Amtawong, Jaruwan; Skjelstad, Bastian Bjerkem; Handford, Rex C.; Suslick, Benjamin A.; Balcells, David; Tilley, T. Don published the artcile< C-H Activation by RuCo3O4 Oxo Cubanes: Effects of Oxyl Radical Character and Metal-Metal Cooperativity>, Electric Literature of 76-84-6, the main research area is carbon hydrogen bond activation ruthenium cobalt oxo cubane; oxyl radical preparation character metal cooperativity.
High-valent multimetallic-oxo/oxyl species have been implicated as intermediates in oxidative catalysis involving proton-coupled electron transfer (PCET) reactions, but the reactive nature of these oxo species has hindered the development of an in-depth understanding of their mechanisms and multimetallic character. The mechanism of C-H oxidation by previously reported RuCo3O4 cubane complexes bearing a terminal RuV-oxo ligand, with significant oxyl radical character, was investigated. The rate-determining step involves H atom abstraction (HAA) from an organic substrate to generate a Ru-OH species and a carbon-centered radical. Radical intermediates are subsequently trapped by another equivalent of the terminal oxo to afford isolable radical-trapped cubane complexes. D. functional theory (DFT) reveals a barrierless radical combination step that is more favorable than an oxygen-rebound mechanism by 12.3 kcal mol-1. This HAA reactivity to generate organic products is influenced by steric congestion and the C-H bond dissociation energy of the substrate. Tuning the electronic properties of the cubane (i.e., spin d. localized on terminal oxo, basicity, and redox potential) by varying the donor ability of ligands at the Co sites modulates C-H activations by the RuV-oxo fragment and enables construction of structure-activity relationships. These results reveal a mechanistic pathway for C-H activation by high-valent metal-oxo species with oxyl radical character and provide insights into cooperative effects of multimetallic centers in tuning PCET reactivity.
Journal of the American Chemical Society published new progress about C-H bond activation. 76-84-6 belongs to class alcohols-buliding-blocks, and the molecular formula is C19H16O, Electric Literature of 76-84-6.
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