Copolymerization of ethylene with polar monomers by anionic substitution. Theoretical study based on acrylonitrile and the Brookhart diimine catalyst

Calculations have been carried out on the complexation energy of acrylonitrile and ethylene using derivatives of the cationic (NN)-N-boolean AND Ni(II)-diimine Brookhart complex. For acrylonitrile (CH2=CHCN) considerations were given to both T binding through the olefinic C=C functionality and a binding through the NC group. The diimine ring system (NN)-N-boolean AND = -NR''CR1-CR2NR'' with R'' = 2,6-C6H3(i-Pr)(2) and R-1, R-2 = CH3 was functionalized by substituting a carbon in the diimine ring by B- and R-1 or R-2 (or both) by anionic groups (BF3-, OBF3-, etc.). Substitutions were also carried out at the aryl rings by replacing H or i-Pr with anionic groups. The objective has been to find substitutions that would reduce or eliminate the preference for a complexation of acrylonitrile, a prerequisite for ethylene/acrylonitrile copolymerization.