Supramolecular Dynamics in Solution and in Gels

就复杂性和功能性而言，超分子化学占据了个体分子和宏观系统之间的空间。超分子系统的两个关键特征是：1)由分子构建块可逆组装成一个超分子；2)相互竞争的相关物种共存。这些特征是在非常复杂的宏观生命系统中所表现出来的。我的研究旨在了解超分子系统的动力学性质，并从动力学的角度为合理控制这些系统提供必要的概念。这种目前缺乏的动力学控制将为设计功能材料开辟新的途径，其中组件的动力学对功能至关重要。提出的研究处于基础研究的前沿，并不直接解决任何特定的功能，但其结果对任何超分子系统都有影响，其中构建块的结合和释放是功能的组成部分，例如膜运输，药物传递，催化或刺激反应材料。这项拟议中的研究与“系统化学”有关，在系统化学中，分子构建块的相互作用产生了单个组分无法单独实现的新特性。为了开发和利用固有的复杂系统，我们需要开发工具来探索和操纵系统的结果。提出的工作面对超分子系统的多样性，重点是凝胶形成系统的动力学控制。***建议使用葫芦[n]urils （CB[n]s）作为宿主系统，将提供操纵主客系统动态的工具。这些知识将为合理地利用动力学来改变多物种系统的行为奠定基础，这在目前是不可能的。我们发现的客体与CB[n]s结合的机制多样性将被探索，以确定共佐剂如何导致机制的切换，自分类系统如何随着它们的进化而改变，以及同时与CB[8]结合的客体的停留时间如何影响凝胶的形成。***将在微观到宏观的长度尺度上研究凝胶中的小客体的流动性，以提供关于凝胶分子成分的信息。这种方法将揭示与通常报道的凝胶宏观表征不同的知识。这类实验的重点是单个组分的动力学以及与凝胶微观结构特征的关系，这是前所未有的。作为潜在的实际应用，所提出的工作将有助于将凝胶的开发从试验和错误的方法中转移出来。

Supramolecular chemistry occupies the space between individual molecules and macroscopic systems in terms of complexity and functionality. Two key features of supramolecular systems are: 1) the reversible assembly of a supermolecule from molecular building blocks and 2) the co-existence of related species that compete with one another. These characteristics are those exhibited in very complex macroscopic living systems. My research aims to understand the dynamic nature of supramolecular systems and will provide the concepts necessary for rational control of these systems from the kinetic point of view. Such kinetic control, which is currently lacking, will open new ways to design functional materials, where the dynamics of the components are essential for function. The research proposed is at the forefront of fundamental studies and does not directly address any particular function, but the outcomes have implications for any supramolecular system where binding and release of building blocks is integral to function, such as membrane transport, drug delivery, catalysis, or stimuli-responsive materials. The proposed research is allied with “systems chemistry”, in which interactions of molecular building blocks produce new properties that the individual components cannot achieve on their own.***To develop and exploit inherently complicated systems, we need to develop tools to explore and manipulate the system's outcomes. The proposed work confronts the diversity of supramolecular systems, with a focus on the kinetic control of gel-forming systems.***The proposed work with cucurbit[n]urils (CB[n]s) as host systems will provide the tools to manipulate the dynamics of host-guest systems. This knowledge will lay the groundwork for rationally using kinetics to change the behaviour of systems with multiple species, which currently is not possible. The mechanistic diversity we uncovered for guest binding with CB[n]s will be explored to determine how co-adjuvant players can lead to switches in mechanism, how self-sorting systems can be diverted as they evolve, and how the residence time of guests that simultaneously bind to CB[8] can affect the formation of gels.***The mobility of small guests in gels will be studied over microscopic to macroscopic length scales to provide information focused on the gel's molecular components. This approach will uncover knowledge that is different from the macroscopic characterization usually reported for gels. This type of experiment, where the focus is on the kinetics of individual components and the relationship to the microscopic structural features of gels, is unprecedented. As a potential practical application, the proposed work will contribute to moving the development of gels away from a trial and error approach.