A Terminal Iridium Oxo Complex with a Triplet Ground State. Issue 32 (3rd July 2019)

• Record Type: Journal Article
• Authors: Delony, Daniel; Kinauer, Markus; Diefenbach, Martin; Demeshko, Serhiy; Würtele, Christian; Holthausen, Max C.; Schneider, Sven
• Is Part Of: Angewandte Chemie international edition. Volume 58:Issue 32(2019)
• Page Start: 10971
• Page End: 10974
• Publication Date: 2019-07-03
• Subjects: hydrogen atom transfer -- iridium -- oxo complexes -- pincer complexes; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201905325
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: A terminal iridium oxo complex with an open‐shell ( S =1) ground state was isolated upon hydrogen atom transfer (HAT) from the respective iridium(II) hydroxide. Electronic structure examinations support large spin delocalization to the oxygen atom. Selected oxo transfer reactions indicate the ambiphilic reactivity of the iridium oxo moiety. Calorimetric and computational examinations of the HAT revealed a bond dissociation free energy for the IrO−H bond that is sufficient for hydrogen atom abstraction towards C−H bonds and small contributions from entropy and spin–orbit coupling to the HAT thermochemistry. Abstract : A terminal iridium(III) oxo complex was isolated and fully characterized. The ambiphilic oxo complex exhibits an unprecedented triplet ground state and large oxygen radical character. Thermochemical examination of the corresponding hydroxo/oxo (Ir II OH/Ir III O) hydrogen atom transfer couple indicates that the O−H bond dissociation (free) energy is sufficient for the activation of strong E−H bonds.