Maltar-Strmečki Nadica, Yu Hao, Messmer Daniel, Zhang Baozhong, Schlüter A Dieter, Hinderberger Dariush
Martin-Luther-Universität Halle-Wittenberg, Institut für Chemie, Von-Danckelmann-Platz 4, 06120, Halle, Germany.
Ruđer Bošković Institute, Division of Physical Chemistry, Laboratory for Magnetic Resonance, Bijenička 54, 10000, Zagreb, Croatia.
Chemphyschem. 2016 Sep 5;17(17):2767-72. doi: 10.1002/cphc.201600580. Epub 2016 Jul 6.
Aspects of size, structural (im)perfection, inner density, and guest molecule loading capacity of dendronized polymers (DPs) of high generation (6≤g≤8) in aqueous solution are studied using electron paramagnetic resonance spectroscopy on amphiphilic, spin-labeled guest molecules. The results show that the interior of the charged DPs is strongly polar, especially in comparison to their lower generation (1-4) analogues. This is a direct sign that large amounts of water penetrate the DP surface, reflecting the structural (im)perfections of these high-generation DPs and much lower segmental densities than theoretically achievable. Images obtained with atomic force microscopy reveal that the high-generation DPs do not aggregate and give further insights into the structural imperfections. Electron paramagnetic resonance spectroscopic data further show that despite their structural imperfections, these DPs can bind and release large numbers of amphiphilic molecules. It is concluded that attention should be paid to their synthesis, for which a protocol needs to be developed that avoids the relatively large amount of defects generated in the direct conversion of a generation g=4 DP to a generation g=6 DP, which had to be used here.
使用电子顺磁共振光谱对两亲性、自旋标记的客体分子进行研究，以探究高代数（6≤g≤8）树枝状聚合物（DPs）在水溶液中的尺寸、结构（不）完美性、内部密度和客体分子负载能力等方面。结果表明，带电DPs的内部具有很强的极性，特别是与低代数（1-4）类似物相比。这直接表明大量的水渗透到DPs表面，反映了这些高代数DPs的结构（不）完美性以及远低于理论可实现值的链段密度。原子力显微镜获得的图像显示高代数DPs不会聚集，并进一步揭示了结构上的不完美之处。电子顺磁共振光谱数据还表明，尽管这些DPs存在结构缺陷，但它们仍能结合并释放大量两亲性分子。得出的结论是，应关注它们的合成，为此需要开发一种方案，以避免在将g = 4的DP直接转化为g = 6的DP（此处必须使用）过程中产生相对大量的缺陷。
