STABLE IS(ETA(5)-TETRAHYDROINDENYL)]-ZIRCONACYCLOPENTANES - SYNTHESES, X-RAY CRYSTAL-STRUCTURES, STABILITY, AND CATALYSIS OF ETHYLENE POLYMERIZATION

The reaction of rac-(ebthi)Zr(eta(2)-Me3SiC2SiMe3) (1) [ebthi = 1,2-et hylene-1,1'-bis(eta(5)-tetrahydroindenyl)] with an excess of ethylene at room temperature leads to the corresponding zirconacyclopentane 3, which was isolated as stable yellow crystals and characterized by an X -ray crystal structure analysis. At 203 K complex 1 reacts with only 1 equiv of ethylene to form the zirconacyclopentene 2, possibly an inte rmediate in the reaction from 1 to 3. Upon activation with tris(pentaf luorophenyl)borane under an ethylene atmosphere, complex 3 was shown t o be an effective catalyst for ethylene polymerization. The reaction o f 2 equiv of styrene with the alkyne complex 1 leads to the unsymmetri cally substituted zirconacyclopentane 6.