Organolanthanoids. XV. The Preparation of Carboxylatobis(cyclopentadienyl)ytterbium(III) Complexes by Oxidation of Bis(cyclopentadienyl)ytterbium(II)

Abstract

The complexes, Cp₂Yb(O₂CR) [Cp = cyclopentadienyl; R = Me, CF₃, Ph, C₆F₅, C₆Br₅, o- MeO₂CC₆F₄ (tmcp), 2,4,6-Me₃C₆H₂ (tmp), pyridin-2-yl (pyr), or quinolin-2-yl (quin)] have been prepared in good yield by oxidation of bis(cyclopentadienyl)(1,2-dimethoxyethane)ytterbium(II) with the appropriate mercury(ll) or thallium(I) carboxylate, generally in tetrahydrofuran. Structural data suggest that four complexes (R=Me, CF₃, Ph or C₆F₅) are dimeric with bridging bidentate carboxylate groups, three (R = tmp, pyr or quin) are monomeric with chelating carboxylates, but the structure is less clear for R = C₆Br₅ or tmcp. Unit cell dimensions have been determined for bis(cyclopentadienyl)(2,4,6-trimethyibenzoato)ytterbium(III), but the structure could not be solved owing to decomposition of single crystals in the X-ray beam.