Organolanthanide and organoactinide oxidative additions exhibiting enhanced reactivity. 4. Products, stoichiometry, and preliminary kinetic studies of the reaction of (C5Me5)2SmII·OEt2 and (C5Me5)2EuII·OEt2 with alkyl and aryl halides. Evidence ...

Article abstract of DOI:10.1021/om00149a039

Full title: Organolanthanide and organoactinide oxidative additions exhibiting enhanced reactivity. 4. Products, stoichiometry, and preliminary kinetic studies of the reaction of (C₅Me₅)₂Sm^II·OEt₂ and (C₅Me₅)₂Eu^II·OEt₂ with alkyl and aryl halides. Evidence for the importance of electron transfer in atom-abstraction oxidative additions. (C₅Me₅)₂Sm^II·OEt ₂ exhibits oxidative addition reactions with alkyl and aryl halides faster than any f-block organometallic compound studied to date. The generalized stoichiometry displayed is (a + b)(C₅Me₅)₂Sm^II·OEt ₂ + (a + c)RX → (a - 2c)(C₅Me₅)₂Sm^IIIX + (b)(C₅Me₅)₂Sm^IIIR + (c)/z-[(C₅Me₅)₃Sm₂ ^IIIX₃]_z + (c)C₅Me₅R + (a + b)Et₂O + (a - b)R? products. On the other hand, (C₅Me₅)₂Eu^II·OEt₂ undergoes a nonredox reaction with alkyl and aryl halides, acting only as a Eu^II-Grignard reagent according to the stoichiometry: 1.0(C₅Me₅)₂Eu^II·OEt ₂ + 2.0RX → 1.0EuX₂ + 2.0C₅Me₅R. Comparisons of the relative rates of reaction between (C₅Me₅)₂Sm^II·OEt₂, (C₅Me₅)₂Eu^II·OEt₂, (C₅Me₅)₂Yb^II·OEt₂, and (C₅Me₅)₂U^III(Cl)(THF) reveals the series Sm ? U > Yb ? Eu and supports the proposal that the transition state for these inner-sphere atom-abstraction oxidative addition reactions contains the anticipated contribution from electron transfer.