STEREOSELECTIVE POLYMERIZATION OF BUTADIENE BY A NEW DICATIONIC NICKEL-COMPLEX

The new dicationic nickel complex [dppfNi(MeCN)(4)[BF4](2) (dppf = 1,1 '-bis(diphenylphosphino)ferrocene) in the presence of diethylaluminium chloride (AlEt(2)Cl) exhibited high activity on the 1,3-butadiene pol ymerization. Reaction time, temperature and aluminium/nickel molar rat io were optimized in order to achieve maximum activity and selectivity . Conversions higher than 90% were obtained in contrast to other nicke l-based systems using phosphine ligands, the resulting polybutadiene s howed high cis-1,4 (>80%) content and only small amount of 1,2-units ( 2%). All polymers presented low molecular weights (M(w) < 11800).