Synthesis and polymerization properties of substituted ansa-Bis(fluroenylidene) complexes of zirconium

The steric and electronic influence of various substituents at different po sitions of the fluorenylidene fragment effects the catalytical properties o f the MAO activated bis(fluorenylidene) complexes [C13H8 - nRn-(CH2)(2)-C13 H8 - nRn]ZrCl2 (n = 0-2; R = H, alkyl, aryl, -(CH)(4)-, -OCH3). We report t he synthesis and characterization of 27 new ansa bis(fluorenylidene) zircon ium dichloride complexes and illustrate their application in the homogeneou sly catalyzed polymerization of ethylene. The obtained results are compared with those of known bis(fluorenyl)complexes.