Titanium(IV) and Zirconium(IV) amido complexes derived from the azaoxa macrocycle 3,3-dimethyl-1,5-diaza-8-oxacyclodecane

The novel tridentate azaoxa macrocycle O(NH)2], 3,3-dimethyl-1,5-diaza-8-oxacyclodecane, can be singly or doubly lithiated with (n)BuLi at the secondary amine N atoms, giving O(NH)N]Li and O(N)2]Li2, respectively, and further elaborated with introduction of TMS substituents via reaction with (TMS)Cl. Aminolysis of Ti(NMe2)2Cl2] or Zr(NR2)2Cl2(THF)2] with O(NH)2] in toluene gave the distorted octahedral MO(NH)N](NR2)Cl2 (M = Ti, R = Me; M = Zr, R = Me or Et), in which the macrocycle functions as a monoanionic ligand via an amido, an amine, and an ether functionality. Salt metathesis of Zr(NEt2)2Cl2(THF)2] with O(NH)N]Li in toluene afforded Zr(O(NH)N)](NEt2)2Cl, the structure of which also confirms tridentate macrocycle coordination via one amido, one amine, and one ether group; in contrast, analogous salt metathesis involving Zr(NEt2)2Cl2(THF)2] and O(N)2Li2] gave the "sandwich" complex (ON2)2Zr], with the macrocycle behaving as a dianionic ligand (Porter, R. M.; et al. Dalton Trans. 2005, 427). Finally, treatment of O(NH)2] with AlMe3 gave the simple donor-acceptor adduct O(NH)2]AlMe3, which resisted alkanolysis by prolonged heating. In the presence of MAO the new zirconium, titanium, and aluminum complexes show low activity in the polymerization of ethylene.