Polymerization of isoprene initiated by the reaction products of zirconium allylic complexes and titanium chlorides

Reaction of (all)₄Zr with TiCl₄ involves the migration of the allyl ligands to titanium which is accompanied by the reduction of titanium to a tri- and divalent state and the formation of diallyl. The reaction products are found to initiate polymerization and oligomerization of isoprene. The course of the isoprene reactions and the properties of the resulting polymers are determined by the nature of the complexes formed. The reaction products of TiCl₄ or TiCl₃ with (all)₂ZrCl₂ initiate cationic polymerization of isoprene. Complexes resulting from the reaction of TiCl₃ with (all)₄Zr or (all)₃ZrCl lead to cis-1,4-polyisoprene.