The union of experimental and computational methods can accelerate the development of polymerization catalysts for industrial applications. Herein, we report complementary experimental and computational studies of the thermal stability of α-diimine nickel complexes by using thermally stable Cat. 1 and a typical Brookhart catalyst (B-Cat) as models. Experimentally, we found that many more nickel atoms could be activated for Cat. 1 at elevated temperature during the ethylene polymerization process compared to those for B-Cat. Computationally, first-principle calculations showed that the decomposition energies of Cat. 1 were found to be higher than those of B-Cat, contributing to the activation observed for Cat. 1. We found that the presence of ethydene evidently affected the conformation of C1-N1-Ni-N2-C2 five-membered ring (where the nickel center is located) of Cat. 1, turning the envelope conformation (B-Cat) into a half-chair conformation (Cat. 1). According to calculations, the decomposition energy of the latter was 17.4 kJ/mol higher than that of the former. These results provide information to elucidate the mechanism of thermal stability of α-diimine nickel catalyst and significantly advance the development of thermally stable α-diimine nickel catalysts used in industry.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry