Carbon-fluorine bond cleavage by zirconium metal hydride complexes
- Univ. of Rochester, NY (United States). Dept. of Chemistry
The use of transition metal complexes to cleave strong carbon-fluorine bonds has blossomed in the past several years. Many late transition metal complexes with electron-donating ligands are believed to undergo oxidative addition to the C-F bond of a fluorinated aromatic group. The zirconium hydride dimer [Cp{sub 2}ZrH{sub 2}]{sub 2} reacts with C{sub 6}F{sub 6} at ambient temperature to give Cp{sub 2}Zr(C{sub 6}F{sub 5})F as the major product along with Cp{sub 2}ZrF{sub 2}, C{sub 6}F{sub 5}H and H{sub 2}. Neither the reaction rate nor the product ratio is affected by changes in H{sub 2} pressure or the concentration of C{sub 6}F{sub 6}. The reaction follows zero-order kinetics. The new compound Cp{sub 2}Zr(C{sub 6}F{sub 5})F has been structurally characterized. [Cp{sub 2}ZrH{sub 2}]{sub 2} reacts with C{sub 6}F{sub 5}H to give Cp{sub 2}Zr(p-C{sub 6}F{sub 4}H)F, Cp{sub 2}ZrF{sub 2}, C{sub 6}F{sub 4}H{sub 2}, and H{sub 2}. The zirconium hydride Cp{sub 3}ZrH has been structurally characterized and also reacts with C{sub 6}F{sub 6}. The products of the reaction are CpH, Cp{sub 2}Zr(C{sub 6}F{sub 5})F, C{sub 6}F{sub 5}H, Cp{sub 2}ZrF{sub 2}, Cp{sub 4}Zr, and Cp{sub 3}ZrF. The reaction rate is first order in [Cp{sub 3}ZrH] and [C{sub 6}F{sub 6}], but the product ratio is unaffected by the concentration of C{sub 6}F{sub 6}. Possible mechanisms of these reactions are discussed.
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG02-86ER13569
- OSTI ID:
- 682123
- Journal Information:
- Organometallics, Vol. 18, Issue 16; Other Information: PBD: 2 Aug 1999
- Country of Publication:
- United States
- Language:
- English
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