Fluorescence investigations of supramolecular systems

超分子结构由两个或多个分子组成，这些分子仅通过相对较弱的分子间吸引力结合在一起。一个简单的例子是主体-客体包合复合物，其中“客体”分子被包含在更大的笼状“主体”分子的空腔内，就像桶中的球。这种结构可以令人惊讶地坚固，尽管缺乏真正的化学键将组分保持在一起，并且具有许多应用。例如，如果主体可溶于水，这可以使原本不溶的客体可溶。例如，这可以允许改进的药物递送。这种系统也可以用作分子传感器，当目标分子存在时，它会发出某种信号。研究这种系统的最佳方法之一是使用荧光光谱。荧光是某些分子在其电子被激发（获得多余能量）时发出的光，例如在吸收光（路标）或电（荧光灯）之后。当分子组分形成超分子结构时，其荧光性质发生显著变化，为研究其形成、性质和结构提供了一种高灵敏度和准确度的方法。该提案涉及使用荧光来研究和表征超分子体系的各种方法。我们的小组已经做了大量的工作，使用荧光客人在非荧光主机。我们使用的宿主包括类似于分子桶和分子南瓜的分子。在这个提议中，感兴趣的新领域之一是荧光宿主的研究。这很重要，因为它允许研究任何感兴趣的客体，而不要求它是荧光的。我们建议使用这样的荧光主机作为积木，它可以连接在一起使用适当的双头客人给广泛的超分子结构，如分子修补匠。由于这些结构将是荧光的，它们可能具有广泛的有用应用，包括作为荧光分子传感器，其在特定物质的存在下打开或关闭。

Supramolecular structures consist of two or more molecules held together only by relatively weak intermolecular forces of attraction. One simple example is a host-guest inclusion complex, in which a "guest" molecule becomes included within the cavity of a larger, cage-like "host" molecule, like a ball in a bucket. Such structures can be surprisingly robust, despite the lack of true chemical bonds holding the components together, and have numerous applications. For example, if the host is soluble in water, this can make otherwise insoluble guests soluble. This can allow for improved drug delivery, for example. Such systems can also be useful as molecular sensors, which give some sort of a signal when a target molecule is present. One of the best ways to study such systems is using fluorescence spectroscopy. Fluorescence is the light that certain molecules emit when their electrons are excited (gain excess energy), for example after absorbing light (road signs), or by electricity (fluorescent lights). The fluorescence of the molecular components can undergo significant changes when they form supramolecular sturctures, providing a hihgly sensitive and accurate method for studying their formation, properties, and structures. This proposal involves various ways of using fluorescence to study and characterize supramolecular systems. Our group has done extensive work using fluorescent guests in non-fluorescent hosts. The hosts we have used include molecules which resemble molecular buckets and molecular pumpkins. In this proposal, one of the new areas of interest is the study of fluorescent hosts. This is important, as it allows for the study of any guest of interest, with no requirement for it to be fluroescent. We are proposing the use of such fluorescent hosts as building blocks, which can be joined together using appropriate double-headed guests to give extensive supramolecular structures, like molecular Tinkertoy. Since these structures will be flourescent, they could have a wide range of useful applications, including as fluorescent molecular sensors which turn on or off in the presence of particular substances.