Controlled Radical Polymerization of Vinyl Acetate Mediated by a Bis(imino)pyridine Vanadium Complex

Source type: Prin

Homo e Copolymerisation of Butadiene catalysed by an Bis(imino)pyridyl Vanadium Catalyst

The bis(imino)pyridyl vanadium(III) complex [VCl 3-{2,6-bis[(2,6-iPr2C6H 3)N=C(Me)]2(C5H3N)}] activated with different aluminium cocatalysts (AlEt2Cl, Al2Et 3Cl3, MAO) promotes chemoselective 1,4-polymerization of butadiene with activity values higher than classical vanadium-chloride-based catalysts. The polymer structure depends on the nature of the cocatalyst employed. The MAO-activated complex was also found to be active in ethylene-butadiene copolymerization, producing copolymers with up to 45 mol-% of trans-1,4-butadiene. Crystalline polyethylene and trans-1,4-poly(butadiene) segments were detected in these copolymers by DSC and 13C NMR spectroscopy

"Imine-based Vanadium Catalysts for alpha-olefin Polymerization"

Advances over the last decade in the development of vanadium-based pro-catalysts bearing ligands containing the imine functionality are discussed in terms of their synthesis, characterization and their ability to oligmerize/polymerize a-olefins. The chapter is organized by ligand type, considering initially ligands which chelate (bi- and tri-dentate) only through nitrogen centres, before discussing those binding via nitrogen and oxygen (bi-, tri- and tetra-dentate), those with nitrogen, oxygen and sulfur donors (penta- and hexa-dentate) and finally a number of ligand systems which are either mono-dentate or for which the term imine can be more loosely applied, such as the heterocycle pyridine