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Synthesis , structure , and catalytic properties of ansa-zirconocenes , Me 2 Si ( RInd ) 2 ZrCl 2 ( R = 2-por 3p-tolyl )
| Content Provider | Semantic Scholar |
|---|---|
| Author | Yoon, Sung Cheol Park, Je-Woo Jung, Hyun Sook Song, Hyunjoon Park, Joon Taek Woo, Seong Ihl |
| Copyright Year | 1998 |
| Abstract | ansa-Ligands, Me2Si(RInd)2 [R=2-p (1) and 3-p-tolyl (2)], have been prepared as a mixture of racand meso-isomers in a ratio of 1:1 from the reactions of Me2SiCl2 with cyanocuprates of 1-p-tolylindene and 2-p-tolylindene in diethyl ether, respectively. Pure rac-isomers, 1r and 2r, have been isolated by fractional recrystallization of 1 and 2. Thermal diastereomerization of 1 and 2 between racand meso-isomers has been studied by H-NMR spectroscopy. These results imply that 1 and 2 undergo the diastereomerization process by migration of silicon moiety and hydrogen atom, respectively. ansa-Zirconocenes, Me2Si(RInd)2ZrCl2 [R=2-p (3) and 3-p-tolyl (4)], have been prepared from the reactions of the corresponding dilithiated ligands with ZrCl4 in diethyl ether and hexane at −78°C. The molecular structure of rac-3 has been determined by a single crystal X-ray diffraction study. Propylene polymerization has been studied using rac-3 and meso-4 in the presence of methylaluminoxane (MAO). Catalyst rac-3 produces a highly isotactic polypropylene (PP) at 0°C by the enantiomorphic site control mechanism and meso-4 affords a syndiotactic dominant PP having a rr triad of 49% at −30°C by the chain end control mechanism. © 1998 Elsevier Science S.A. All rights reserved. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://koasas.kaist.ac.kr/bitstream/10203/20142/1/Synthesis,%20Structure,%20and%20Catalytic%20Properties%20of%20ansa-zirconocenes,%20Me2Si(RInd)2ZrCl2%20(R%20=%202-p-%20or%203-p-toly).pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
