Molecular Structure of a Hydridoniobocene Complex [Nb(η5-C5H4SiMe3)2(H)3] and Its Use as Catalyst for the Ring-Opening Polymerization of Cyclic Esters
Molecular Structure of a Hydridoniobocene Complex [Nb(η5-C5H4SiMe3)2(H)3] and Its Use as Catalyst for the Ring-Opening Polymerization of Cyclic Esters
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DOI：
10.1002/ejic.201101263
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发表时间：
2012-03-01
影响因子：
2.3
通讯作者：
Tercero-Morales, Maria T.
中科院分区：
文献类型：
--
作者：
Alonso-Moreno, Carlos;Antinolo, Antonio;Tercero-Morales, Maria T.
本文报道了用x射线衍射表征的第二种多羟基二茂物。根据H-H距离和H-Nb-H角，将[Nb(eta(5)-C5H4SiMe3)(2)(H)(3)](1)归类为“压缩氢化物”。化合物1是一种高效的单组分引发剂，用于开环聚合-己内酯和-戊内酯。epsilon-己内酯和delta-戊内酯都能在几个小时内聚合，得到高到中等分子量的聚合物，具有中等到广泛的多分散性。聚合物端基分析表明，聚合反应是通过氧原子与酰基碳原子之间的环解理发生的配位插入机制进行的。
The second polyhydridoniobocene complex that was characterized by X-ray diffraction is reported. On the basis of H-H distances and H-Nb-H angles, [Nb(eta(5)-C5H4SiMe3)(2)(H)(3)] (1) is classified as a "compressed hydride". Compound 1 acts as an efficient single-component initiator for the ring-opening polymerization of epsilon-caprolactone and delta-valerolactone. epsilon-Caprolactone and delta-valerolactone are both polymerized within a few hours to yield high-to-medium-molecular-weight polymers with medium to broad polydispersities. Polymer end-group analysis showed that the polymerization proceeds through a coordination-insertion mechanism based on the cleavage of the ring between the oxygen atom and the acyl carbon atom.