Titanium complexes bearing carbamato ligands as catalytic precursors for propylene polymerization reactions

This report describes propylene polymerization reactions with titanium complexes bearing carbamato ligands, Ti(O2CNMe2)Cl2 (I) and Ti(O2CR2)4 [R2 = NMe2 (II), NEt2 (III) and image (IV)]. Combinations of these complexes and MAO form catalysts for the synthesis of atactic polypropylene, as confirmed by FT-IR, DSC and 13C NMR analysis. Effects of main reaction parameters on the catalyst activity were studied including the type of complex, solvent, temperature, and the [Al]/[Ti] molar ratio. The highest activity was observed when chlorobenzene was used as a solvent and AlMe3-depleted MAO was employed as a cocatalyst.