Polymerization with metallocene catalysts. Hydrooligomerization and NMR investigations concerning the microstructure of poly(cyclopentenes)

Hydrooligomerizations and polymerizations of cyclopentene were carried out using CS, C2 and C2v symmetric zirconocenes and methylaluminoxane as catalyst. The structure of the hydrotrimers was investigated by one- and twodimensional NMR spectroscopy and correlated to the structure of the polymers. The assignments for the 13C-NMR spectrum of the cis-1,3-enchained hydrotrimer made by Collins [3] are corrected. Cis-1,3-enchainment of the configurational base units in the poly(cyclopentenes) is confirmed. rac-[Me2Si(Ind)2]ZrCl2/MAO catalysis features crystalline polymers and the erythrodiisotactic hydrotetramer indicating highly stereoselective insertion. Cp2ZrCl2/MAO and [Ph2C(Fluo)(Cp)]ZrCl2/MAO show none or low stereoselectivity respectively yielding amorphous polymers and both of the diastereomeric hydrotetramers.