Journal of Polymer Science Part A: Polymer Chemistry, Vol.52, No.15, 2111-2123, 2014
Olefin Polymerization and Copolymerization by Complexes Bearing [ONNO]-Type Salan Ligands: Effect of Ligand Structure and Metal Type (Titanium, Zirconium, and Vanadium)
A series of novel titanium(IV) complexes bearing tetradentate [ONNO] salan type ligands: [Ti{2,2'-(OC6H3-5-t-Bu)(2)-NHRNH}Cl-2] (Lig(1)TiCl(2): R = C2H4; Lig(2)TiCl(2): R = C4H8; Lig(3)TiCl(2): R = C6H12) and [Ti{2,2'-(OC6H2-3,5-di-t-Bu)(2)-NHC6H12NH}Cl-2] (Lig(4)TiCl(2)) were synthesized and used in the (co) polymerization of olefins. Vanadium and zirconium complexes: [M{2,20(OC6H3-3,5-di-t-Bu)(2)-NHC6H12NH}Cl-2] (Lig(4)VCl(2): M = V; Lig(4)ZrCl(2): M = Zr) were also synthesized for comparative investigations. All the complexes turned out active in 1-octene polymerization after activation by MAO and/or Al(i-Bu)(3)/[Ph3C][B(C6F5)(4)]. The catalytic performance of titanium complexes was strictly dependent on their structures and it improves for the increasing length of the aliphatic linkage between nitrogen atoms (Lig(1)TiCl(2) << Lig(2)TiCl(2)