Synthesis of titanium, zirconium, and hafnium complexes that contain the [(mesitylN-o-C6H4)(2)O](2-) ligand

(MesitylNH-o-C6H4)(2)O (H-2[MesNON]) has been synthesized in similar to 70% yield, and several [MesNON](2-) complexes of Ti, Zr, and Hf have been prep ared, in particular a variety of dialkyl complexes, [MesNON]MR2 (M = Zr, R = Me, CH2CMe3, Ph; M = Hf, R = Me, Et, CH2-CHMe2, CH2CMe3, Ph). [MesNON]ZrM e2 can be activated with [Ph3C][B(C6F5)(4)] or [PhNMe2H]-[B(C6F5)(4)], but the resulting cationic species will only oligomerize l-hexene. We conclude that the sterically bulky tert-butyl groups in [(R'N-o-C6H4)(2)O](2-) syste ms are necessary for the success of [R'NON](2-) Zr catalyst systems for the living polymerization of 1-hexene.