Action-at-a-Distance via Ice-Like point Defects: Relating Catalytic Gas-Hydrate Formation and Antifreeze Protein Action to Epitaxial Growth of Gas Hydrates

俄克拉荷马州立大学的Paul Devlin在化学系化学结构、动力学和机制项目的支持下，了解和修改含有捕获气体分子的晶体水合物的基本物理和化学性质。这些天然气水合物是由水分子组成的冰状晶格，其中包含了小笼子，作为其他物种的分子大小的陷阱。天然气水合物储量丰富，具有重要的技术作用。人们对它们的发生和物理性质了解甚多；但较少涉及它们在形成过程中参与的氢键化学和催化过程。对这些过程的更好理解可能会对在鱼类和其他物种中观察到的吸附抗冻蛋白（AFP）抑制冰的形成产生影响。该项目为一些本科生提供了研究机会，并涉及与来自土耳其的研究人员合作。本研究包括实验研究和理论研究。晶格缺陷在冰中很常见，并且很容易由氢键客体大量生成，通过诱导固态分子迁移率促进快速水合物形成。加入适当的客体催化剂（例如，醚四氢呋喃（THF）），液滴立即结晶为气体水合物颗粒。在天然气水合物中，这种微米距离缺陷的催化作用是更普遍的兴趣。在这个项目中，Devlin教授和他的本科生研究助理正在使用傅里叶变换红外（FTIR）光谱来探索冰状点缺陷的行为，这些缺陷是影响笼形水合物（CH）形成的分子行为的基础，以及防冻蛋白的功能。通过实验研究的CH系统的从头算和分子动力学（MD）计算也获得了新的见解。这项计算工作是与土耳其卡拉布鲁克大学的Nevin Uras-Aytemiz教授合作完成的。

Paul Devlin of Oklahoma State University is supported by the Chemical Structure, Dynamics and Mechanisms Program of the Chemistry Division to understand and modify the basic physical and chemical properties of crystalline hydrates that contain trapped gas molecules. These gas hydrates are ice-like lattices of water molecules with incorporated small cages that serve as molecule-size traps for other species. Gas hydrates are abundant in nature and have significant technological roles. Much is known about their occurrence and physical properties; but less about their participation in hydrogen-bond chemistry and catalytic processes during their formation. A better understanding of these processes may have implications with respect to the suppression of ice formation by adsorbed antifreeze-proteins (AFP) as observed in fish and other species. This project provides research opportunities for a number of undergraduate students, and involves collaboration with a researcher from Turkey. This research includes both experimental and theoretical studies. Lattice defects, common in ice and readily generated in much greater abundance by hydrogen-bonding guests, facilitate rapid hydrate formation by inducing solid-state molecular mobility. With a proper guest catalyst included (for example, the ether tetrahydrofuran (THF)), droplets instantly crystallize as gas-hydrate particles. This catalytic action of defects at micron distances within gas hydrates is of more general interest. In this project, Prof. Devlin and his undergraduate research assistants are using Fourier Transform Infrared (FTIR) spectroscopy to explore how the behavior of ice-like point defects that underlie molecular actions that may influence the formation of clathrate hydrates (CH), as well as the function of antifreeze proteins. Insights are also being gained through ab initio and molecular dynamics (MD) calculations on the CH systems being studied experimentally. The computational work is being done in collaboration with Professor Nevin Uras-Aytemiz, of Karabuk University, Turkey.