Ethylene polymerization promoted by dinuclear titanium p-tert-butylthiacalix[4]arene complexes

The dinuclear titanium p-tert-butylthiacalix4]arene complexes 1 and 2 after activation with methylaluminoxane have been tested as homogeneous catalysts for the polymerization of ethylene. The results show that the catalytic activity of 1, although still poor, is higher than those of the related mononuclear titanium complexes bearing calix4]arene as ligand. The molecular weight of the polyethylene produced are high (M_W up to 1.4 × 10⁶ Dalton) with broad molecular weight distribution. The polyethylenes have high melting point (133-142 °C) indicating a linear polymer microstructure which was confirmed by ¹³C NMR analysis.