The novel [(dME)2(HIM)P]2Ti(IV) complex: synthesize, characterization, and its utility in ROP of D,L-lactide

The novel {2,4-bis(1,1-dimethylethyl)-6-{[(2-hydroxyethyl)imino]methyl}phenoxy}(2) titanium(IV) complex {[(dME)(2)(HIM)P](2)Ti(IV)} had been synthesized and characterized by EA, XRF, IR, and NMR methods. The [(dME)(2)(HIM)P](2)Ti(IV) complex was reactive and promoted ring-opening polymerization (ROP) of d,l-lactide in the presence of benzyl alcohol (BnOH). And the results showed that ROP of d,l-lactide were produced upon addition of an excess (1-8 equiv.) of external BnOH. The complex showed a living and controlled fashion (M (w)/M (n) = 1.15-1.32) for ROP of d,l-lactide and could produce the poly(d,l-lactide) with average molecular weight (M (n)) up to 8.87 x 10(4) g mol(-1). The mechanism study by H-1 NMR spectrum of poly(d,l-lactide) with terminal benzyl ester group and [(dME)(2)(HIM)P](2)Ti(IV) complex revealed that the polymerization proceeded through the traditional activated monomer mechanism and the acyl-oxygen bond cleavage mode of monomer. And the C-13 NMR spectra and TG/DSC analysis showed that poly(d,l-lactide) was essential atactic and thermal stable polymer.