Yttrium Phosphasalen Initiators for rac-Lactide Polymerization
Yttrium Phosphasalen Initiators for rac-Lactide Polymerization
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DOI：
10.1021/om301129k
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发表时间：
2013-03-11
期刊：
影响因子：
2.8
通讯作者：
Williams, Charlotte K.
中科院分区：
文献类型：
--
作者：
Bakewell, Clare;Thi-Phuong-Anh Cao;Williams, Charlotte K.
报道了一系列高活性的外消旋丙交酯异相选择性开环聚合的钇磷杂环戊二烯引发剂。引发剂是钇醇盐络合物，由流行的“salen”配体的亚氨基膦类似物连接，称为“phosphasalens”。合成了一系列新颖的磷杂环戊二烯，其酚氧环上具有不同的取代基，并且亚乙基、亚丙基、外消旋亚环己基、R，R-亚环己基、亚苯基和2，2-二甲基亚丙基连接亚氨基膦部分。改变磷杂环戊二烯配体上的取代基导致聚合速率（k（obs））和PLA异规度（P-s = 0.87）的变化。通常，引发剂具有高速率、优异的聚合控制和对低负载的耐受性。
A series of highly active yttrium phosphasalen initiators for the heteroselective ring-opening polymerization of rac-lactide are reported. The initiators are yttrium alkoxide complexes ligated by iminophosphorane analogues of the popular "salen" ligand, termed "phosphasalens". A series of novel phosphasalens have been synthesized, with varying substituents on the phenoxide rings and ethylene, propylene, rac-cyclohexylene, R,R-cyclohexylene, phenylene, and 2,2-dimethylpropylene groups linking the iminophosphorane moieties. Changing the substituents on the phosphasalen ligands results in changes to the rates of polymerization (k(obs)) and to the PLA heterotacticity (P-s = 0.87). Generally, the initiators have high rates, excellent polymerization control, and a tolerance to low loadings.