Synthesis, characterization, and polymerization activity of (pentamethylcyclopentadienyl)titanatranes containing {(O-2,4-Me2C6H2-6-CH2)nN(CH2CH2O)3−n}3− (n = 0–2) or {N(C6H4-2-O)3}3−

(Pentamethylcyclopentadienyl)titanatranes, Cp∗Ti{(O-2,4-Me2C6H2-6-CH2)nN(CH2CH2O)3−n} (n = 0, 1; n = 1, 2; n = 2, 3), featuring three five-membered chelating rings (1) to two six-membered chelating rings (3) in a stepwise fashion through 2 were synthesized from the corresponding tri-hydroxy chelating ligands 1L–3L, respectively, using Cp∗TiCl3 and triethylamine. Cp∗Ti{(O-2-C6H4)3N} (4) having three five-membered chelating rings from fully deprotonated N(C6H4-2-OH)3 (4L) was also synthesized. X-ray analysis shows that 2 and 4 have slightly distorted trigonal bipyramidal geometry around Ti. These compounds exhibited good catalytic activity for the syndiospecific polymerization of styrene in the presence of MAO at various polymerization conditions.