Synthesis and Structure of Homo- and Heterometallic Lithium-Magnesium Complexes and Their Reactivity in the ROP of rac-Lactide
Synthesis and Structure of Homo- and Heterometallic Lithium-Magnesium Complexes and Their Reactivity in the ROP of rac-Lactide
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DOI：
10.1021/om400940f
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发表时间：
2013-11-11
期刊：
影响因子：
2.8
通讯作者：
Cano, Jesus
中科院分区：
文献类型：
--
作者：
Gallegos, Carlos;Tabernero, Vanessa;Cano, Jesus
合成了锂[Li-2{(ETA(2)-O(C10H6)N=N(C6H5)}(2)](N)和镁[Mg{(ETA(2)-O(C10H6)N=N(C6H5)}(2)](N))同金属偶氮配合物[Li2Mg2{(ETA(2)-O(C10H6)N=N(C6H5)}(6)]。异金属络合物表现出一种新的结构，描述为两个截断的立方体，作为立方体的一侧共享一个Mg2O2环。研究了这些络合物在RAC-丙交酯聚合中的应用。为了深入了解这些化合物作为催化剂的行为，使用了H-1核磁共振实验、扩散有序光谱和X射线研究。DOSY核磁共振实验支持混合金属配合物3的结构在苯溶液中保持不变的观点，H-1核磁共振研究表明它遵循活化单体机理。
The homometallic azo complexes of lithium [Li-2{(eta(2)-O(C10H6)N=N(C6H5)}(2)](n) and magnesium [Mg{(eta(2)-O(C10H6)N=N(C6H5)}(2)](n) and the heterometallic lithium-magnesium derivative [Li2Mg2{(eta(2)-O(C10H6)N=N(C6H5)}(6)] have been synthesized. The heterometallic complex exhibits a novel structure described as two truncated cubes that share a Mg2O2 ring as one of the cube sides. These complexes have been studied in the polymerization of rac-lactide. In order to gain insight into the behavior of these compounds as catalysts, H-1 NMR experiments, diffusion-ordered spectroscopy, and X-ray studies have been used. DOSY NMR experiments support the notion that the structure of the mixed-metal complex 3 persists in benzene solution, and H-1 NMR studies show that it follows an activated monomer mechanism.