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.