Protons safe handling

The radical cation of a reactant formed via electron-hole oxidation may also be subject to nucleophilic attack. For example, the radical cation of p-dimeth-oxybenzene is attacked by cyanide and leading the formation of cyanoanisole [Eq. (13)] [118]. Similarly, selective fluorination of triphenylmethane on irradiated TiOj in the presence of AgF has been reported [Eq (14)] [119]. A stable carbocation, which is formed after a sequential electron transfer and proton elimination from the reactant, is key for successful fluorination (Fig. 4). Phogocatalytic fluorination employs safe and easy-to-handle reagents and eliminates the need for toxic fluorine gas or other problematic fluorination reagents. 

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