Synthesis and characterization of 2-imino-indole nickel complexes and their ethylene oligomerization study

A series of 2-imino-indole derivatives and their neutral nickel complexes were synthesized and characterized. A single-crystal X-ray analysis of [Ni(C10H7)(C18H16ClN2)(PPh3)] shows the nickel center adopted a square-planar coordination geometry. The nickel complexes act solely as effective catalysts for ethylene oligomerization with the activity up to 2.05 × 104 g ethylene mol−1 h−1.