Molecular Parameters Including Fluorination Program Order During Hierarchical Helical Self-Organization of Self-Assembling Dendrons
Molecular Parameters Including Fluorination Program Order During Hierarchical Helical Self-Organization of Self-Assembling Dendrons
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DOI：
10.1016/j.giant.2022.100103
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发表时间：
2022-05
期刊：
影响因子：
7
通讯作者：
M. Peterca;M. R. Imam;Andrés E Dulcey;K. Morimitsu;Qi Xiao;Devendra S. Maurya;V. Percec
中科院分区：
文献类型：
--
作者：
M. Peterca;M. R. Imam;Andrés E Dulcey;K. Morimitsu;Qi Xiao;Devendra S. Maurya;V. Percec
一级结构赋予三级结构，三级结构决定功能。这一基本原理是负责产生高阶和精确的功能，在生物组件，包括巨型和巨型蛋白质和核酸，以及在金属产生的只有几个原子。然而，这种产生高阶和非常精确的功能的不依赖于尺寸的能力在非生物组件中还无法获得，这些组件使用相同的原则进行分层自组织。本文研究了分子参数对由直链或支链氢化或直链半氟化烷基（4- 3，4 - 3，5）-X自组装生成的螺旋柱状组装体的分级自组织的作用，顶点为-CO_2CH_3或-CH_2OH。在这些结构分析实验中，采用了差示扫描量热法、小角度和广角粉末和取向纤维X射线衍射实验以及螺旋衍射理论、2-D和3-D电子密度图的组合。他们证明，与基于在其顶点含有酯基的树枝状分子的超分子螺旋柱的顺序相比，在自组装树枝状分子的顶点处的H-键合增强了螺旋柱的顺序。这是在自组装树枝化基元的外围的直链和支链烷基的情况。出乎意料的是，自组装树枝状分子含有半氟化烷基在其周边和H-键合基团在其顶点增加甚至更多的顺序，其超分子全氟化多孔螺旋柱。在所有情况下，螺旋介导的芳香部分的树突，但层次影响的顶点和外围组。支链烷基与H-键在顶点处的组合产生了一种新的机制，以将由形成柱的（4- 3，4 - 3，5）-X自组装树枝化物组装的螺旋柱转化为由锥形树枝化物构象异构体组织的球形组装体，形成A15 Frank-Kasper相。
Primary structure endows tertiary structure while tertiary structure determines function. This fundamental principle is responsible for the generation of high order and precise functions in both biological assemblies including giant and mega proteins and nucleic acids as well as in metals generated from only few atoms. However, this size-independent ability to generate high order and very precise functions is not yet accessible in non-biological assemblies that use the same principles for their hierarchical self-organization. Here we report a study investigating the role of the molecular parameters on the hierarchical self-organizations of helical columnar assemblies produced from the column-forming self-assembling dendron (4-3,4-3,5)-X with a linear or branched hydrogenated or linear semifluorinated alkyl groups while apex is -CO2CH3or -CH2OH. A combination of differential scanning calorimetry, small and wide-angle powder and oriented fiber X-ray diffraction experiments together with helical diffraction theory, 2-D and 3-D electron density maps were employed in these structural analysis experiments. They demonstrated that H-bonding at the apex of the self-assembling dendron enhanced the order of the helical columns by comparison with the order of supramolecular helical columns based on dendrons containing an ester group at their apex. This was the case for both linear and branched alkyl groups at the periphery of the self-assembling dendron. Unexpectedly, self-assembling dendrons containing semifluorinated alkyl groups on their periphery and H-bonding groups at their apex increase even more the order of their supramolecular perfluorinated porous helical column. In all cases helix is mediated by the aromatic part of the dendron but hierarchically influenced both by the apex and peripheral groups. A combination of branched alkyl groups with H-bonding at the apex produced a new mechanism to transform helical columns assembled from the column-forming (4-3,4-3,5)-X self-assembling dendron into spherical assemblies, organized from conical dendron conformers, forming an A15 Frank-Kasper phase.