Taming Fluorine: Metal-Organic Frameworks for the Heterogeneous Delivery of Fluorinated Building Blocks

Cornell University, Ithaca NY

Investigators

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Abstract

Project Summary Despite decades of reaction development, medicinal chemists still frequently face synthetic barriers when preparing molecules with potential therapeutic value. For example, the substitution of C–H bonds for C–F bonds in a target molecule can improve its metabolic stability, membrane permeability, and biological activity, but this substitution is often impossible to realize in the laboratory. This obstacle arises because the fluorination of otherwise simple building blocks or reagents generally renders them gaseous, toxic, corrosive, or unstable. While this “reagent problem” is not limited to organofluorine chemistry, it has prevented significant advances in this area. Therefore, the overall objective of the proposed research is to “tame” the reactivity of fluorinated building blocks and enable their use for the construction of complex fluorinated molecules. Specifically, the proposed multidisciplinary program aims to employ insoluble porous materials, which commonly serve as “hosts” for “guest” molecules in materials science, to control the reactivity of fluorinating agents. The resulting heterogeneous species will function as “nanovessels” capable of controllably releasing the stored reagents or as “nanoreactors” that facilitate new transformations within their pores. The central hypothesis of this proposal is that metal–organic frameworks, a relatively new class of porous, crystalline materials constructed from organic “linkers” and inorganic “secondary building units,” are the ideal platform to achieve this objective due to their unparalleled structural tunability. This research aim is part of the PI’s broader research program to unlock the potential of metal–organic frameworks for applications in organic synthesis, medicine, and structural biology. The PI is also exploring the use of electricity as a low-cost tool to enable the synthesis of complex molecules This administrative supplement will support the purchase of a powder X-ray diffractometer (PXRD) to facilitate the characterization of MOFs prepared as part of the parent proposal. PXRD is the most important method for determining the atomic-scale structures of nano-crystalline materials but remains challenging to carry out at Cornell University. Typically, synchrotron X-ray sources must be used to collect data, which results in significant delays (>6 weeks) between sample preparation and data acquisition. This purchase would allow for the acquisition of PXRD data in minutes instead of weeks at Cornell University.