The synthesis and characterization of LTi(O-i-Pr)2 (1) and LTiCl2 (2) complexes containing a new [ONNO]-type tetradentate diamine–diethanolate ligand such as (HOCMe2CH2NMeCH2CH2NMeCH2CMe2OH) (LH2) was achieved. Single-crystal X-ray analyses revealed that monomeric complexes 1 and 2 had pseudo-C2 and pseudo-C1 symmetric distorted octahedral geometry, respectively. Interestingly, complex 1 has fac–fac geometry for tetradentate L around a Ti centre in both solid and solution, whereas complex 2 has different geometry in solid (mer–fac, C1) and solution (fac–fac, C2). They are effective catalysts for the controlled ring opening polymerization of L-lactide, as shown by the linearity of the number average of the molecular weight of polylactides versus conversion, as well as narrow PDI values.
Dalton Transactions
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