Photooxidation of fluoride for C-F and S-F bond formation

Abstract

The importance of organofluorides has been growing especially due to their commercial applications. The applications of these organofluorides include the agrochemical industry, materials science, and medicinal chemistry, with the use of radiotracers labeled with fluorine-18 for cancer detection via positron emission tomography. However, fluorination is known to be a very challenging process due to F2 high reactivity and toxicity. Herein, we aim to address this issue by developing a heterogeneous catalyst capable to oxidize fluoride, in order to activate this anion to promote fluorination reactions. Recently, a new simple and successful method for the synthesis of poly(heptazine imides) (PHI) and poly(triazine imides) (PTI) opened the doors for their application in photocatalysis, with the use of K-PHI as photocatalyst in chlorination and bromination of electron-rich aromatic compounds. Therefore, the aim of this study is to investigate the use of PHI-based materials to promote the fluorination of organic compounds using KF as an inexpensive and safe fluorine source. The design of the electronic properties of the PHI-based materials, in order to reach the oxidation potential needed to oxidize fluoride ions (i. e. 2.9 V), will be carried through a cation exchange method and partial protonation of the resulting material. We hypothesize that after the modification of the PHI-based material, they will be suitable to promote the fluorination of organic compounds via photocatalysis, once their valance band position will be higher than 2.9 V.(AU)