| 초록 |
The vast economic importance of polyolefins is reflected by an annual production of more than 70 million tons of polyethylene and polypropylene. The major portion of these materials is produced by catalytic polymerization, employing Ziegler or Phillips catalysts based on early transition metals(Ti, Zr, Cr, V), Over the past decade, Brookhart reported on ethylene and 1-olefin polymerization by cationic Ni(Ⅱ), Pd(Ⅱ) complexes with diimine ligands. Comparing to early transition metal complexes, they are much less oxophilic and more tolerant toward polar reagents. Here we synthesized new types of catalyst by neutral nickel(Ⅱ) complexes of bidentate ligands comprising a diazene function –N=N- as a donor. The ligands were prepared from diamine and aniline by azo coupling. Nickel(Ⅱ) complexes were obtained by reaction of the ligand with 1 equiv of (DME)Ni(Ⅱ)Br2 in the presence of CH2Cl2. |
