Related Experiment Video
Updated: Jul 3, 2026

Synthesis of Hypervalent Iodonium Alkynyl Triflates for the Application of Generating Cyanocarbenes
Published on: September 8, 2013
Photocatalytic Controlled Halodefluorination of Perfluoroalkyl Compounds Using N-Arylphenothiazines
Michael G J Doyle1, Maria Elgaard Jespersen1, Shana Noureen1
1Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford OX1 3TA, United Kingdom.
Abstract:
Recent advances in C-F bond activation of per- and polyfluoroalkyl substances (PFAS) have enabled complete degradation of fluorochemical waste, yet achieving precise, site-selective monodefluorination continues to present a significant synthetic challenge. Here, we demonstrate that N-arylphenothiazine photocatalysts enable controlled halodefluorination of perfluoroalkyl compounds using simple halide salts. Mechanistic studies support a consecutive photoinduced electron transfer (conPET) manifold, where the photocatalyst operates as a potent excited-state reductant and oxidant in succession under single- or multiwavelength irradiation. Single-electron halide oxidation is mediated by a transient radical cation superoxidant *[PC]•+, which facilitates net halogen metathesis with high fidelity. This study further exemplifies the redox versatility of N-arylphenothiazine photosensitizers and contributes to the development of mechanistically diverse methods for functionalization of strong C-F bonds in polyfluorinated molecules.
More Related Videos
Related Concept Videos
Electrophilic Aromatic Substitution: Fluorination and Iodination of Benzene
Nucleophilic Aromatic Substitution of Aryldiazonium Salts: Aromatic SN1
In the Sandmeyer reaction, for example, the diazonio group is replaced by a chloro, bromo, or cyano...
Radical Substitution: Hydrogenolysis of Alkyl Halides with Tributyltin Hydride
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation reactions,...
ortho–para-Directing Deactivators: Halogens
Diazonium Group Substitution with Halogens and Cyanide: Sandmeyer and Schiemann Reactions
Alkyl Halides
Alkyl halides are halogen-substituted alkanes wherein one or more hydrogen atoms of an alkane is replaced by a halogen atom such as fluorine, chlorine, bromine, or iodine. The carbon atom in an alkyl halide is bonded to the halogen atom, which is sp3-hybridized and exhibits a tetrahedral shape.
Unlike alkyl halides, compounds in which a halogen atom is bonded to an sp2 -hybridized carbon atom of a carbon-carbon double bond (C=C) are called vinyl halides. Whereas aryl...

