Metal dependent control of cis-/trans-1,4 regioselectivity in 1,3-butadiene polymerization catalyzed by transition metal complexes supported by 2,6-bis[1-(iminophenyl)ethyl]pyridine
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- 作者：Dirong Gong ; Baolin Wang ; Chenxi Bai ; Jifu Bi ; Feng Wang ; Weimin Dong ; Xuequan Zhang ; Liansheng Jiang
- 关键词：Organometallic catalyst ; 1 ; 3-Butadiene ; Polybutadiene
- 刊名：Polymer
- 出版年：2009
- 出版时间：10 December 2009
- 年：2009
- 卷：50
- 期：26
- 页码：6259-6264
- 全文大小：227 K
文摘
Fe(III), Cr(III), Fe(II), Co(II) and Ni(II) chloride complexes supported by 2,6-bis[1-(iminophenyl)ethyl]pyridine have been synthesized and characterized along with single crystal X-ray diffraction. These complexes, in combination with MAO, have been examined in butadiene polymerization. The catalytic activity and regioselectivity are strongly controlled by metal center and cocatalyst (MAO/Co ratio dependent in the case of Co(II) complex). The activity decreases in the order of Fe(III) > Co(II) > Cr(III) ≈ Ni (II) complexes, in consistent with the space around the metal center. Polybutadiene with different microstructure content, from high trans-1,4 units (88–95 % for iron(III) and Cr(III)), medium trans-1,4 and cis-1,4 units (55 % and 35 % , respectively, for iron(II)) to high cis-1,4 units 79 % for Co(II) and 97 % for Ni(II) can be easily achieved by varying of the metal center. In addition, mechanism speculation is also presented to elucidate the dependence of catalytic behaviors on metal and cocatalyst.