Dendrimer-Encapsulated Metal Nanoparticles

在这个由分析和表面化学计划支持的项目中，德克萨斯A M大学的Richard Crooks教授和同事将合成和表征树枝状聚合物封装的金属颗粒。 这些材料的潜在优点是方便地获得纳米尺寸的金属颗粒，在1-3纳米的数量级，具有高的单分散性和良好的稳定性。 这些纳米材料将通过两步法制备。 首先，将树枝状聚合物暴露于含金属离子的溶液。 这导致金属离子和树枝状聚合物内的配体之间的络合。 第二步涉及有机/无机复合物的化学还原，这导致形成树枝状聚合物内金属纳米颗粒。 每个树枝状聚合物充当离散的纳米反应器，并且只有树枝状聚合物内的那些金属离子聚结到所得的纳米颗粒中。 这意味着原则上每个纳米颗粒都包含相同数量的金属原子。 这是重要的，因为目前很少有方法可用于制备在1-3 nm尺寸范围内的单分散金属金属簇，其既具有表面活性又可溶于许多溶剂中。 这个尺寸范围是有趣的，原因有很多，但主要是因为它是金属原子从原子性质到金属性质转变的范围。 单分散金属纳米粒子在技术领域有许多应用。应用包括电子学、生物医学应用、催化的基础研究以及化学和生物传感器。 除了这些更广泛的影响，这项工作邀请许多合作研究项目。 树枝状聚合物封装的金属颗粒的催化性能将由Trinity大学的同事进行评估。 商业应用将与密歇根分子研究所的同事一起进行评估。 纳米粒子的其他表征将在韩国进行同步加速器实验。最后，该提案将支持当地高中生和本科生在夏季从事该项目。

In this project supported by the Analytical and Surface Chemistry Program, Professor Richard Crooks and coworkers at Texas A&M University will synthesize and characterize dendrimer-encapsulated metal particles. The potential advantage of these materials is convenient access to nanometer-sized metal particles, on the order of 1-3 nanometers, having both high monodispersity and good stability. These nanomaterials are to be prepared by a two step process. First, the dendrimer is exposed to a metal ion-containing solution. This results in complexation between the metal ions and ligands within the dendrimer. The second step involves chemical reduction of the organic/inorganic composite, which results in formation of an intradendrimer metal nanoparticle. Each dendrimer acts as a discreet nanoreactor, and only those metal ions within the dendrimer coalesce into the resulting nanoparticle. This means that in principle every nanoparticle will contain the same number of metal atoms. This is significant because at the present time there are few methods available for preparing monodisperse metallic metal clusters in the 1-3 nm size range that are both surface active and soluble in many solvents. This size range is interesting for a number of reasons, but mainly because it is the range over which metal atoms undergo a transition from atomic to metallic properties. Monodispersed metal nanoparticles have many applications to the technology sector. Applications include electronics, biomedical applications, fundamental studies of catalysis, and chemical and biological sensors. In addition to these broader impacts, this work invites many collaborative research projects. Catalytic properties of the dendrimer-encapsulated metal particles will be evaluated by colleagues at Trinity University. Commercial applications will be evaluated with colleagues at the Michigan Molecular Institute. Additional characterization of the nanoparticles is to be done with synchrotron experiments to be performed in South Korea. Finally, this proposal will support local high school students and undergraduates to work on the project during the summers.