Self-assembly of dendritic tris(crown ether) hexagons and their complexation with dibenzylammonium cations.
Self-assembly of dendritic tris(crown ether) hexagons and their complexation with dibenzylammonium cations.
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DOI：
10.1021/jo101648p
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发表时间：
2010-09
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通讯作者：
Xingdong Xu;Hai‐Bo Yang;Yao-Rong Zheng;Koushik Ghosh;Matthew M. Lyndon;D. Muddiman;P. Stang
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文献类型：
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作者：
Xingdong Xu;Hai‐Bo Yang;Yao-Rong Zheng;Koushik Ghosh;Matthew M. Lyndon;D. Muddiman;P. Stang
通过配位驱动的自组装，构建了一系列新的树枝状三（冠醚）六边形。将120°含冠醚的二铂（II）受体与120°树枝状联吡啶供体以1：1的比例组合允许以定量产率形成具有六边形空腔的树枝状三冠醚衍生物的新家族。这些侧基的数量和位置可以在六方金属配合物上精确控制。所有树枝状多冠醚六配体的结构均经多核NMR（（1）H和（31）P）、ESI-MS和ESI-TOF-MS以及元素分析确证。这些树枝状三价受体与二苄基铵阳离子的络合作用通过（1）H NMR滴定实验进行了研究。基于1H NMR滴定实验，采用非线性最小二乘法拟合得到了受体与客体的热力学结合常数。结果表明，随着[G 0]到[G3]树枝化基元生成数的增加，各组装体的缔合常数相应减小，这可能是由于树枝化基元对主客体络合作用的空间位阻效应所致.
The construction of a new series of dendritic tris(crown ether) hexagons via coordination-driven self-assembly is described. Combining 120° crown ether-containing diplatinum(II) acceptors with 120° dendritic dipyridyl donors in a 1:1 ratio allows for the formation of a new family of dendritic triple crown ether derivatives with a hexagonal cavity in quantitative yields. The number and the position of these pendant groups can be precisely controlled on the hexagonal metallacycle. The structures of all dendritic multiple crown ether hexgaons are confirmed by multinuclear NMR ((1)H and (31)P), ESI-MS and ESI-TOF-MS, and elemental analysis. The complexation of these dendritic trivalent receptors with dibenzylammonium cations was investigated by (1)H NMR titration experiments. The thermodynamic binding constants between the receptors and guests were established by using the nonlinear least-squares fit method based on (1)H NMR titration experiments. It was found that the association constants of each assembly decrease correspondingly upon the increase of the generation of the dendrons from [G0] to [G3], which might be caused by the steric effect of the dendrons on host-guest complexation.