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Substituent effects on titanocenium catalysts
Author(s) -
Kucht Andreas,
Kucht Homa,
Song Wei,
Rausch Marvin D.,
Chien James C. W.
Publication year - 1994
Publication title -
applied organometallic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 71
eISSN - 1099-0739
pISSN - 0268-2605
DOI - 10.1002/aoc.590080503
Subject(s) - methylaluminoxane , chemistry , catalysis , substituent , ethylene , trifluoromethyl , olefin fiber , polymer chemistry , metallocene , medicinal chemistry , boron , ziegler–natta catalyst , ion , organic chemistry , polymerization , polymer , alkyl
Titanocene dichloride (1) and its bis(trifluoromethyl) (2) and bis( N,N ‐dimethylamino) (3) derivatives have been compared as catalysts for ethylene and propylene polymerizations using both methylaluminoxane (MAO) and triphenylcarbenium tetrakis(pentafluorophenyl)borate (4)/triisobutylaluminum (TIBA) as cocatalysts. The differences between the activities of the three ‘free’ titanocenium ions and the M w of the polyolefins produced by them may be attributable to the relative stabilities of the intermediate olefin–titanocenium π‐complexes. Interaction of either the neutral MAO or its anion with the titanocenium species may be responsible for the significantly lower catalytic efficiencies when the precursors were activated by MAO than by the 4/TIBA system.