理论模拟表明，当纳米粒子偶极子自组装到空心球表面时，形成了一个顶点，从而产生了独特的手性特征。所得手性纳米颗粒囊泡可用于光学对映体的分离，如选择性鉴定和分离 形成了一个顶点，从而产生了独特的手性特征。所得手性纳米颗粒囊泡可用于光学对映体的分离，如选择性鉴定和分离 形成了一个顶点，从而产生了独特的手性特征。所得手性纳米颗粒囊泡可用于光学对映体的分离，如选择性鉴定和分离来自L-异构体的D-丙氨酸。