Reactions of Folded Molecules in Water

化学工业中发生的大多数过程使用有机溶剂，有机溶剂通常从石化产品中获得。使这些工艺适应“最环保”的溶剂--水--仍然是一项挑战。该项目由斯克里普斯研究所的朱利叶斯·里贝克教授主持，利用合成的容器形状的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，可以在各种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料和纳米机械的新分子。博士后研究人员受益于了解研究项目如何从化学发现转化为新材料的应用。限制在小容器中的分子化学-被称为空洞的纳米级化合物-是一项相对较新的工作。这项研究利用了一个早期的发现，即长链有机化合物在洞穴的空间内呈现不寻常的折叠形状。疏水力诱导的折叠形状将底物的末端推到一起，并促进大环环化过程。空洞充当模板。折叠还会阻止链上的一些位置，并使其他位置与水介质中的试剂发生反应。这种封闭作用有望为官能化反应中的远程碳氢活化提供新的化学途径，这些反应通常会导致5或6元环大小。当折叠在空穴中时，延伸分子中远离的官能团就会接近。这些功能不再独立发挥作用，可能会影响彼此的反应性；展示这种“纠缠”的后果是这项研究期待的基本科学新奇之一。实际结果可能包括传统方法无法获得的分子的合成方法。这一裁决反映了NSF的法定使命，并通过使用基金会的智力优势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.