| 초록 |
In 1954, it was discovered that the catalyst system TiCl4-AlR3 polymerizes isoprene into cis-1,4-polymer. Later it has been found that catalyst systems composed of a Ti, Co, Ni, V, or rare earth metal compound and an organoaluminum give cis-1,4-polybutadiene. Recently new cationic bidentate Ni(II)- and Pd(II)-based α-dimine catalysts were synthesized by Brookhart et al. Some distinguished features of the diimine ligand catalysts are their high electrophilicities, cationic metal center and the use of sterically bulky α-diimine ligands. This type of catalysts is characterized by reduced oxophilicity and thus a higher tolerance for functional groups. The large number of possible variations in these catalyst systems allow for more specifically designed catalysts, possibly selective for the optimized polymerizations of desired conjugated dienes. As a result, we decided to find the efficient catalysis using Ni(II)-based α-diimine complexes for polymerizations of 1,3-butadiene. |
