Ethylene Polymerization Using α-Diimine-Nickel (Ⅱ) Catalyst

My research work was mainly composed of five parts:1. A new α-diimine ligand, bis[N,N′-（4-phenyl-2,6-dimethylphenyl）imino]acenaphthene, and its corresponding Ni（II） complex ({bis[N,N-（4-phenyl-2,6-dimethylphenyl）imino]-acenaphthene} dibromonickel have been synthesizedand characterized. The paramagnetic character of the Ni（II） catalyst makes NMRanalysis impossible. So FT-IR and elemental analysis were used to confine the nickelcomplexes. The crystal structure of the free ligand （1） was determined by X-raycrystallography. In addition, two α-diimine-Ni（II） catalysts,{bis[N,N’-（2,4,6-dimethylphenyl）imino]acenaphthene} dibromonickel and{bis[N,N’-（2,6-dimethylphenyl） imino] acenaphthene} dibromonickel were alsosynthesized and characterized for comparison. Influences of catalyst structure,polymerization conditions and different co-catalyst on ethylene polymerization wereinvestigated. The polyethylene （PE） obtained was characterized by DSC, GPC, andNMR. It was found that modifying the catalysts structure has a great effect oncatalytic activity, PE molecular weight and distribution. The complex{bis[N,N’-（4-phenyl-2,6-dimethylphenyl）imino] acenaphthene}dibromonickel withsterically bulky, electron-donating group phenyl, activated by diethylaluminumchloride （DEAC） was tested in the polymerization of ethylene, showed to be highlyactive （2.97×10⁶g PE/（molNi·h·bar））.2. A new α-diimine ligand, bis[N,N′-（4-phenyl-2,6-dimethylphenyl）imino]-2,3-butadiene, and its corresponding Ni（II） complex3a({bis[N,N-（4-phenyl-2,6-dimethylphenyl）imino]-2,3-butadiene} dibromonickel were synthesized andcharacterized. The crystal structure of L3was determined by X-ray analysis. As acatalyst for the polymerization of ethylene, the complex3a({bis[N,N-（4-phenyl-2,6-dimethylphenyl）imino]-2,3-butadiene} with phenyl groupsshowed to be highly active with DEAC as co-catalyst, when compared to the complex1a {bis[N,N’-（2,6-dimethylphenyl）imino]-2,3-butadiene}dibromonickel and2a{bis[N,N’-（2,4,6-dimethylphenyl）imino]-2,3-butadiene}dibromonickel. It was shownthat effects of electronic and reaction conditions, have substantial influence on theproduct properties and the polymerization activities. In addition, for3a/DEAC catalyst system, at0°C, AI/Ni=800and t=5min, the higher catalytic activity（3.41×10⁶g PE/（mol Ni·h·bar）） was obtained.3. A new α-diimine ligand, bis[N,N′-（6-phenyl-2,4-dimethylphenyl）imino]acenaphthene and its corresponding Ni（II） complex{bis[N,N′-（6-phenyl-2,4-dimethylphenyl）imino]acenaphthene}dibromonickel, weresuccessfully synthesized, and characterized by NMR and elemental analysis.α-Diimine ligand, bis[N,N′-（2,4,6-dimethylphenyl）imino]acenaphthene and itscorresponding Ni（II） complex,{bis[N,N’-（2,4,6-dimethylphenyl）imino]acenaphthene}dibromonickel were also synthesized and characterized as a comparison. The complex{bis[N,N’-（6-phenyl-2,4-dimethylphenyl）imino]acenaphthene}dibromonickel withsterically bulky phenyl groups, activated by diethylaluminum chloride （DEAC） wastested in the polymerization of ethylene, showed to be highly active （3.97×106gPE/（molNi·h·bar））.4. Ligand structure has substantial influence on the product properties and the polymerizationactivities by changing the ligand structure; the structure of the catalyst can be easilychanged to obtain catalysts with different catalytic properties. In this chapter, anumber of α-diimine ligands were synthesized and characterized.5. To develop new tumor targeting macromolecular conjugates,poly（HPMA）-SD-APMA-DTPA （HPMA: N-（2-hydroxypropyl）-methacrylamide;APMA: N-（3-aminopropyl）methacrylamide; DTPA: diethylenetriaminepentaaceticacid; SD: sulfadiazine） was synthesized and characterized. Thepoly（HPMA）-SD-DTPA conjugates were radiolabeled with the radionuclide99mTcand tested for uptake by cultured H22cells in vitro. DTPA-^99mTc （radiotracer1） andpoly（HPMA）-DTPA-^99mTc （radiotracer2） were also synthesized and characterized forcomparison. The uptake of poly（HPMA）-SD-DTPA-^99mTc （radiotracer3,34.76%）was significant higher than that of poly（HPMA）-DTPA-^99mTc （16.40%）, indicatingthat uptake of the poly（HPMA）-SD-DTPA-99mT was active binding. The uptake ofpoly（HPMA）-DTPA-^99mTc was significant higher than that of DTPA-^99mTc （2.98%）,suggesting that uptake of the poly（HPMA）-DTPA-99mT was passive binding. The datasuggest that the poly（HPMA）-SD-APMA-DTPA conjugates might be useful as tumortargeting macromolecular conjugates.