Is Water Structure Important?

水的结构以及它与溶解的溶质和疏水表面自组装和相互作用的方式仍然是非常热门的话题。《科学》杂志将对水的研究列为2004年十大突破之一。固态水合物的形成和结构仍然是制药业感兴趣的一个主要话题。由于水结构对氢原子位置的强烈依赖，水结构的解释问题变得复杂。使用X射线无法准确定位氢原子。要有意义地讨论水在固态中的结构及其与有机溶质物种的相互作用，无论是生物的还是其他的，都必须涉及使用中子衍射来定位H原子。这项工作还必须得到适当的计算和相应的系统数据库分析以及固体核磁共振光谱、TGA/DSC和振动光谱等辅助技术的支持。该项目将收集大量关于晶体内水分子和团簇的实验中子数据，并使用基于这些实验坐标的计算来确定相对氢键能。要回答的关键问题是，水对自身和周围环境有什么影响，水-水相互作用如何与水-溶质(或在固态下，水合物-宿主)相互作用竞争，特别是在存在许多水分子的‘大系统’中。我们将获得的见解将有助于理解物理性质，如溶解度、形成水合物的倾向以及有机化合物，特别是药物，采用一种以上固体形式的趋势。

The structure of water and in the way it self-assembles and interacts with dissolved solutes and with hydrophobic surfaces continues to be highly topical. Science ranked the study of water among the top 10 breakthroughs in 2004. The formation and structure of solid state hydrates continues to be a topic of major interest to the pharmaceuticals industry. The problem of interpretation of water structure is complicated by its strong dependence on hydrogen atom positions. Hydrogen atoms cannot be located accurately using X-rays. A meaningful discussion of water structure in the solid state and of its interaction with organic solute species, biological or otherwise, must involve location of H atoms using neutron diffraction. The work must also be backed up by appropriate calculations and corresponding systematic database analysis as well as supporting techniques such as solid state NMR spectroscopy, TGA/DSC and vibrational spectroscopy. This project will amass a body of experimental neutron data on water molecules and clusters within crystals and determine the relative hydrogen bonding energies using calculations based on these experimental coordinates. The key question to answer is what effect does water have on itself and its surroundings and how do water-water interactions compete with water-solute (or, in the solid state, hydrate-host) interactions, particularly in 'large systems' in which many water molecules are present. The insights we will gain will help understand physical properties such as solubility, tendency to form hydrates and the tendency of organic comounds, particularly pharmaceuticals, to adopt more than one solid form.