STERICALLY LOADED ZIRCONOCENE COMPLEXES - FIRST EXAMPLE FOR A SIGMA-BOUND FLUORENYL LIGAND

The reaction of Cp2ZrCl2 (Cp = eta(5)-C5H5) with one or two equivalent s of fluorenyl lithium (C13H9Li) results in the formation of the mono and disubstitution products Cp2Zr(eta(1)-C13H9)Cl and Cp2Zr(eta(1)-C13 H9)(2). The corresponding Cp' derivative (Cp' = eta(5)-C5H4Me) gives a nalogous products. Instead of fluorenyl lithium, 2,7-di(methyl) fluore nyl lithium can also be applied in the reaction. The eta(1) bonding mo de of the fluorenyl ligand in Cp2Zr(eta(1)-C13H9)Cl could be demonstra ted by an X-ray structure. The dynamic behaviour of the cyclopentadien yl ligands in the products is described by temperature-dependent H-1 N MR spectroscopy.