Based on density functional theory computations for polymerization reaction mechanisms via metallocene and neutral salicyladiminato palladium (II) and nickel (II) catalysts

the correlation between regioselectivity and Mulliken site charge in catalyzed olefin polymerization was discussed from the view of reactants and transition states. The effects on regioselectivity of the catalyzed polymerization by reactants and transition states are significantly different.The reactant influences regioselectivity of a reaction by the site charge effect on frontier orbits

while the transition state influences regioselectivity by the site charge delocalization.Different regioselectivity results in two different polymerization mechanisms: 1

2-and 2

1-insertion polymerization mechanisms.1

2-insertion mechanism gives a cation intermediate

while2

1-insertion mechanism gives an anion intermediate.The more delocalized the charge on a cation in the transition state is for a catalyst configuration

the lower the active energy will be for1

2-insertion reaction of that configuration; the more delocalized the charge on an anion in the transition state is

the lower the active energy will be for 2

1-insertion.Thus the regioselectivity is different for different catalyst configurations.And this difference is correlated with the charge distribution in the catalyst.Only Mulliken charges are correlated very well

possibly because it originated from the coefficients of the orbitals.Material design is a very important topic in scientific research.So the conclusions of correlation between regioselectivity and Mulliken site charge in catalyzed olefin polymerization are significant for olefin polymer design.