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保罗·德夫林得到化学部化学结构、动力学和机制计划的支持，以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。这些气体水合物是冰一样的水分子晶格，带有结合的小笼子，为其他物种提供分子大小的陷阱。天然气水合物在自然界中含量丰富，具有重要的技术作用。人们对它们的存在和物理性质知之甚少，但对它们在形成过程中参与氢键化学和催化过程知之甚少。更好地了解这些过程可能对鱼类和其他物种中观察到的吸附抗冻蛋白(AFP)抑制冰层形成具有重要意义。该项目为一些本科生提供了研究机会，并涉及与一名来自土耳其的研究人员的合作。本研究包括实验研究和理论研究。晶格缺陷在冰中很常见，很容易由氢键客体产生更丰富的晶格缺陷，通过诱导固态分子移动来促进快速水合物的形成。加入适当的客体催化剂(例如，乙醚四氢呋喃(THF))，液滴立即结晶为气体水合物颗粒。天然气水合物中微米距离的缺陷的这种催化作用更具普遍意义。在这个项目中，Devlin教授和他的本科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如何影响笼状水合物(CH)的形成以及抗冻蛋白的功能。通过从头算和分子动力学(MD)对正在实验研究的CH系统进行计算，也获得了一些见解。计算工作是与土耳其卡拉巴克大学的内文·乌拉斯-艾特米兹教授合作完成的。

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.