Bicomponent dendritic macromolecules: design and assembly of multifunctional nanomaterials

这一建议旨在构建定义良好的大分子异质结构，并探索它们协同高效地执行多种预定功能的潜力。这些平台可以提供个人和特色功能的协同组合，使它们在包括传感器、识别/传送工具和催化在内的各种领域具有相关性。这些组成各异的树枝状大分子文库的简单性的关键是氨基锡烷对乙炔的化学选择性。从具有两个不同焦点群的中心核心开始，它将允许使用氨基硅烷有效地建立一只手臂，然后使用氨基锡烷向外建立第二个壳层结构。这种方法的多功能性提供了引入各种树状结构的可能性，这些结构具有针对所需功能的定制的主干组合。对这些双嵌段树枝状大分子自组织的详细了解将在溶液和界面上进行广泛的研究，这将为获得具有局部功能密度区域的新型组装提供一种便捷的途径。本方案中开发的树枝状大分子将用于制备各种尺寸和形状可控的金属纳米颗粒。空间定义的多金属体系将使用双功能树枝状大分子组装，是设计合作催化剂的极佳候选者，可以在一个锅中进行多个有机转化。此外，我们将探索将这些树枝状大分子的一块自组装成离散的形状，然后使用第二个臂在所产生的预定位置合成纳米颗粒。这提供了一种相对简单的超分子方法来制备形貌可控的纳米结构，这对于定制它们的独特行为是必不可少的。这一提议的更广泛影响是建立关于多组分产品的累积知识库，这将在组装各种纳米级结构方面极其有用，并将解决化学和材料科学中的关键问题。

This proposal aims at constructing well defined macromolecular heterostructures, and explores their potential in performing multiple predetermined functions, cooperatively and efficiently. These platforms that can provide a synergistic combination of individual and characteristic functionalities, makes them of relevance in a variety of areas including sensors, recognition/delivery vehicles and catalysis. The key to simplicity with which a library of these compositionally diverse dendrimers will be delivered, is the chemoselectivity of amino-stannanes towards acetylenes. Starting from a central core with two distinct focal groups, it will allow efficient build-up of one arm using aminosilanes, followed by second shell hierarchy outward using aminostannanes. The versatility of the approach offers the potential to introduce a variety of dendron structures with a tailored combination of backbones for desired functions. A detailed understanding of the self-organization of these diblock dendrimers that will be investigated extensively in solution and at interfaces, will provide a facile access to novel assemblies with regions of localized functional density. Dendrimers developed in this proposal will be used to fabricate a variety of size and shape controlled metallic nanoparticles. The spatially defined multimetallic systems that will be assembled using bifunctional dendrimers, are excellent candidates in designing co-operative catalysts that can carry out multiple organic transformations in a single pot. In addition, we shall explore self-assembly of a block of these dendrimers into discrete shapes, and then employ the second arm to synthesize nanoparticles at the resulting pre-determined positions. This provides a relatively simple supramolecular approach to fabricate morphologically controlled nanostructures which is essential for tailoring their unique behavior. The broader impact of this proposal is to build cumulative knowledge base on multi-component products, which will be extremely useful in assembling a wide variety of nanoscale structures, and will address key issues in chemistry and materials science.