78402-19-4Relevant academic research and scientific papers
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.
MECHANISTIC STUDIES ON DECOMPOSITION OF TRIALKYLSTANNYLLITHIUMS
Kobayashi, Kazuko,Kawanisi, Mituyosi,Hitomi, Torazo,Kozima, Sinpei
, p. 299 - 311 (2007/10/02)
The fast decomposition of trialkylstannyllithiums, R3SnLi (R=Me, Et and Bu), in the presence of hexaalkyldistannanes, R3SnSnR3, was observed, and its mechanism was investigated kinetically.Partial dissociation of R3SnLi into a complex in a solvent cage is suggested to occur in the initial step.The RLi in the complex can be trapped instantaneously by R3SnSnR3 to afford R4Sn and R3SnLi, and the counterpart R2Sn: by R3SnLi giving R3SnR2SnLi.The decomposition of R3SnLi followed first-order kinetics within 3.5 h, corresponding well to the rate of disappearance of R3SnSnR3 and of appearance of R4Sn.The partial dissociation rate constant (k1) of Me3SnLi into the complex was determined as 2.0*10-3 min-1.The values of k1 are about 100 times those of rate constants (k') for decomposition of R3SnLi in the absence of R3SnSnR3.Reformation of R3SnLi from the complex is highly significant.
