Synthetic and Structural Investigations of Organomagnesium Complexes of Hybrid Boraamidinate/Amidinate Ligands and Their Use in the Polymerization of rac-Lactide
Synthetic and Structural Investigations of Organomagnesium Complexes of Hybrid Boraamidinate/Amidinate Ligands and Their Use in the Polymerization of rac-Lactide
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杂化硼脒/脒配体有机镁配合物的合成和结构研究及其在外消旋丙交酯聚合中的应用
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发表时间：
2005
期刊：
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通讯作者：
M. Parvez
中科院分区：
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作者：
T. Chivers;C. Fedorchuk;M. Parvez
研究了 protio 和锂 bamam 配合物 (H)bamam-1 和 (Li)bamam-1 [bamam-1 = {DippN(Ph)B(NtBu)CnBu(NtBu)}, Dipp = 2,6-二异丙基苯基]与镁的络合化学。重点放在溶剂化和非溶剂化芳基/烷基镁 bamam 配合物 (RMgL)bamam-1 的制备和表征上（1，R = tBu，L = 无；2，R = Mes，L = 无；3，R = Me，L = OEt2；4，R = Ph，L = THF；5，R = iPr，L = THF；6，R = nBu，L = OEt2)。 X 射线结构分析表明，Mg bamam-1 配合物是六元环，由于跨环 Mg−N 相互作用 (2.39−2.85 A)，其采用扭曲的船形结构。变温核磁共振谱表明这种相互作用在溶液中得以维持。外消旋丙交酯与配合物 3−6 聚合的初步研究表明，配合物 3 和 4 促进聚合过程产生杂偏聚丙交酯，而配合物 5 和 6 则无活性。
The complexation chemistry of the protio and lithium bamam complexes (H)bamam-1 and (Li)bamam-1 [bamam-1 = {DippN(Ph)B(NtBu)CnBu(NtBu)}, Dipp = 2,6-diisopropylphenyl] with magnesium is explored. Emphasis is placed on the preparation and characterization of both solvated and unsolvated aryl/alkylmagnesium bamam complexes (RMgL)bamam-1 (1, R = tBu, L = none; 2, R = Mes, L = none; 3, R = Me, L = OEt2; 4, R = Ph, L = THF; 5, R = iPr, L = THF; 6, R = nBu, L = OEt2). X-ray structural analyses reveal that the Mg bamam-1 complexes are six-membered rings, which adopt a distorted boat structure as a result of a transannular Mg−N interaction (2.39−2.85 A). Variable-temperature NMR spectra indicate this interaction is maintained in solution. Preliminary studies of the polymerization of rac-lactide with complexes 3−6 revealed that 3 and 4 promote the polymerization process producing hetero-biased polylactide, whereas 5 and 6 are inactive.