High valent RuV–oxo intermediates are commonly invoked in substrate bond activation steps involving O–O bond formation or H-atom abstraction, but investigations into their electronic and chemical properties have been rather limited due to their reactive nature and rarity. The incorporation of Ru into a [Co3O4] cluster via a single-step assembly reaction yielded an unprecedented Ru(O)Co3(μ3-O)4(OAc)4(py)3 cubane featuring an isolable, yet reactive RuV–oxo moiety. EPR, ENDOR, and DFT studies support a valence-localized [RuV(S=½)CoIII3(S=0)O4] configuration and a small degree of covalency in the cubane core. Natural bond orbital (NBO) calculations reveal cooperative orbital interactions of the Co3O4 framework in supporting the Ru–O moiety. Significant oxyl radical character in the RuV–O unit is experimentally demonstrated by radical coupling reactions between the oxo cubane and both 2,4,6-tri-tert-butylphenoxyl and trityl radicals. The oxo cubane oxidizes organic substrates and, notably, reacts with water to form an isolable μ-oxo bis-cubane complex [(py)3(OAc)4Co3(μ3-O)4RuIV]–O–[RuIVCo3(μ3-O)4(OAc)4(py)3].

Ruthenium–cobalt oxo cubane bearing a terminal RuV–oxo

2019 Fall National Meeting

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