Ti(IV)-silyliminophenolate catalysts for ε-caprolactone and L-Lactide polymerization

In this study, titanium (IV) silyliminophenolate complexes were synthesized by reactions of titanium (IV) isopropoxide with silyliminophenolate (SPIMPH2), and its 3-methoxy, 4-hydroxy, 5-bromo, 4-methyl, and 3-tert-butyl derivatives in isopropanol, respectively. The structures of compounds were elucidated by spectroscopic (FTIR, H-1, and C-13 NMR) studies, thermal analysis (elemental and thermogravimetric), and mass spectrometry. Titanium (IV) silyliminophenolate complexes together with or without 9-anthracenemethanol (9-AnOH) are active catalyst systems for the ring-opening polymerization of epsilon-caprolactone (epsilon-CL) and L-lactide (LLA). Titanium complexes as catalysts showed moderate activity with 10-100% conversion of epsilon-caprolactone, L-lactide and co-monomers of epsilon-CL/LLA depending on temperatures, times, and the substituents on the iminophenol moiety. In addition to spectroscopic methods, gel permeation chromatography (GPC) was also used in the characterization of resulting polymers (PCL, PLLA, and Co-PCL/PLLA).