Studies of polymerization of α-olefins carried out with a tri-nuclear nickel cluster.

Green coloured crystals of μ3-chloro-μ3-hydroxotris (μ-chloro) tris(N,N,N’,N’ –tetramethyl ethylene-1,2-diamine) trinickel(II) chloride (1) were synthesized and used as a pre-catalyst, along with methylaluminoxane (MAO) as an initiator, to polymerize styrene and methyl methacrylate. Polystyrene prepared from these Ni catalyzed reactions are highly syndiotactic with some atactic nature. Blue coloured acetonitriletri(aqua) (N,N,N’N’ -tetramethylethylenediamine) nickel (II) chloride (2) has also been synthesized and structurally characterized by X-ray crystallography. Co-polymerization of methyl methacrylate and styrene was also successfully carried out with the MAO-activated 1. The polymerization kinetics of styrene was studied by molecular weight analysis. Effects of changing the temperature and monomer concentration on the polymerization would be discussed. Polymerization carried out in homogeneous fashion and a mixed system containing both heterogeneous and homogeneous system will also be discussed.