Kulyabin Pavel S, Izmer Vyatcheslav V, Goryunov Georgy P, Sharikov Mikhail I, Kononovich Dmitry S, Uborsky Dmitry V, Canich Jo Ann M, Voskoboynikov Alexander Z
Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory 1/3, Moscow 119991, Russia.
Baytown Technology and Engineering Complex, ExxonMobil Chemical Company, 5200 Bayway Drive, Baytown, Texas 77520, USA.
Dalton Trans. 2021 May 11;50(18):6170-6180. doi: 10.1039/d1dt00645b.
In this work we systematically studied the effects of modifications of substituents on the performance of the isospecific zirconocene-based catalyst family, Me2Si(2-Alk-4-(N-carbazolyl)Ind)ZrX2 (X = Cl, Me), wherein the progenitor was shown to be particularly suitable in high-temperature propylene polymerization processes. In order to obtain the required zirconocenes, we developed a novel synthetic pathway to 4-(N-carbazolyl)indenes through Pd-catalyzed cyclizations of 2,2'-dibromobiaryls with 4-aminoindenes, which were synthesized via Buchwald-Hartwig reaction or electrophilic amination of 4-indenyl Grignard reagents with trimethylsilylmethyl azide. By a number of examples, the anion-promoted rac-to-meso isomerization method was shown to work reliably well for preparation of rac-ZrMe2-complexes. Certain zirconocenes among the 21 tested in propylene polymerization at 70 and 100 °C under MAO or borate activation outperformed the parent catalyst in molecular weight capability, regio- or stereoselectivity.
在本工作中，我们系统地研究了取代基修饰对基于等规锆茂的催化剂家族Me2Si(2-Alk-4-(N-咔唑基)茚)ZrX2（X = Cl，Me）性能的影响，其中已表明该母体催化剂特别适用于高温丙烯聚合过程。为了获得所需的锆茂，我们开发了一种新颖的合成途径，通过2,2'-二溴联芳基与4-氨基茚的钯催化环化反应来制备4-(N-咔唑基)茚，4-氨基茚是通过Buchwald-Hartwig反应或4-茚基格氏试剂与三甲基硅基甲基叠氮的亲电胺化反应合成的。通过多个实例表明，阴离子促进的外消旋体到内消旋体异构化方法在制备外消旋ZrMe2配合物方面可靠且效果良好。在70和100°C下用MAO或硼酸盐活化进行丙烯聚合测试的21种锆茂中，某些锆茂在分子量能力、区域或立体选择性方面优于母体催化剂。
