Characterization of a Ferryl Flip in Electronically Tuned Nonheme Complexes. Consequences in Hydrogen Atom Transfer Reactivity. Issue 2 (2nd December 2022)

• Record Type: Journal Article
• Authors: Dantignana, Valeria; Pérez‐Segura, M. Carmen; Besalú‐Sala, Pau; Delgado‐Pinar, Estefanía; Martínez‐Camarena, Álvaro; Serrano‐Plana, Joan; Álvarez‐Núñez, Andrea; Castillo, Carmen E.; García‐España, Enrique; Luis, Josep M.; Basallote, Manuel G.; Costas, Miquel; Company, Anna
• Is Part Of: Angewandte Chemie international edition. Volume 62:Issue 2(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-12-02
• Subjects: Atom Transfer -- Iron -- Isomerization -- Oxidation -- Oxoiron; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.202211361
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Two oxoiron(IV) isomers ( R 2a and R 2b ) of general formula [Fe IV (O)( R PyNMe3 )(CH3 CN)] 2+ are obtained by reaction of their iron(II) precursor with NBu4 IO4 . The two isomers differ in the position of the oxo ligand, cis and trans to the pyridine donor. The mechanism of isomerization between R 2a and R 2b has been determined by kinetic and computational analyses uncovering an unprecedented path for interconversion of geometrical oxoiron(IV) isomers. The activity of the two oxoiron(IV) isomers in hydrogen atom transfer (HAT) reactions shows that R 2a reacts one order of magnitude faster than R 2b, which is explained by a repulsive noncovalent interaction between the ligand and the substrate in R 2b . Interestingly, the electronic properties of the R substituent in the ligand pyridine ring do not have a significant effect on reaction rates. Overall, the intrinsic structural aspects of each isomer define their relative HAT reactivity, overcoming changes in electronic properties of the ligand. Abstract : The isomerization of pairs of electronically tuned oxoiron(IV) geometrical isomers is described, as a model for the "ferryl flip" observed in non‐heme enzymes. The position of the oxo ligand in the coordination sphere of the iron center has a strong impact on the hydrogen‐atom transfer (HAT) activity of the oxoiron(IV) compounds, while electronic effects do not play a significant role in HAT reactions.