Polymerization of Cyclopentene Using Metallocene Catalysts: Polymer Tacticity and Properties

Hydro-oligomerization or polymerization of cyclopentene using racemic 1,2-ethylenebis(η 5 -indenyl)zirconium dichloride (1) and methylaluminoxane leads to the production of poly(cis-1,3-cyclopentane) in which individual monomer units are incorporated in an isotactic manner. This was ultimately demonstrated through independent synthesis of the single, stereoisomeric tetramer produced under hydro-oligomerization conditions. In contrast to these result, hydro-oligomerization of cyclopentene with racemic 1,2-ethylenebis-(η 5 -tetrahydroindenyl)zirconium dichloride (5) led to the production of oligomers in which cyclopentene is incorporated in a cis- and trans-1,3 manner