Efficient Norbornene (NBE) Incorporation in Ethylene/NBE Copolymerization by Half-Titanocene Catalysts Containing Chlorinated Aryloxo Ligands

Synthesis and structural: analysis of a series of half-titanocenes containing chlorinated phenoxy ligands of the type Cp'TiCl2(OAr) [Cp' = Cp, Ar = 2,6-Cl2C6H3 (1), 2,4,6-ClO6H2 (2), C6Cl5 (3); Cp' = indenyl, Ar = 2,6-C12C6H3 (4), 2,4,6-Cl3C6H2 (5), C6Cl5 (6)] and CpTiMe2(OAr) [Ar = 2,4,6-O3C6H2=(9), C6Cl5 (10)] have been explored. The T1 O bond distances in 1H3 are apparently longer than those of the reported aryloxo-modified half-titanocenes, and the Ti O C(in phenyl) angles in 1-3 are also rather small: The Cp analogues (1-3) exhibited higher catalytic activities than the reported (indenyl)TiCl2(O-2,64r2C(6)H(3)) in ethylene copolymerization with norbornene (NBE) in the presence of MAO; these complexes (1-3) also showed better NBE incorporation than those repOrted previously.