THEORETICAL STUDIES ON POLYMERIZATION AND CO-POLYMERIZATION PROCESSES CATALYZED BY LATE TRANSITION METAL COMPLEXES


Artur Michalak and Tom Ziegler ,

Department of Chemistry, University of Calgary, Calgary, Alberta, Canada T2N 1N4.

 

We present the results of theoretical studies on the polymerization and co-polymerization reactions of ethene, a-olefins, and acrylates catalyzed by late transition metal complexes. The substituent effects on the factors controling polymer branching, such as relative stabilities of isomeric alkyl and olefin complexes, as well as the regioselectivity of olefin insertion have been studied by gradient corrected DFT calculations for N^N-Pd(II) complexes, with N^N = -NAr-CR-CR-NAr-, Ar = -C6H5, -C6H3(Me)2, -C6H3(i-Pr)2, and R = H, -CH3, C10H6. Further, the growth and isomerisations of polymer chain have been modeled by stochastic approach.

The co-polymerization of a-olefin with acrylates have been studied by DFT calculations for Pd(II) and Ni(II) complexes with Brookhart's and Grubbs' ligands; relative insertion rates and stabilities of intermediates have been determined and compared with the available experimental data. The acrylate binding mode have been compared for a variety of transition-metal based olefin polymerization catalysts, in order to identify those potentially able to catalyze a-olefin co-polymerization with polar group containig monomers.