期刊
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
卷 135, 期 50, 页码 18738-18741出版社
AMER CHEMICAL SOC
DOI: 10.1021/ja409843v
关键词
-
资金
- NSF [DMR-1001903, CHE-1306730]
- Division Of Chemistry
- Direct For Mathematical & Physical Scien [1306730] Funding Source: National Science Foundation
The zwitterionic ring-opening of 2,2,5,5-tetramethyl-2,5-disila-1-oxacyclopentane (TMOSC) with N-heterocyclic carbenes generates high molecular weight cyclic p(TMOSC). The NHC-mediated polymerization of TMOSC with 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene (IMes, 1) generates the poly(carbosiloxane) p(TMOSC) with molecular weights from 27 000 < M-n < 80 000 Da (1.4 < M-w/M-n < 2.2) within 30 mm at room temp. With the more nucleophilic carbene 1,3,4,5-tetramethyl-imidazol-2-ylidene (4), the ring-opening polymerization occurs within minutes at room temperature to generate cyclic p(TMOSC) with molecular weights up to M-n = 940 000 Da (M-w/M-n = 3.2). The resulting p(TMOSC)s are predominantly cyclic as evidenced by dilute solution viscosity studies and MALDI-TOF MS. DFT calculations provide support for both zwitterionic and neutral, cyclic intermediates.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据