TETRAMETHYL(2-METHOXYETHYL)CYCLOPENTADIENYL COMPLEXES OF ZIRCONIUM(IV) - CRYSTAL-STRUCTURE OF [ETA(5) ETA-C-1-(5)(CH3)(4)(CH2CH2OCH3)]ZRCL3/

Several novel zirconium(IV) complexes with the chelating oxygen-contai ning cyclopentadienyl ligand, tetramethyl(2-methoxyethyl)cyclopentadie ne, have been synthesized. 2-methoxyethyl)cyclopentadienyl]trichlorozi rconium (2), (2-methoxyethyl)cyclopentadienyl]dichlorozirconium (3), ( 2-methoxyethyl)cyclopentadienyl]dichlorozirconium (4), and 5)-tetramet hyl(2-methylthioethyl)cyclopentadienyl] 2-methoxyethyl)-cyclopentadien yl]dichlorozirconium (5) have been prepared from the corresponding lit hium cyclopentadienide (1). The crystal structure of cyclopentadienyl complex 2 has been established by X-ray analysis. The coordination O-- >Zr bond in compound 2 exists both in the crystalline state and in sol utions. No coordination of this type was observed in complexes 3-5. Sy nthesized complexes 2-5 are discussed in comparison with their sulfur- containing analogs.