Nanoscale Conjugated Ladder Polymers

我们将合成，表征和研究纳米级共轭梯形聚合物的性质，其具有基于多环杂芳族化合物的梯级和基于亚芳基-亚乙炔基-丁二炔基的两条或三条链（称为“侧轨”或“腿”），以及它们各自定义的线性低聚物。这些化合物将配备有柔性侧链，以确保其溶液加工性。梯形结构预期是相当刚性的，并且应该表现出有趣的光学性质。它们将通过含有另外两个受保护的末端乙炔的双乙炔的均聚（双乙炔偶联）来制备。在第一链的形成和封端之后，剩余的乙炔的脱保护允许分子内拉链反应以形成梯形结构，其然后用第二封端反应完成。梯形的多环杂芳族“梯级”一方面保证聚合物的刚性，另一方面梯级可通过可靠的胺-酮缩合容易地接近。我们将研究两种不同的多环杂芳族梯级，分别导致12 <$（使用二喹喔啉芘）和7 <$（使用菲嗪）的梯形链之间的距离。聚合物是封端的，因此它们不含游离的炔属基团。端盖可以广泛变化。我们还将研究新的梯形端帽，允许分子内的第二封端。这将克服对拉链反应的敏感优化的需要，这是迄今为止获得尽可能无缺陷的结构所必需的。我们将准备两股和三股的梯子，预计会更硬。对于所有系列的化合物，我们将合成，表征（NMR，MS，UV/维斯）和研究（荧光，STM与S. S. Jester（UNiv. Bonn））的聚合物以及限定的低聚物。我们将与格里姆教授（波恩大学）和Horinek教授（里根斯堡大学）合作进行详细的光谱实验（在本体和单分子水平上）以及分子动力学模拟，这将使我们能够获得关于分子结构，构象和光学性质的结构-性质关系的清晰图像。

We will synthesize, characterize and investigate the properties of nanoscale conjugated ladder polymers with rungs based on polycyclic heteroaromatics and two or three strands (termed “side rails” or “legs”) based on arylene-ethynylene-butadiynylenes, and their respective defined linear oligomers. The compounds will be equipped with flexible side chains to guarantee their solution processability. The ladder structures are expected to be rather rigid and should exhibit interesting optical properties. They will be made by homo-polymerization of bisacetylenes (Glaser-coupling) that contain additionally two protected terminal acetylenes. After formation and end-capping of the first strand, deprotection of the remaining acetylenes allows an intramolecular zipping reaction to form the ladder structure, which is then finalized with a second end-capping reaction. The polycyclic heteroaromatic “rungs” of the ladder guarantee on the one hand the stiffness of the polymer and on the other hand, the rungs are readily accessible by a reliable amine-ketone condensation. We will investigate two different polycyclic heteroaromatic rungs that lead to distances between the ladder strands of 12 Å (using diquinoxal pyrene) and 7 Å (using phenanthrazine), respectively. The polymers are end-capped so that they do not contain free acetylenic groups. The endcap can be varied widely. We will also investigate new ladder-type endcaps that allow an intramolecular second end-capping. This will overcome the need for sensitive optimization of the zipping reaction which was necessary so far to obtain structures as free of defects as possible. We will prepare ladders with two strands and also with three strands, which are expected to be even stiffer. For all series of compounds, we will synthesize, characterize (NMR, MS, UV/Vis) and investigate (fluorescence, STM in collaboration with Dr. S.-S. Jester (UNiv. Bonn)) the polymers as well as defined oligomers. We will carry out detailed spectroscopic experiments (on the bulk and single-molecule level) as well as molecular dynamic simulations in collaboration with Prof. Grimme (Univ. Bonn) and Prof. Horinek (Univ. Regensburg) which will allow us to obtain a clear picture of the structure-property relationships with respect to the molecules’ structural, conformational and optical properties.