Yttrium Phosphasalen Initiators for rac-Lactide Polymerization: Excellent Rates and High Iso-Selectivities
Yttrium Phosphasalen Initiators for rac-Lactide Polymerization: Excellent Rates and High Iso-Selectivities
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DOI：
10.1021/ja310003v
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发表时间：
2012-12-26
影响因子：
15
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.
报道了立体控制开环聚合的高活性磷酸体钇引发剂。引发剂由一类新的辅助配体协调：一种常见的“salen”配体的亚磷磷烷衍生物，称为“phosphasalen”。改变磷脂体结构可以获得高的等选择性（P-i = 0.84）或异选择性（P-s = 0.87）。引发剂也表现出非常高的速率，优异的聚合控制，以及对低负荷的耐受性；此外，立体控制不需要手性助剂/配体。如此高的比率与高的等选择性的结合是非常不寻常的。
Highly active yttrium phosphasalen initiators for the stereocontrolled ring-opening polymerization of rac-lactide are reported. The initiators are coordinated by a new class of ancillary ligand: an iminophosphorane derivative of the popular "salen" ligand, termed "phosphasalen". Changing the phosphasalen structure enables access to high iso-selectivities (P-i = 0.84) or hetero-selectivities (P-s = 0.87). The initiators also show very high rates, excellent polymerization control, and tolerance to low loadings; furthermore, no chiral auxiliaries/ligands are needed for the stereocontrol. The combination of such high rates with high iso-selectivities is very unusual.