Enhancement of C−H Oxidizing Ability in Co–O2 Complexes through an Isolated Heterobimetallic Oxo Intermediate. Issue 12 (14th February 2017)

• Record Type: Journal Article
• Authors: DeRosha, Daniel E.; Mercado, Brandon Q.; Lukat‐Rodgers, Gudrun; Rodgers, Kenton R.; Holland, Patrick L.
• Is Part Of: Angewandte Chemie international edition. Volume 56:Issue 12(2017)
• Page Start: 3211
• Page End: 3215
• Publication Date: 2017-02-14
• Subjects: cobalt -- heterobimetallic complexes -- iron -- oxygen activation; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201612010
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: The characterization of intermediates formed through the reaction of transition‐metal complexes with dioxygen (O2 ) is important for understanding oxidation in biological and synthetic processes. Here, the reaction of the diketiminate‐supported cobalt(I) complex L tBu Co with O2 gives a rare example of a side‐on dioxygen complex of cobalt. Structural, spectroscopic, and computational data are most consistent with its assignment as a cobalt(III)–peroxo complex. Treatment of L tBu Co(O2 ) with low‐valent Fe and Co diketiminate complexes affords isolable oxo species with M2 O2 "diamond" cores, including the first example of a crystallographically characterized heterobimetallic bis(μ‐oxo) complex of two transition metals. The bimetallic species are capable of cleaving C−H bonds in the supporting ligands, and kinetic studies show that the Fe/Co heterobimetallic species activates C−H bonds much more rapidly than the Co/Co homobimetallic analogue. Thus heterobimetallic oxo intermediates provide a promising route for enhancing the rates of oxidation reactions. Abstract : Odd couple : Treatment of a side‐on dioxygen complex of cobalt with a low‐valent cobalt or iron diketiminate complex affords a homobimetallic Co/Co or a heterobimetallic Fe/Co oxo complex, respectively. C−H activation in the Co/Fe complex is three orders of magnitude faster than in the homobimetallic analogue.