Activation effect of metal chlorides in post-metallocene catalytic systems for ethylene polymerization: A DFT study

Abstract This work is devoted to the DFT study of the activation effect of metal chlorides (MgCl 2 , LiCl, ZnCl 2 , CaCl 2 ) in ethylene polymerization reactions on post-titanocene complexes LTi(Y)Cl ( 1 ), where L is the bidentate saligenin type ligand, Y is alkyl group or Cl. The activation effect of metal chlorides is caused by secondary complexation reactions between 1 and metal chlorides. In accordance with previously reported experimental data, our DFT calculations predict that the most probable catalytic particles in the systems based on MgCl 2 possess higher reactivity with respect to ethylene molecule than in the systems based on LiCl. One could expect a higher catalytic activity for CaCl 2 than for MgCl 2 , but for ZnCl 2 the catalytic activity should be the lowest. Results of our calculations show that at least three different hetero-trinuclear compounds of Ti, Mg and Al have similar reactivity towards ethylene molecule. This result explains M w /M n indexes >2 measured earlier for one of the systems under the study with R 3 Al (R = Me, t -Bu) as activators.