Ring-Opening Polymerization Behavior of ansa- and Spirocyclic ansa-Zirconocene Complexes
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- 作者：Timothy J. Peckham ; Paul Nguyen ; Sara C. Bourke ; Qinyan Wang ; Daryll G. Harrison ; Peter Zoricak ; Charles Russell ; Louise M. Liable-Sands ; Arnold L. Rheingold ; Alan J. Lough ; and Ian Manners
- 刊名：Organometallics
- 出版年：2001
- 出版时间：July 9, 2001
- 年：2001
- 卷：20
- 期：14
- 页码：3035 - 3043
- 全文大小：158K
- 年卷期：v.20,no.14(July 9, 2001)
- ISSN：1520-6041
文摘
Attempts to develop a ring-opening polymerization (ROP) approach to polymeric zirconocene complexes are reported. A new silicon-bridged [1][1]zirconocenophane, (SiMe2)2(
5-C5H3)2Zr(NEt2)2 (3a), was synthesized by reaction of Zr(NEt2)4 with (C5H4)2(SiMe2)2 (4).Single-crystal X-ray diffraction revealed a highly tilted structure with an angle of 73.1(4)
,a significant increase over the untethered compound (5-MeC5H4)2ZrCl2 (2), which possessesa tilt angle of 54.2. This and the related compounds (SiMe2)(5-C5H4)2MCl2 (1a, M = Ti;1b, M = Zr) and (SiMe2)2(5-C5H3)2ZrCl2 (3b) were tested for transition-metal catalyzed ROPbehavior in the presence of Pt(0) catalysts but were found to be inactive. The novel spirocyclicsilacyclobutane-bridged monomer (CH2)3Si(5-C5H4)2ZrCl2 (7b) was prepared via a "fly trap"amine elimination reaction between cyclotrimethylenedicyclopentadienylsilane (8) andZr(NMe2)4; this initially yielded (CH2)3Si(5-C5H4)2Zr(NMe2)2 (7a), which was converted to7b by reaction with a slight excess of Me3SiCl. 7a and 7b were characterized by 29Si, 13C,and 1H NMR spectroscopy and mass spectrometry as well as single-crystal X-ray diffraction.Both showed moderate tilt angles (61.7(2) and 59.69(7), respectively) as well as highlystrained silacyclobutane rings with C-Si-C bond angles of 79.7(2) and 80.64(10),respectively. Transition-metal-catalyzed ROP of 7b led to the formation of the polycarbosilane[(CH2)3Si(5-C5H4)2ZrCl2]n (10). Both the soluble and insoluble fractions of 10 were characterized by CP-MAS 29Si and 13C NMR, and the soluble, oligomeric fraction was furthercharacterized by solution 29Si, 13C, and 1H NMR. Complexes 7a, 7b, and polyzirconocene 10were found to exhibit moderate activity as ethylene polymerization catalysts.
5-C5H3)2Zr(NEt2)2 (3a), was synthesized by reaction of Zr(NEt2)4 with (C5H4)2(SiMe2)2 (4).Single-crystal X-ray diffraction revealed a highly tilted structure with an angle of 73.1(4),a significant increase over the untethered compound (5-MeC5H4)2ZrCl2 (2), which possessesa tilt angle of 54.2. This and the related compounds (SiMe2)(5-C5H4)2MCl2 (1a, M = Ti;1b, M = Zr) and (SiMe2)2(5-C5H3)2ZrCl2 (3b) were tested for transition-metal catalyzed ROPbehavior in the presence of Pt(0) catalysts but were found to be inactive. The novel spirocyclicsilacyclobutane-bridged monomer (CH2)3Si(5-C5H4)2ZrCl2 (7b) was prepared via a "fly trap"amine elimination reaction between cyclotrimethylenedicyclopentadienylsilane (8) andZr(NMe2)4; this initially yielded (CH2)3Si(5-C5H4)2Zr(NMe2)2 (7a), which was converted to7b by reaction with a slight excess of Me3SiCl. 7a and 7b were characterized by 29Si, 13C,and 1H NMR spectroscopy and mass spectrometry as well as single-crystal X-ray diffraction.Both showed moderate tilt angles (61.7(2) and 59.69(7), respectively) as well as highlystrained silacyclobutane rings with C-Si-C bond angles of 79.7(2) and 80.64(10),respectively. Transition-metal-catalyzed ROP of 7b led to the formation of the polycarbosilane[(CH2)3Si(5-C5H4)2ZrCl2]n (10). Both the soluble and insoluble fractions of 10 were characterized by CP-MAS 29Si and 13C NMR, and the soluble, oligomeric fraction was furthercharacterized by solution 29Si, 13C, and 1H NMR. Complexes 7a, 7b, and polyzirconocene 10were found to exhibit moderate activity as ethylene polymerization catalysts.