Bis(1,3-di-tert-butylimidazolin-2-iminato) titanium complexes as effective catalysts for the monodisperse polymerization of propylene

Manab Sharma, Haneen Simaan Yameen, Boris Tumanskii, Sabina Alexandra Filimon, Matthias Tamm, Moris S. Eisen

نتاج البحث: نشر في مجلةمقالةمراجعة النظراء

ملخص

The use of bis(1,3-di-tert-butylimidazolin-2-iminato) titanium dichloride (1) and dimethyl (2) complexes in the polymerization of propylene is presented. The complexes were activated using different amounts of methylalumoxane (MAO), giving in each case a very active catalytic mixture and producing polymers with a narrow molecular weight distribution (polydispersity = 1.10). The use of the cocatalyst triphenylcarbenium (trityl) tetra(pentafluorophenyl)borate totally inhibits the reaction, producing the corresponding bis(1,3-di-tert- butylimidazolin-2-iminato) titanium(III) methyl complex, the trityl radical (CPh3), the anionic MeB(C6F5)4 -, B(C6F5)3, and the bis(1,3-di-tert-butylimidazolin-2-iminato) titanium(IV) dimethyl·B(C 6F5)3 complex. The use of a combination of physical methods such as NMR, ESR-C60, and MALDI-TOF analyses enabled us to propose a plausible mechanism for the polymerization of propylene, presenting that the polymerization is mainly carried out in a living fashion. In addition, we present a slow equilibrium toward a small amount of a dormant species responsible for 2,1-misinsertions and chain transfer processes.

اللغة الأصليةالإنجليزيّة
الصفحات (من إلى)17234-17244
عدد الصفحات11
دوريةJournal of the American Chemical Society
مستوى الصوت134
رقم الإصدار41
المعرِّفات الرقمية للأشياء
حالة النشرنُشِر - 17 أكتوبر 2012

All Science Journal Classification (ASJC) codes

  • !!General Chemistry
  • !!Biochemistry
  • !!Catalysis
  • !!Colloid and Surface Chemistry

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