作者:Andrew L. Johnson、Matthew G. Davidson、Yolanda Pérez、Matthew D. Jones、Nicolas Merle、Paul R. Raithby、Stephen P. Richards
DOI:10.1039/b904534a
日期:——
Reaction of Al(OiPr)3 with the tris-phenol amine ligand L1H3 in toluene at ambient temperature results in the formation of the iso-propanol adduct [HOiPr·Al(L1)]. Single crystal X-ray diffraction analysis reveals the structure to be a hydrogen bonded dimer. Reaction of Al(OiPr)3 (or AlMe3) with L1H3 in THF affords the related, and structurally characterised THF adduct, [THF·Al(L1)]. Similar reaction of Al(OiPr)3 (or AlMe3) with the bis-phenol amine and tetra-phenol diamine ligands, L2H3 and L3H4, results in the formation and isolation of the complexes [Al(L2)]2 and [Al(L3)H] respectively, both of which have been structurally characterised viasingle crystal X-ray diffraction studies. Reaction of the alkoxide bridged dimer [Al(L2)]2 with the strong Lewis base HMPA results in the formation of the monomeric HMPA adduct [HMPA·Al(L2)] which was also structurally characterised. The adduct [HOiPr·Al(L1)] and the dimer [Al(L2)]2 were tested for their activity in the ring-opening polymerisation (ROP) of rac-lactide under solvent-free conditions (130 °C). Under the conditions employed [Al(L2)]2 failed to produce polymer after 48 h, in stark contrast to [HOiPr·Al(L1)] which after 24 h and 48 h produced narrow molecular weight polymer (24 h: yield = 25%, Mn = 14500 and PDI = 1.05; 48 h: yield = 65%, Mn = 47700 and PDI = 1.06).
在环境温度下,Al(OiPr)3 与三苯酚胺配体 L1H3 在甲苯中反应,生成异丙醇加合物 [HOiPr-Al(L1)]。单晶 X 射线衍射分析表明其结构为氢键二聚体。Al(OiPr)3 (或 AlMe3)与 L1H3 在 THF 中反应,可得到相关的、结构表征为 THF 的加合物 [THF-Al(L1)]。Al(OiPr)3(或 AlMe3)与双酚胺和四酚二胺配体 L2H3 和 L3H4 发生类似反应,分别形成并分离出[Al(L2)]2 和[Al(L3)H]复合物。烷氧基桥接二聚体 [Al(L2)]2 与强路易斯碱 HMPA 反应,形成单体 HMPA 加合物 [HMPA-Al(L2)],并对其进行了结构表征。测试了加合物 [HOiPr-Al(L1)] 和二聚体 [Al(L2)]2 在无溶剂条件(130 °C)下对 rac-内酰胺开环聚合(ROP)的活性。在所采用的条件下,[Al(L2)]2 在 48 小时后未能生成聚合物,这与[HOiPr-Al(L1)]形成了鲜明对比,后者在 24 小时和 48 小时后生成了窄分子量聚合物(24 小时:产率 = 25%,Mn = 14500,PDI = 1.05;48 小时:产率 = 65%,Mn = 47700,PDI = 1.06)。