Highly cis-1,4 selective polymerization of 1,3-butadiene with Co(II) complexes bearing N-aryl-phenanthrene-o-iminoquinones.

A series of cobalt(II) complexes bearing N-aryl-phenanthrene-o-iminoquinones have been prepared and characterized. The catalyst system (Ar-PI)CoCl(μ-Cl) 2 ClCo(Ar-PI)/MAO shows good catalytic activity and cis ‐1,4 selectivity (up to 96.2%) for 1,3‐butadiene polymerization. Several chlorine-bridging dinuclear Co(II) complexes bearing the Schiff base ligands N-aryl-phenanthrene-o-iminoquinones (Ar-PICoCl 2) were synthesized and characterized by elemental analyses, infrared analyses and X-ray crystallography. The X-ray crystallography analysis of Co(II) complex 2 revealed that the geometry around the cobalt centers is twisted quadrilateral configuration. Upon activation with MAO, these complexes showed good activities (82.5–98.3%) for 1,3-butadiene polymerization affording predominantly cis -1,4 polybutadiene (up to 96.2%). GPC showed that the polybutadiene have relatively narrow PDI (Mw/Mn = 1.20–2.21). [ABSTRACT FROM AUTHOR]