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Tuning the H‐Atom Transfer Reactivity of Iron(IV)‐Oxo Complexes as Probed by Infrared Photodissociation Spectroscopy
Author(s) -
Tripodi Guilherme L.,
Dekker Magda M. J.,
Roithová Jana,
Que Lawrence
Publication year - 2021
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.202016695
Subject(s) - reactivity (psychology) , chemistry , photodissociation , adduct , ligand (biochemistry) , infrared spectroscopy , amine gas treating , photochemistry , spectroscopy , reactive intermediate , medicinal chemistry , crystallography , stereochemistry , catalysis , organic chemistry , medicine , biochemistry , physics , alternative medicine , receptor , pathology , quantum mechanics
Reactivities of non‐heme iron(IV)‐oxo complexes are mostly controlled by the ligands. Complexes with tetradentate ligands such as [(TPA)FeO] 2+ (TPA=tris(2‐pyridylmethyl)amine) belong to the most reactive ones. Here, we show a fine‐tuning of the reactivity of [(TPA)FeO] 2+ by an additional ligand X (X=CH 3 CN, CF 3 SO 3 − , ArI, and ArIO; ArI=2‐( t BuSO 2 )C 6 H 4 I) attached in solution and reveal a thus far unknown role of the ArIO oxidant. The HAT reactivity of [(TPA)FeO(X)] +/2+ decreases in the order of X: ArIO > MeCN > ArI ≈ TfO − . Hence, ArIO is not just a mere oxidant of the iron(II) complex, but it can also increase the reactivity of the iron(IV)‐oxo complex as a labile ligand. The detected HAT reactivities of the [(TPA)FeO(X)] +/2+ complexes correlate with the Fe=O and FeO−H stretching vibrations of the reactants and the respective products as determined by infrared photodissociation spectroscopy. Hence, the most reactive [(TPA)FeO(ArIO)] 2+ adduct in the series has the weakest Fe=O bond and forms the strongest FeO−H bond in the HAT reaction.