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Solvent-dependent host-guest chemistry of polyhedral coordination cages

多面体配位笼的溶剂依赖性主客体化学

基本信息

批准号：
EP/H043195/1
负责人：
Mike Ward
金额：
$ 82.83万
依托单位：
University of Sheffield
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2010
资助国家：
英国
起止时间：
2010 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FH043195%2F1
关键词：
Solvent dependent host guest chemistry

项目摘要

Polyhedral coordination cages are hollow, capsule-like complexes available in a range of shapes and sizes according to the nature of the metal ion and ligand used to prepare them; examples are known with structures such as tetrahedral, cubic, truncated tetrahedral and cuboctahedral. An appealing feature of them is that they have a central cavity which is capable of accommodating guest species of various shapes and sizes. These guests may be anions (as the cages are positively charged) or, in predominantly aqueous solvents, neutral organic molecules which prefer the hydrophobic interior of the cage to the polar exterior for which they have less affinity.We plan to prepare a new series of these cages that contain inwardly-directed functional groups so that we can systematically change the internal environment of the cages by altering the spatial arrangement and nature of the groups lining the central cavity that will interact with different guest species. This will change the affinity the cage 'hosts' for different guests. By systematically varying the host cages, and the cavity shape/size and arrangement of functional groups in the guests, it will be possible to analyse the factors that are responsible for effective binding of guests by the hosts in a range of solvents, of which water is the most important. Understanding of molecular recognition in aqueous systems is one of the outstanding unsolved problems in chemistry that would have a major impact in other fields, like biology and medicine, where issues such as drug/receptoy interactions and protein folding are all based on recognition between simple molecular components in aqueous media.Having identified well-fitting guests for different cage hosts, and analysed the factors responsible for the strong binding, it should be possible to use these guests as 'templates' to control assembly of cages around them. This may lead to new types of cage if a particular guest selects a particular combination of ligands that had not previously been investigated, or it may lead to known cages assembling much more quickly because of the action of the guest in pulling the components together.Finally, we will exploit the fact that many of the cages are fluorescent because of the presence of fluorescent groups in the ligands used to prepare them. Transfer of excitation energy from a host cage molecule - after absorption of light - to a trapped guest will be investigated, and if possible we will use this phenomenon to trigger isomerisation reactions in the guest. Thus, a guest molecule will enter a host cavity, and shining light on the cage will result in energy transferred to the guest which then undergoes reaction. the host cage therefore acts as a 'photochemical microreactor', both binding the guest and supplying the energy necessary for it to undergo a reaction.

多面体配位笼是中空的胶囊状复合物，根据用于制备它们的金属离子和配体的性质，有多种形状和尺寸可供选择；已知的结构例如四面体、立方体、截顶四面体和立方八面体的例子。它们的一个吸引人的特点是它们有一个中心空腔，能够容纳各种形状和大小的客体物种。这些客体可能是阴离子（因为笼子带正电荷），或者在主要是水性溶剂中的中性有机分子，它们更喜欢笼子的疏水内部，而不是亲和力较小的极性外部。我们计划制备一系列新的笼子，其中包含向内定向的官能团，以便我们可以通过改变笼子的空间排列和性质来系统地改变笼子的内部环境。排列在中央空腔内的群体将与不同的客体物种相互作用。这将改变笼子“接待”不同客人的亲和力。通过系统地改变宿主笼、空腔形状/大小以及客体中官能团的排列，将可以分析导致宿主在一系列溶剂中有效结合客体的因素，其中水是最重要的。对水性系统中分子识别的理解是化学中尚未解决的突出问题之一，这将对其他领域产生重大影响，例如生物学和医学，其中药物/受体相互作用和蛋白质折叠等问题都是基于水性介质中简单分子成分之间的识别。在确定了适合不同笼宿主的客体并分析了导致强结合的因素后，应该可以将这些客体用作 “模板”来控制周围笼子的组装。如果特定客体选择了以前未研究过的特定配体组合，这可能会导致新型笼的产生，或者由于客体将组件拉到一起的作用，可能会导致已知的笼更快地组装。最后，我们将利用这样一个事实，即许多笼是荧光的，因为用于制备它们的配体中存在荧光基团。我们将研究吸收光后激发能量从宿主笼分子转移到被捕获的客体的情况，如果可能的话，我们将利用这种现象来触发客体中的异构化反应。因此，客体分子将进入主体空腔，并且将光照射到笼上将导致能量转移到客体，然后发生反应。因此，宿主笼充当“光化学微反应器”，既结合客体又提供其发生反应所需的能量。