Organolanthanoids.X. Syntheses of Cyclopentadienyllanthanoids by Transmetalation Reactions in Pyridine, Acetonitrile and Ethers

Abstract

The complexes, (C₅H₅)₃M( py ) (M = Nd, Sm, Eu or Yb ), (C₅H₅)₂Eu( py ), and (C₅H₅)₂Yb( py )₂ have been prepared from the appropriate lanthanoid elements and thallous cyclopentadienide in pyridine, and (C₅H₅)₃M( NCMe ) (M = Nd , Sm or Yb ) and (C₅H₅)₂Yb( NCMe ) from similar reactions in acetonitrile. Ligand exchange or addition has also been used to give (C₅H₅)₃Sm( py ), (C₅H₅)₂Yb( py )₂ and (C₅H₅)₂Yb( NCMe ). Ytterbium metal reduces (C₅H₅)₃Yb( py ) in pyridine to (C₅H₅)₂Yb( py )₂, which is oxidized back to (C₅H₅)₃Yb( py ) by TI(C₅H₅). Europium with (C₅H₅)₂Hg in tetrahydrofuran yields (C₅H₅)₃Eu( thf ), and (C₅H₅)₂Eu is not isolated by using an excess of metal. Oxidation of (C₅H₅)₂Eu to (C₅H₅)₃Eu is effected by (C₅H₅)₂Hg in tetrahydrofuran but not by T1(C₅H₅) in 1,2-dimethoxyethane. Europium and ytterbium react with bis(pentafluoropheny1)mercury and cyclopentadiene in pyridine to give (C₅H₅)₃M( py ) (M = Eu or Yb ).