SYNTHESIS AND STRUCTURE OF ORGANOLANTHANIDE COMPLEXES WITH THE 2-METHOXYETHYLCYCLOPENTADIENYL LIGAND

This review presents a brief account of our recent investigations on s ynthetic and structural organolanthanide complexes with the 2-methoxye thylcyclopentadienyl ligand. Lanthanide metals possess large ionic rad ii and strong Lewis acidity, and by using 2-methoxyethylcyclopentadien yl as ligand, the oxygen atom in the ligand can coordinate to the lant hanide metal center in addition to the cyclopentadienyl system. Some n ovel organolanthanide complexes with such as an intramolecular coordin ation bond were successfully synthesized and structurally characterize d. The formation of a chelating five-membered ring structure via the i ntramolecular coordination bond results in an increase in the steric e ffect and coordination number of the lanthanide metals. The coordinati on need of light lanthanide metals is thus satisfied, and the synthese s and characterization of organometallic light lanthanide complexes ca n be achieved, especially for the complexes of lanthanum, such as (CH3 OCH2CH2C5H4)(3)La, [(CH3OCH2CH2C5H4)(2)La(mu-Cl)](2), (CH3OCH2CH2C5H4) (2)LaI, [(CH3OCH2CH2C5H4)(2)La(mu-H)](2) and (CH3OCH2CH2C5H4)(2)LaBH4. Moreover, the structures of organolanthanide complexes with this liga nd depend not only on the size of the lanthanide cations, but also on the size of the anions.