Preparation and properties of some bis(cyclopentadienyl)ytterbium(II) complexes and the X-ray crystal and molecular structures of [Yb(η-C5H4SiMe3)2(thf)2]

Abstract

Reduction of [{Yb(η-C₅H₄SiMe₃)₂Cl}₂] by Na–Hg in tetrahydrofuran (thf) yields the purple, diamagnetic, toluene-soluble Yb^II title complex, from which similarly highly reactive, but thermally stable, Yb^II complexes [Yb(η-C₅H₄SiMe₃)₂(tmeda)](tmeda = Me₂NCH₂CH₂NMe₂) and Yb(η-C₅H₄SiMe₃)₂ are obtained, or [{Yb(η-C₅H₄-SiMe₃)₂I}₂] from oxidation by I₂; X-ray analysis of the title compound to R= 0·077 shows a roughly tetrahedral disposition of valencies around Yb, with Yb–O_av= 2·41 Å and Yb–C(η)_av= 2·75 Å.