Methylene bridged binuclear bis(imino)pyridyl iron(II) complexes and their use as catalysts together with Al(i-Bu)3 for ethylene polymerization
- 作者：Lincai Wang ; Junquan Sun
- 关键词：Iron ; Binuclear catalysts ; Bis(imino)pyridyl complexes ; Bimodal polyethylene ; Ethylene polymerization
- 刊名：Inorganica Chimica Acta
- 出版年：2008
- 期刊代码：40_00201693
- 类别：ch
- 出版时间：20 May 2008
- 卷：361
- 期：7
- 页码：1843-1849
- 文件大小：183 K
摘要
Three novel methylene bridged binuclear iron(II) complexes: 
che/MiamiImageURL/B6TG5-4PTW4W3-3-R/0?wchp=dGLzVzz-zSkWA" alt="View the MathML source" title="View the MathML source" align="absbottom" border="0" height=19 width="924"/>(R,R′ = i-C3H7 (6); R = i-C3H7, R′ = CH3 (7); R,R′ = CH3 (8))} have been synthesized. Activated by Al(i-Bu)3, complex 6 shows very poor activity for the polymerization of ethylene at one bar ethylene pressure, whereas, 7 and 8 exhibit much higher activity than mononuclear iron catalysts {[ArN
C(Me)C5H3N(Me)CNAr′]FeCl2 (Ar,Ar′ = 2,6-C6H3-i-Pr (9); Ar = 2,6-C6H3-i-Pr2, Ar′ = 2,6-C6H3–Me2 (10); Ar,Ar′ = 2,6-C6H3–Me2 (11))}. The molecular weight (Mw) of PE produced by 7 and 8 are in the range 13.2–46.0 × 104 and much higher than those produced by mononuclear iron catalysts 9 and 10. GPC results demonstrate that 7 and 8 yield PE with a broad/bimodal molecular weight distribution (MWD). In contrast, 9 and 10 yield PE with relatively narrow and unimodal MWD (4.26 and 3.55). Elevating the temperature and Al/Fe molar ratio will narrow the MWD of PE.