Mechanisms and consequences of chirally selective processes at mineral surfaces

生物学是手性的，也就是说，许多有机分子以化学上相同但镜像的形式存在。对‘左旋’形式的氨基酸和‘右旋’糖生物分子的强烈手性偏好是生物系统的一个决定性特征。对其他关键生物分子也显示出类似的偏好。这种手性的起源目前是人们非常感兴趣的主题，寻找选择左手分子而不是右手分子的非生物过程对生命起源和进化的地球化学模型具有深远的影响。水晶表面，例如构成固体地球的矿物表面，并不是手性盲的。一种对映体(“左手”或“右手”分子)在矿物表面的选择性吸附具有深远的意义；它被认为是自然界中观察到的同色性的可能原因之一。此外，手性选择性吸附也可能对有机物质(包括优先污染物)在环境中固定、运输和降解的机制产生重大影响。这项建议旨在记录在矿物表面可以发生的手性选择性的程度，并非常重要地阐明这种选择发生的机制。我们将进行一系列实验室实验，以量化不同矿物和不同矿物表面(不同晶体取向)的选择性吸附效果。这些实验将结合使用现代表面科学技术对有机分子和矿物表面之间的原子尺度相互作用进行详细研究，这将使我们能够更好地了解吸附和手性选择发生的机制。

Biology is chiral; that is to say that many organic molecules exist in chemically identical but mirror image forms. A strong chiral preference for 'left-handed' forms of amino acids and 'right-handed' sugar biomolecules is a defining characteristic of biological systems. Similar preferences are shown for other key biomolecules. The origins of this chirality are currently the subject of much interest and the search for abiotic processes that select 'left-handed' rather than 'right-handed' molecules has profound implications for geochemical models of life's origin and evolution. Crystalline surfaces, such as the surfaces of minerals that make up the solid Earth, are not 'chirally blind'. Selective adsorption of one enantiomer ('left' or 'right' handed molecules) on mineral surfaces has profound implications; it has been cited as one possible cause of the homochirality observed in nature. Furthermore chirally selective adsorption may also have major consequences for the mechanisms by which organic material (including priority pollutants) is fixed, transported and degraded in the environment. This proposal aims to document the degree of chiral selectivity that can occur at mineral surfaces and, very importantly, shed light on the mechanisms by which this selection occurs. We will conduct a series of laboratory experiments to quantify the selective adsorption effects of different minerals and different mineral surfaces (different crystallographic orientations). These experiments will be coupled to a detailed examination of the atomic- scale interactions between organic molecules and mineral surfaces, using modern techniques of surface science, that will enable us to understand better the mechanisms by which adsorption and chiral selection occur.