Activation of rac-Me2Si(ind)2ZrCl2 by Methylalumoxane Modified by Aluminum Alkyls: An EPR spin-Probe, 1H NMR, and Polymerization Study | Sciact - CRIS-система Института катализа

Activation of rac-Me2Si(ind)2ZrCl2 by Methylalumoxane Modified by Aluminum Alkyls: An EPR spin-Probe, 1H NMR, and Polymerization Study Научная публикация

Журнал

Macromolecular Chemistry and Physics
ISSN: 1022-1352 , E-ISSN: 1521-3935

Вых. Данные

Год: 2006, Том: 207, Номер: 3, Страницы: 327-335 Страниц : 9 DOI: 10.1002/macp.200500443

Ключевые слова

ESR/EPR, Intermediate, Metallocene catalysts, Methylaluminoxanes, NMR, Polymerization

Авторы

Bryliakov Konstantin P. ¹ , Semikolenova Nina V. ¹ , Panchenko Valentina N. ¹ , Zakharov Vladimir A. ¹ , Brintzinger Hans H. ² , Talsi Evgenii P. ^1,3

Организации

1	Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russian Federation
2	Fachbereich Chemie, University of Konstanz, D-78457 Konstanz, Germany
3	Department of Natural Sciences, Novosibirsk State University, 630090, Novosibirsk, Russian Federation

Информация о финансировании (2)

1	Российский фонд фундаментальных исследований	03-03-33034
2	International Association for the Promotion of Co-operation with Scientists from the New Independent States of the Former Soviet Union	00-841

Summary: Solutions containing mixtures of methylalumoxane (MAO) and iBu3Al give rise to 1H NMR signals indicative of the presence of the mixed alkyl aluminum dimers iBu2Al(µ-Me)2AliBu2 and of mixed clusters of the type (AlMe(1 + 2x − y)iBuyO(1 − x))n. These mixed clusters, as well as related species present in solutions containing either MAO–Et3Al or commercially available modified MAO (MMAO), appear to have stronger Lewis acidic sites and greater hydrodynamic radii than comparable clusters present in solutions of MAO alone, as judged from EPR signals observed in these solutions upon addition of TEMPO. When (SBI)ZrCl2 (SBI = rac-Me2Si(ind)2) is reacted with one of these mixed activator reagents, the mixed heterobinuclear cation [(SBI)Zr(µ-Me)2AlMeiBu]+ appears to be formed, together with its methyl counterpart [(SBI)Zr(µ-Me)2AlMe2]+, which is normally predominant in the (SBI)ZrCl2/MAO system at [Al]MAO/[Zr] ratios above 100. In the presence of iBu3Al, the formation of heterobinuclear cations is suppressed in favor of ion pairs containing the cation [(SBI)ZrMe]+ in contact with a (MAO–TIBA)-derived counter anion. The greater reactivity of these contact-ion pairs, as compared to the normally prevalent AlMe3 adducts, as well as an increased Lewis acidity of MMAO, and the ensuing decreased coordination ability of the [Me-(MAO–TIBA)]− counter ion as compared to [Me-MAO]−, are likely to contribute to the positive effects of TIBA additions on the co-catalytic activity of MAO.

Bryliakov K.P. , Semikolenova N.V. , Panchenko V.N. , Zakharov V.A. , Brintzinger H.H. , Talsi E.P.
Activation of rac-Me2Si(ind)2ZrCl2 by Methylalumoxane Modified by Aluminum Alkyls: An EPR spin-Probe, 1H NMR, and Polymerization Study

Macromolecular Chemistry and Physics. 2006. V.207. N3. P.327-335. DOI: 10.1002/macp.200500443 WOS Scopus РИНЦ CAPlusCA OpenAlex

Полный текст от издателя

Поступила в редакцию:	27 сент. 2005 г.
Принята к публикации:	11 нояб. 2005 г.
Опубликована online:	19 янв. 2006 г.
Опубликована в печати:	3 февр. 2006 г.

Web of science:	WOS:000235473400008
Scopus:	2-s2.0-32344442820
РИНЦ:	13522864
Chemical Abstracts:	2006:162661
Chemical Abstracts (print):	144:391468
OpenAlex:	W2002620371

БД	Цитирований
Web of science	43
Scopus	46
РИНЦ	45
OpenAlex	49