Synthesis, characterization and ethylene oligomerization studies of nickel(II) based new formazane derivatives

► A series of nickel(II) complexes based novel mono- and bis-formazan ligands has been synthesized. ► The catalytic activity depends on the nature of substitutes in the ligand and the amount of active metal centers as well. ► The products of reaction are a mixture of higher α- and β-olefins (butenes, hexenes, octenes) and alkyltoluenes.