Matrix-Assisted DOSY

核磁共振（NMR）光谱是化学家最广泛使用的确定未知化合物分子结构的单一工具。它是一种非常通用和灵敏的工具，但它有一个主要缺点：它在分析混合物方面很差，所以它主要用于仔细纯化的单一化合物。由于自然界中许多最具挑战性的问题--以及合成化学家和工业界提出的许多问题--都是以混合物的形式呈现给我们的，因此我们花费了大量的努力将混合物分离成单独的组分，以便能够识别它们。扩散有序光谱（DOSY）试图通过分离不同分子的NMR信号来克服这一限制，从而可以区分来自不同物种的信号。在过去的十年里，我们的研究小组和其他人开发了这项技术，并成功地应用了它-但几乎总是简单的解决方案。在该项目中，博士后研究员将研究通过向溶剂中添加表面活性剂（肥皂和洗涤剂的活性成分），凝胶和可溶性聚合物等物质来更有效地分离混合物组分的光谱，以制备改变分子扩散方式的溶液（基质）。这些物质扩散非常缓慢，但它们也吸引其他分子。结果是溶质分子在这样的基质中扩散的速率发生了变化，其变化量取决于吸引力的强弱。通过调整矩阵的属性，我们应该能够优化不同物种的NMR信号的分离，甚至解析不能通过正常DOSY实验分离的异构体的光谱。最初DOSY主要由化学家使用，但现在它被应用于食品科学，法医学和环境科学等不同领域。使用不同的DOSY矩阵将使这些用户能够更好地控制混合物中不同物种的信号如何分离，从而开辟新的应用。

Nuclear magnetic resonance (NMR) spectroscopy is the single tool most widely used by chemists for determining the molecular structures of unknown compounds. It is a wonderfully versatile and sensitive tool, but it has one major drawback: it is poor at analysing mixtures, so it is mostly used on carefully purified single compounds. Because many of Nature's most challenging problems - and many of those posed by synthetic chemists and by industry - are presented to us as mixtures, a great deal of effort goes into separating mixtures into their individual components so that they can be identified. Diffusion-ordered spectroscopy (DOSY) tries to get around this limitation by separating the NMR signals of different molecules, so that the signals from different species can be distinguished. Over the last decade our research group and others have developed the technique and applied it with great success - but almost always to simple solutions. In this project, a postdoctoral research fellow will investigate separating the spectra of mixture components more effectively by adding substances such as surfactants (the active ingredients of soaps and detergents), gels and soluble polymers to solvents to make a solution (a matrix ) that changes the way that molecules diffuse. These substances diffuse very slowly, but they also attract other molecules. The result is that the rates at which solute molecules diffuse in such a matrix are changed, by an amount that depends on how strong the attraction is. By tuning the properties of the matrix we should be able to optimise the separation of the NMR signals of different species, even resolving the spectra of isomers that cannot be separated by normal DOSY experiments. Initially DOSY was used largely by chemists, but it is now being applied in fields as varied as food science, forensic medicine, and environmental science. Using different matrices for DOSY will give such users much greater control over how signals of different species in a mixture are separated, opening up new applications.