Organolanthanoids. VI Syntheses of Cyclopentadienyllanthanoids by Transmetallation Reactions Between Thallous Cyclopentadienides and Lanthanoid Elements

Cyclopentadienyllanthanoids (C₅H₅)₃M(thf) (M = Ce, Nd, Sm, Gd or Er; thf = tetrahydrofuran), (C₅H₅)₃M (M = Er or Yb), (MeC₅H₄)₃M (M = Nd, Sm or Gd), (C₅H₅)₂Yb, (C₅H₅)₂Yb(dme) (dme = 1, 2-dimethoxyethane), and (MeC₅H₄)₂Yb(thf), have been synthesized in satisfactory-to-good yield by reaction of the lanthanoid elements with the thallous cyclopentadienides (RC₅H₄)Tl (R = H or Me) in tetrahydrofuran or 1, 2-dimethoxyethane. The outcome of the reaction of ytterbium with thallous cyclopentadienide [(C₅H₅)nYb; n = 2 or 3] depends on the stoichiometry; it has been shown that (C₅H₅)₃Yb is reduced by ytterbium metal to (C₅H₅)₂Yb and that the divalent compound is oxidized to (C₅H₅)₃Yb by thallous cyclopentadienide. Addition of mercury metal aids initiation of transmetallation, but it is not essential for reaction to occur.