Increasing the diameter of cylindrical and spherical supramolecular dendrimers by decreasing the solid angle of their monodendrons via periphery functionalization
Increasing the diameter of cylindrical and spherical supramolecular dendrimers by decreasing the solid angle of their monodendrons via periphery functionalization
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DOI：
10.1021/ja0024643
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发表时间：
2000-10-25
影响因子：
15
通讯作者：
Ungar, G
中科院分区：
文献类型：
--
作者：
Percec, V;Cho, WD;Ungar, G
基于内部AB(3) 3,4,5-三取代苯甲醚重复单元的三代自组装单树的合成，其中AB(2) 3,4-双[p-(n-十二烷-1-基氧基)苯甲氧基]苯甲醚单树[(4-3,4)12G1-X]附着在外围，并通过X射线衍射对相应的超分子树枝状聚合物进行结构分析(XRD) 实验进行了描述。这些实验的结果与我们实验室之前报道的三代单树的数据进行了比较，该三代单树基于相同的内部AB(3)重复单元，外围含有AB(3) 3,4,5-三[p-(n-十二烷-1-基氧基)苯甲氧基]苯甲基醚单树[(4-3,4,5)12G1-X]（Percec，V.；Cho，W.-D.；Mosier， P.E.；Yardley，D.J.P.J.Soc.1998，120，11061。在这两个系列的单树中，单树的立体角都随着世代数的增加而增加。结果，圆柱形和球形超分子树枝状聚合物的直径增加小于完全延伸的单树枝状重复单元所预期的直径增加。对于相同的内部重复单元，单枝体的立体角由附着在其外围的单元的立体角决定。与在其外围含有(4-3,4,5)12G1-X AB(3)基团的系列相比，连接到单树枝外围的(4-3,4)12G1-X AB2基团减小了它们的立体角，随后，AB(2)基团增加了超分子树枝状聚合物的直径。这种结构效应的阐明澄清了当前的一些局限性，并为从树突构建块设计功能纳米系统提供了新策略。
The synthesis of three generations of self-assembling monodendrons based on an internal AB(3) 3,4,5-trisubstituted benzyl ether repeat unit containing an AB(2) 3,4-bis[p-(n-dodecan-1-yloxy)benzyloxyl]benzyl ether monodendron [(4-3,4)12G1-X] attached on the periphery and the structural analysis of the corresponding supramolecular dendrimers by X-ray diffraction (XRD) experiments are described. The results from these experiments are compared with data reported previously from our laboratory on three generations of monodendrons based on the same internal AB(3) repeat unit containing an AB(3) 3,4,5-tris[p-(n-dodecan-1-yloxy)benzyloxy]benzyl ether monodendron [(4-3,4,5)12G1-X] on the periphery (Percec, V.; Cho, W.-D.; Mosier, P. E.; Ungar, G.; Yeardley, D. J. P. J. Am. Chem. Soc. 1998, 120, 11061). In both series of monodendrons, the solid angle of the monodendron increases with the increase of the generation number. As a result, the increase in the diameter of the cylindrical and spherical supramolecular dendrimers is smaller than the one expected from the fully extended monodendritic repeat unit. For the same internal repeat unit, the solid angle of the monodendron is determined by the solid angle of the unit attached to its periphery. The (4-3,4)12G1-X AB2 group attached to the periphery of the monodendrons decreases their solid angle by comparison with the series containing the (4-3,4,5)12G1-X AB(3) group on their periphery, and subsequently, the AB(2) group increases the diameter of the supramolecular dendrimers. The elucidation of this architectural effect clarifies some of the current limitations and provides new strategies for the design of functional nanosystems from dendritic building blocks.