78402-19-4Relevant articles and documents
Low-coordinate cobalt fluoride complexes: Synthesis, reactions, and production from C-F activation reactions
Dugan, Thomas R.,Goldberg, Jonathan M.,Brennessel, William W.,Holland, Patrick L.
, p. 1349 - 1360 (2012/04/10)
A cobalt(II) fluoride complex, [LtBuCo(μ-F)]2 [LtBu = 2,2,6,6-tetramethyl-3,5-bis(2,6-diisopropylphenylimido)hept- 4-yl], was synthesized from LtBuCo using Me3SnF via homolytic cleavage of the Sn-F bond. LtBuCo also performed the overall binuclear oxidative addition of fluorinated arenes to give [L tBuCo(μ-F)]2 and a cobalt(II) aryl complex of the corresponding fluorobenzene substrate in a 1:2 molar ratio. The C-F activation reaction has a first-order rate dependence on both cobalt and fluorobenzene concentrations. The rate is increased by meta-fluoride substituents, and slowed by ortho-fluoride substituents, suggesting electronic and steric influences on the transition state, respectively. The data are most consistent with a mechanism beginning with rate-limiting oxidative addition of the aryl fluoride to cobalt(I), followed by rapid reduction of the cobalt(III) aryl fluoride intermediate by a second molecule of LtBuCo. [LtBuCo(μ- F)]2 also reacts with Et3SiH to give the hydride complex [LtBuCo(μ-H)]2. This hydride complex has low reactivity toward alkenes and N2, in contrast to an earlier report.
