Sterically modulated binuclear bis-α-diimine Pd(II) complexes: Synthesis, characterization, DFT studies and catalytic behavior towards ethylene oligomerization

•Three new Pd(II) complexes were synthesized and characterized by spectroscopic methods and their structures optimized by DFT calculations.•Pd(II) complexes in combination with EASC showed better performance towards oligomerization of ethylene than MAO.•All the Pd(II) complexes oligomerize ethylene to C4C20 fractions at activities of up to 1218.4 kg-oligomer mol-Pd−1 bar−1 h−1 at 30 °C with EASC.

A series of Pd(II) complexes of bis-α-diimine derivatives with substituent at 2,6-positions of aniline increasing sterically from Me < Et < iPr groups have been synthesized to act as a versatile set of catalytic precursors for oligomerization of ethylene in combination with aluminum activators. Treatment of the bimetallic Pd(II) complexes with ethylaluminum sesquichloride (EASC) or Methylalluminooxane (MAO) in toluene generates active cationic catalyst in situ that oligomerize ethylene to α-olefins. All the Pd(II) complexes efficiently oligomerize ethylene to produce C4C20 fractions at activities of up to 1218.4 kg-oligomer mol-Pd−1 bar−1 h−1 at 30 °C in combination with EASC.

Graphical abstractAll the Pd(II) complexes efficiently oligomerize ethylene to produce C4C20 fractions at activities of up to 1218.4 kg-oligomer mol-Pd−1 bar−1 h−1 at 30 °C in combination with EASC.Figure optionsDownload full-size imageDownload as PowerPoint slide