Iminopyridine Copper Complex‐Based Catalysts for 1,3‐Dienes Stereospecific Polymerization

Abstract

Some novel copper complexes are synthesized by reacting copper(II) dichloride and copper(II) dibromide with a series of pyridyl-imine ligands differing in the nature of the substituents at the iminic carbon and at the imino nitrogen atom. All the complexes are characterized by analytical and infrared data: for some of them single crystals are obtained, and their molecular structure is determined by X-ray diffraction. The complexes are combined with methylaluminoxane (MAO) for the polymerization of 1,3-dienes (i.e., 1,3-butadiene and isoprene) obtaining active and selective catalysts and, in case of isoprene, polymers with quite unusual structures, i.e., predominantly alternating cis-1,4-alt-3,4 structures containing cis-1,4 units sequences within the polymer chain.

Synthesis of stereoregular polymyrcenes using neodymium-, iron- and copper-based catalysts

“…β-Myrcene (Merck, ≥90% pure) was refluxed over CaH 2 for 3 h, then distilled trap-to-trap and stored under dry nitrogen. Iron, 4 copper 6 and neodymium 3,7 complexes were prepared as already reported in the literature. Methylaluminoxane (MAO) (Aldrich, 10 wt% solution in toluene), tetraisobutylaluminoxane (TIBAO) (Akzo Nobel, 10 wt% solution in cyclohexane) and tetrachloroethane-d 2 (C 2 D 2 Cl 4 ) (Aldrich, >99.5% atom D) were used as received.…”

“…In this context, on the basis of the experience previously acquired in the field of the polymerization of conjugated dienes with iron-, 1–4 copper- 5,6 and neodymium-based catalytic systems, 3,7 we have now examined the polymerization of β-myrcene with catalysts based on pyridyl-imino complexes of neodymium, iron and copper.…”