STUDIES ON ORGANOLANTHANIDE COMPLEXES .61. SYNTHESIS AND CHARACTERIZATION OF 3-OXA-PENTAMETHYLENE BRIDGED ANSA-METALLOCENE CHLORIDES OF RARE-EARTH ELEMENTS

Several complexes [O(CH(2)CH(2)C(5)H(3)R)(2)LnCl] (R = (t)Bu, Ln = Y, Nd, Sm, Yb; R = SiMe(3), Ln = La, Y, Nd, Yb) were synthesized using ch elating ligands and characterized by mass-, IR-, H-1 NMR-spectroscopie s and elemental analyses. The spectra indicate that these complexes ar e unsolvated ansa-metallocene chlorides and the two bridged cyclopenta diene rings coordinate to the same metal ion with an intramolecular co ordination bond between the oxygen atom of the bridge and the metal io n. These complexes are still sensitive to air and moisture, but they a ll have good thermal stability under inert gas and excellent solubilit y in hydrocarbon solvents. The reactivities of the systems of these me tallocene chlorides and sodium hydride were investigated. Compared wit h the solubility of these complexes in a range of solvents, the influe nces of steric factors arising from the bulky substituents on the cycl opentadiene rings or the radial size of the metal ions are relatively slight.