NSF Award
1506266
With this award, the Macromolecular, Supramolecular and Nanochemistry Program in the Chemistry Division is funding Professor Julius Rebek of the Scripps Research Institute to study supramolecular "chaperones" for organic reactions in water. Currently the majority of chemical reactions performed in industry take place in organic solvents, solvents that are generally obtained from petrochemicals. This proposal intends to research how those reactions could be performed in water. The research involves the use of new synthetic compounds that act as containers for smaller molecules. While molecules are inside the containers, they adopt new shapes that increase their probability for known reactions and make possible reactions that are unknown outside the containers in water. The basic research proposed is targeted at scientific training and discovery; the applied research proposed is aimed at inventions that move chemical reactions from the limitations of petrochemicals into the most ecofriendly and least expensive solvent, water.<br/><br/>This proposal intends to apply synthetic, water-soluble container hosts "cavitands" to alter the behavior of small molecules held inside. Cavitands bind their target guests, temporarily isolate them from the aqueous medium, place them a hydrophobic environment and fold them into reactive shapes. The cavitands operate over a range of pH and take up hydrocarbon chains in conformations that bury the hydrophobic parts of the guests and bring their ends close together. The unusual shape of the guest molecules will be harnessed to guide reactions along pathways that are improbable, or even unknown in bulk solution. The U-shaped arrangements can promote a number of macrocyclic processes and remote functionalization reactions. Tactics to force turnover and promote catalysis with the cavitands in water will be tested. The applications are departures from existing methods involving template effects and atom transfer reactions that are typically performed in organic media.
