| 초록 |
Palladium complexes bearing abnormal imidazo[1,5-a]pyridine-based N-heterocyclic carbene ligands (aImPy) were developed for the homopolymerization of olefins and the copolymerization of olefins and polar monomers. The highly electron-donating nature of these abnormal N-heterocyclic carbenes (aNHCs) embedded in the carbene-phenolate chelating ligand scaffold resulted in good catalytic activity, generating linear polyethylene with a high molecular weight (Mn = 237,000). aImPy-Pd complexes efficiently catalyzed propylene polymerization to afford polypropylene free of regio-defects. These catalytic systems exhibit good tolerance of various polar monomers and afford the desired copolymers. Up to 3.0% of the polar monomers were incorporated into the main chain, as determined by 1H and 13C NMR analysis. Furthermore, methyl methacrylate (MMA), as a 1,1-disubstituted ethylene derivative, was successfully incorporated into the main chain of polyethylene. |
