Reactions of Folded Molecules in Water

在化学工业中发生的大多数过程使用有机溶剂，通常从石化产品中获得的溶剂。使这些过程适应“最环保”的溶剂——水——仍然是一个挑战。这个项目将由斯克里普斯研究所的朱利叶斯·雷贝克教授进行，他使用容器形状的合成分子在水中进行反应。“容器”就像纳米容器一样，表现出强大的稳定性，可以在广泛的条件下使用和重复使用。这项研究的一个更广泛的影响是发展可持续化学的好处。另一个影响是发现了用于防水涂层和纳米机器的新分子。博士后研究人员从学习如何将研究项目从化学发现转化为新材料的应用中受益。被限制在小容器中的分子的化学性质——被称为空腔体的纳米级化合物——是一项相对较新的任务。这项研究利用了一项早期发现，即长链有机化合物在空腔空间内呈现出不寻常的折叠形状。由疏水力引起的折叠形状将衬底的两端推在一起并促进大环环化过程。空腔充当模板。折叠还会阻断链上的某些位点，并使其他位点暴露于与水介质中的试剂发生反应。阻断作用为功能化反应中的远程碳氢活化提供了新的化学途径，通常会导致5或6元环的大小。在扩展分子中相距遥远的官能团在空腔中折叠时被拉近。这些功能不再独立作用，可以相互影响反应性；显示这种“纠缠”的后果是本研究预期的基础科学创新之一。实际结果可能包括用于获取不能通过常规方法制造的分子的合成方法。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The majority of processes that take place in the chemical industry use organic solvents, solvents that are generally obtained from petrochemicals. Adapting these processes to the "greenest" solvent - water - remains a challenge. This project to be conducted by Professor Julius Rebek at The Scripps Research Institute uses synthetic, container-shape, molecules for reactions in water. The "containers" act as nanovessels that show robust stability and can be used and re-used over a wide range of conditions. A broader impact of this research is the benefit of developing sustainable chemistry. Another impact is the discovery of new molecules for use in water-proof coatings and nanomachines. Postdoctoral researchers benefit from learning how research projects translate from chemical discovery to applications in new materials.The chemistry of molecules confined to small containers - nanoscale compounds known as cavitands - is a relatively new undertaking. This research takes advantage of an early discovery that long-chain organic compounds assume unusual, folded shapes within the cavitand's space. The folded shapes, induced by hydrophobic forces, push the substrate's ends together and promote large-ring cyclization processes. The cavitands act as templates. Folding also blocks some sites on the chain and exposes others to reactions with agents in the aqueous medium. The blocking action promises new chemical pathways for remote carbon-hydrogen activation in functionalization reactions that typically lead to 5 or 6-membered ring sizes. Functional groups that are remote in extended molecules are brought into proximity when folded in cavitands. The functions no longer act independently and can affect each other's reactivity; showing the consequences of this "entanglement" is one of the basic science novelties expected from this research. The practical consequences may include synthetic methods for access to molecules that cannot be made by conventional means.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.