Carbon–fluorine and –hydrogen bond activation and carbon–carbon bond formation in η⁵-pentamethylcyclopentadienyl-rhodium and -iridium phosphine complexes; crystal structures of [M(η⁵-C₅Me₅)Cl{(C₆F₅)₂PCH₂CH₂P(C₆F₅)₂}]⁺BF₄^–(M = Rh or Ir)

Abstract

The reaction between [{M(η5-C5Me5)Cl(µ-Cl)}2](M = Rh or Ir) and (C6F5)2PCH2CH2P(C6F5)2(dfppe) in refluxing benzene yielded the cationic species [M{η5-C5Me3[CH2C6F4P(C6F5)CH2]2-1,3}Cl]+ in which two C–F and two C–H bonds have been cleaved and two C–C bonds formed; HF is also produced. The complexes [M(η5-C5Me5)Cl(dfppe)]+BF4–(M = Rh or Ir), which have not undergone C–F bond activation, were formed by treatment of [{M(η5-C5Me5)Cl(µ-Cl)}2] with NH4BF4 and dfppe, and have been structurally characterized by X-ray crystallography. Activation of the C–F bonds in these complexes is induced by thermolysis in refluxing ethanol. The reaction between [{M(η5-C5Me5)Cl(µ-Cl)}2](M = Rh or Ir) and dfppe in refluxing ethanol yielded a mixture of the cations [M(η5-C5Me5)Cl(dfppe)]+, [M{η5-C5Me3[CH2C6F4P(C6F5)CH2]2-1,3}Cl]+ and, where M = Rh, the singly C–F bond-activated species [Rh{η5-C5Me4CH2C6F4P(C6F5)CH2CH2P(C6F5)2}Cl]+.