Free-Standing, Single-Monomer-Thick Two-Dimensional Polymers through Covalent Self-Assembly in Solution
Free-Standing, Single-Monomer-Thick Two-Dimensional Polymers through Covalent Self-Assembly in Solution
复制标题
DOI：
10.1021/ja4002019
复制
发表时间：
2013-05-01
影响因子：
15
通讯作者：
Kim, Kimoon
中科院分区：
文献类型：
--
作者：
Baek, Kangkyun;Yun, Gyeongwon;Kim, Kimoon
二维（2D）聚合物的设计和合成是一项具有挑战性的任务，迄今为止仅通过固体表面“模板”或在2D受限空间中预组织构建块的帮助在溶液中实现。我们提出了一种新的方法，用于合成独立的，共价键合的，单单体厚的二维聚合物在溶液中没有任何预组织的固体表面或界面上的构建块，通过采用形状导向的共价自组装刚性，盘形的构建块具有横向预先设置的反应基团在其周边。我们通过（烯丙氧基）（1,2）CB[6]（具有1,2个横向倾向的反应性烯烃基团的葫芦[6]脲（CB[6]）衍生物）与1，2-乙二硫醇之间的硫醇-烯“点击”反应来证明我们的策略，以合成稳健且易于转移的2D聚合物。我们可以利用完全质子化的精胺（两端带正电荷）对CB的高结合亲和力[6]，在合成过程中通过静电排斥使每个单独的聚合物片层彼此分离，从而首次获得溶液中单一单体厚度的2D聚合物。CB[6]重复单元在所得2D聚合物中的排列已使用金纳米颗粒标记和扫描透射电子显微镜表征。此外，我们已经通过将其应用于不同的单体以生成2D聚合物来证实了我们的合成方法的通用性。新型2D聚合物，如我们的CB[6]衍生聚合物，可用于选择性转运，受控药物递送和化学传感，甚至可用作有序功能化的明确2D支架和自下而上3D构建的平台。
The design and synthesis of two-dimensional (2D) polymers is a challenging task, hitherto achieved in solution only through the aid of a solid surface "template" or preorganization of the building blocks in a 2D confined space. We present a novel approach for synthesizing free-standing, covalently bonded, single-monomer-thick 2D polymers in solution without any preorganization of building blocks on solid surfaces or interfaces by employing shape-directed covalent self-assembly of rigid, disk-shaped building blocks having laterally predisposed reactive groups on their periphery. We demonstrate our strategy through a thiol-ene "click" reaction between (allyloxy)(12)CB[6], a cucurbit[6]uril (CB[6]) derivative with 12 laterally predisposed reactive alkene groups, and 1,2-ethanedithiol to synthesize a robust and readily transferable 2D polymer. We can take advantage of the high binding affinity of fully protonated spermine (positive charges on both ends) to CB[6] to keep each individual polymer sheet separated from one another by electrostatic repulsion during synthesis, obtaining, for the first-time ever, a single-monomer-thick 2D polymer in solution. The arrangement of CB[6] repeating units in the resulting 2D polymer has been characterized using gold nanoparticle labeling and scanning transmission electron microscopy. Furthermore, we have confirmed the generality of our synthetic approach by applying it to different monomers to generate 2D polymers. Novel 2D polymers, such as our CB[6] derived polymer, may be useful in selective transport, controlled drug delivery, and chemical sensing and may even serve as well-defined 2D scaffolds for ordered functionalization and platforms for bottom-up 3D construction.