An unprecedented alpha-olefin distribution arising from a homogeneous ethylene oligomerization catalyst.

Treatment of the bis(benzimidazolyl)amine chromium complex 2 with ethylene in the presence of MAO affords an exceptionally active oligomerization catalyst and an unprecedented distribution of 1-olefin products in which the C4n series is much more abundant than the C4n+2 series. Deuterium labeling studies are consistent with a metallacyclic chain growth mechanism in which the unusual product distribution arises from the interplay of two sites.

Combining hard and soft donors in early-transition-metal olefin polymerization catalysts.

Bis(phosphanylphenoxide) complexes of the group 4 metals, upon activation by methylaluminoxane, are highly active for ethylene and propylene polymerization; a zirconium derivative possesses one of the highest propylene polymerization activities found to date for a nonmetallocene system.

Experimental evidence for large ring metallacycle intermediates in polyethylene chain growth using homogeneous chromium catalysts.

Deuterio-ethylene labeling studies on two homogeneous chromium ethylene oligomerization catalysts show that chain propagation proceeds via metallacyclic intermediates; reactions performed in the presence of 1-nonene show no incorporation of the higher olefin, strongly implicating the involvement of large ring metallacycles.