Synthesis, characterization, and catalytic activities in syndiospecific polymerization of styrene for half-sandwich titanium complexes with non-Cp tridentate dianionic ligands MeN(CH2CR2O−)2

New half-titanocenes, Cp∗TiCl[(OCR2CH2)NMe(CH2CR′2O)] [R,R′ = H (1), R,R′ = Me, H, (2), R,R′ = Me (3)], were prepared from Cp∗TiCl3 (4) with the corresponding alcohols in the presence of triethylamine. X-ray analysis shows that 1 has slightly distorted trigonal bipyramidal geometry around Ti. These complexes exhibited moderate catalytic activities for syndiospecific styrene polymerization in the presence of MAO and the activity increased in the order: 2 > 1 > 4 > 3 (at 50 °C), 1 > 2 > 4 > 3 (at 70 °C and 90 °C).