Synthesis and structural analysis of phenoxy-substituted half-titanocenes with different anionic ligands, Cp*TiX(Y)(O-2,6-ⁱPr<inf>2</inf>C<inf>6</inf>H<inf>3</inf>): Effect of anionic ligands (X,Y) in ethylene/styrene copolymerization

Abstract

Synthesis and structural analysis of various phenoxy modified half-titanocenes with different anionic ligands of the type, Cp*TiX(Y)(O-2,6- i Pr 2 C 6 H 3 ) [X = Y = pyr (2, pyr = C 4 H 4 N), pz (3, C 3 H 3 N 2 ), OPh (4); X = Cl, Y = OCH(CF 3 ) 2 (5)] have been explored. Ethylene/styrene copolymerization by 2, 5, and Cp*TiCl 2 (O-2,6- i Pr 2 C 6 H 3 ) (1) in the presence of [PhN(H)Me 2 ][B(C 6 F 5 ) 4 ] and Al(i-Bu) 3 /Al(n-octyl) 3 afforded poly(ethylene-co-styrene)s as the sole product even at 55 and 70 °C, whereas the pyrazolato analogue (3) showed the negligible activity and 4 afforded a mixture of copolymer and syndiotactic polystyrene: 5 showed the better catalyst performance in terms of activity, suggesting that the anionic ligand (X,Y) plays a role in this catalysis. © 2012 Elsevier B.V.