as series of novel late transition metal catalysts for olefin oligomerization have been invented . the catalyst system includes a group 8 , 9 or 10 transition metal and an activator . the catalysts demonstrate high activity and selectivity for linear α - olefins . preferably this invention relates to a catalyst system comprising the reaction product of : an activator selected from the group consisting of alumoxane , aluminum alkyl , alkyl aluminum halide , alkylaluminum alkoxide , discrete ionic activator , and lewis acid ; and a catalyst precursor wherein the catalyst precursor has the following formula : wherein m is a group - 8 , - 9 , or - 10 transition metal ; n is nitrogen p is phosphorus ; r 1 , r 2 , r 3 , and r 4 are independently hydrocarbyl radicals ; y is a hydrocarbyl bridge comprising a backbone wherein the backbone comprises a chain that is four or more carbon atoms long ; x are independently abstractable ligands .