High-pressure spectroscopic studies of solid inorganic, organic and organometallic materials

固体无机、有机和有机金属材料的高压光谱研究

• 批准号: 3768-2008
• 负责人: Butler, Ian
• 金额: $ 3.35万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2012
• 资助国家: 加拿大
• 起止时间: 2012-01-01 至 2013-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=513147
• 关键词: pressure; spectroscopic; studies; solid; inorganic

The application of high external pressures on molecular solids using diamond-anvil cells (DACs) can lead to dramatic structural changes in the materials, e.g., phase transitions and changes in interatomic distances (bond lengths and bond angles), electronic distributions in molecular orbitals (e.g., pi-backbonding), hydrogen bonding interactions, and relative energies of molecular orbitals often leading to piezochromism - color changes induced by pressure - a phenomenon employed in some pressure sensors. By using commercially available DACs, pressures up to about 100 kbar (ca. 100,000 atm), i.e., approaching the geological realm, can readily be achieved in the laboratory and any structural changes occurring can be conveniently monitored by a wide variety of molecular spectroscopic techniques, e.g., infrared, Raman, UV-visible, luminescence, Mossbauer, etc., as the pressure is steadily increased. In the operation of a DAC, two gemstone quality diamonds (culets, ~0.6 mm) are squeezed together mechanically by means of a sensitive screw mechanism and the material under investigation is placed, using an optical microscope, into a very small hole (300-micron diameter) drilled in the centre of a thin (300 micron), stainless-steel gasket located between the two diamonds. The whole hand-sized device is then placed under the microscope objective of an infrared or Raman microprobe spectrometer. The chief aim of our high-pressure DAC research is to examine spectroscopically whether or not structural changes can be induced in a range of solid inorganic (e.g., clays and other minerals), organic (e.g., drug polymorphs) and organometallic materials upon the application and subsequent release of high external pressures. In some cases, the densification effect of pressure may lead to the synthesis of completely new materials. In others, important information about chemical bonding interactions can be extracted. The high-pressure work proposed on clay minerals, for example, may contribute in providing a clearer understanding of the chemistry occurring in the Earth's crust and mantle, and perhaps even what role clay minerals may play in triggering earthquakes.

使用金刚石砧室（DAC）对分子固体施加高的外部压力可以导致材料中的显著结构变化，例如，相变和原子间距离（键长和键角）的变化，分子轨道中的电子分布（例如，π-背键）、氢键相互作用和分子轨道的相对能量，常常导致压致变色-由压力引起的颜色变化-在一些压力传感器中采用的现象。通过使用商业上可获得的DAC，高达约100 kbar（约100 kbar）的压力可被调节。100，000 atm），即，接近地质领域，可以在实验室中容易地实现，并且可以通过各种各样的分子光谱技术方便地监测发生的任何结构变化，例如，红外、拉曼、紫外-可见光、发光、穆斯堡尔等，因为压力稳定地增加。在DAC的操作中，两颗宝石级钻石（底托，~0.6 mm）通过灵敏的螺旋机构机械挤压在一起，并使用光学显微镜将所研究的材料放置在位于两颗钻石之间的薄（300微米）不锈钢垫圈中心钻的非常小的孔（300微米直径）中。然后将整个手掌大小的装置置于红外或拉曼微探针光谱仪的显微镜物镜下。我们的高压DAC研究的主要目的是通过光谱检查是否可以在一系列固体无机物中诱导结构变化（例如，粘土和其它矿物），有机物（例如，药物多晶型物）和有机金属材料。在某些情况下，压力的致密化效应可能导致全新材料的合成。在其他情况下，可以提取有关化学键相互作用的重要信息。例如，对粘土矿物提出的高压工作可能有助于更清楚地了解地壳和地幔中发生的化学反应，甚至可能有助于更清楚地了解粘土矿物在触发地震中可能发挥的作用。