Synthesis of cationic nickel(II) compounds for butadiene polymerization

Abstract

ABSTRACTA series of cationic nickel(II) compounds with various counter ions ([BF4]–, [CF3SO3]–) and N‐bearing ligands (1,10‐phenanthroline, benzimidazole and terpyridine) were synthesized. The simple compound, Ni(Phen)2Cl2, was prepared as a reference compound. All title compounds were characterized by elemental analysis, and infrared spectra analyses and compounds, some specific ones, were further examined by X‐ray crystallographic analysis. Upon treatment with ethylaluminum sesquichloride, these nickel(II) compounds exhibited high activities (up to 88.5%/4 h) for butadiene polymerization and afforded liquid polybutadiene (Mw < 30,000) with a high cis‐content (up to 92.1%). Various polymerization conditions were investigated in detail, and it was found that less steric hindrance of the ligands enhanced the catalytic activities of the nickel(II) compounds. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40511.