一系列的2-R-6-(芳基恶唑-/咪唑-2-基)吡啶和2,4-二叔丁基-6-(1H-菲并[9,10-d]咪唑-/恶唑-2合成并使用元素分析和光谱分析以及单晶X射线衍射分析对(yl)苯酚衍生物进行了表征。恶唑衍生物显示出比其咪唑类似物更高的光致发光效率。2-(菲[9,10-d]恶唑/咪唑-2-基)吡啶衍生物在非极性溶剂中的量子产率接近于1,但在极性溶剂中被淬灭。恶唑类似物在400nm和550nm区域之间产生可逆的荧光光开关,而咪唑类似物在极性溶剂中经历不可逆的光诱导的准分子形成。1个1 H NMR被用来合理化2-(菲并[9,10-d]咪唑-2-基)吡啶衍生物的准分子之间的分子间相互作用的建议模式。
Dialkylaluminium 2-imidazolylphenolates: Synthesis, characterization and ring-opening polymerization behavior towards lactides
作者:Wenjuan Zhang、Youhong Wang、Lin Wang、Carl Redshaw、Wen-Hua Sun
DOI:10.1016/j.jorganchem.2013.11.002
日期:2014.1
The stoichiometric reaction of the 2-imidazolylphenols (L1-L9) with the trialkylaluminium reagents AlR3 (R = Me, Et and iBu), afforded the corresponding dialkylaluminium 2-imidazolylphenolate complexes [R2Al(L1-L9)] (C1-C11), which were characterized by H-1/C-13 NMR spectroscopy and by elemental analysis. The molecular structures of the representative complexes C1, C2, C4, C6 and C11 were determined by single-crystal X-Ray diffraction, and revealed a distorted tetrahedral geometry at aluminum. These dialkylaluminium 2-imidazolylphenolates (C1-C11) could efficiently catalyze the ring-opening polymerization of lactides to afford high molecular weight polylactide, both in the presence and absence of BnOH, and as such represent rare examples of the use of bi-dentate ligation at aluminum in such lactide polymerization systems. On the basis of the polymerization results for L-lactide, D-lactide and rac-lactide, the nature of the ligands and the aluminum bound alkyls were found to significantly affect the catalytic activity as well as the properties of the resultant polylactides. (C) 2013 Elsevier B. V. All rights reserved.