LII.: Synthesis and characterization of bis- and mono-(η3-allyl)neodymium(III) chloride, Nd(η3-C3H5)2Cl•1.5 THF and Nd(η3-C3H5)Cl2•2THF, for preparation of highly active and selective complex catalysts for 1,4-cis-polymerization of butadiene

The title complexes are obtainable by comproportionation reaction from Nd(eta(3)-C3H5)(3).Dioxan and NdCl3 . 2THF in the correspond ing molar ratio in tetrahydrofuran (THF) in very good yields. The characterization was done by elementary analysis, IR and H-1 NMR spectroscopy and for the bis(eta(3)-allyl) complex also by X-ray crystal structure analysis. In combination with methylaluminoxane (MAO) both complexes catalyze the 1.4-cis-polymerization of butadiene in toluene and heptane, respectively, with an extremely high activity and a selectivity up to 98%. The catalyst formation results from anion transfer to the Lewis-acid methylaluminoxane giving a cationic mono(eta(3)-allyl)neodymium(III) fragment, which is stabilized by coordinative interactions with the complex counter anion. (C) 1998 Elsevier Science S.A.