Large-ring P/O chelate nickel complex catalyzed oligomerization of ethylene to linear ?-olefins

1,1-(Bicyclononyl-9-phosphino)hendecanoic acid and potassium 1,1-(biscyclohexylphosphino)­hendecylate were synthesized. A model nickel complex [η3−C8H13]Ni[(C8H14)P(CH2)10COO] containing a 14-membered chelate ring was also synthesized. The catalytic activity of this large chelate ring nickel complex for the oligomerization of ethylene was studied and compared with that of six-membered ring chelate nickel complexes. The influence of the chelate ring was rationalized in terms of intramolecular rotation. The 14-membered ring P/O chelate nickel complex was shown to have efficient catalytic activity for the oligomerization of ethylene to α-olefins.