Copolymerization of Ethylene with Polar Monomers by Anionic Substitution. Theoretical Study Based on Acrylonitrile and the Brookhart Diimine Catalyst

• Published in: Organometallics 2005-04, Vol.24 (9), p.2147-2156
• Main Authors: Szabo, Miklos J., Galea, Natasha M., Michalak, Artur, Yang, Sheng-Yong, Groux, Laurent F., Piers, Warren E., Ziegler, Tom
• Format: Article
• Language: English
• ISSN: 0276-7333; 1520-6041
• DOI: 10.1021/om049018z

Calculations have been carried out on the complexation energy of acrylonitrile and ethylene using derivatives of the cationic N∧N Ni(II)−diimine Brookhart complex. For acrylonitrile (CH2CHCN) considerations were given to both π binding through the olefinic CC functionality and σ binding through the NC group. The diimine ring system N∧N = −NR‘ ‘CR1CR2NR‘ ‘ with R‘ ‘ = 2,6-C6H3(i-Pr)2 and R1, R2 = CH3 was functionalized by substituting a carbon in the diimine ring by B- and R1 or R2 (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 σ complexation of acrylonitrile, a prerequisite for ethylene/acrylonitrile copolymerization.