Ramirez Y Medina Isabel-Maria, Rohdenburg Markus, Rusch Pascal, Duvinage Daniel, Bigall Nadja C, Staubitz Anne
Institute for Organic and Analytical Chemistry, University of Bremen Leobener Str. 7 28359 Bremen Germany
MAPEX Center for Materials and Processes, University of Bremen Bibliothekstr. 1 28359 Bremen Germany.
Mater Adv. 2021 Mar 27;2(10):3282-3293. doi: 10.1039/d1ma00104c.
The synthesis of four well-defined conjugated polymers containing unusual heterocycle units in the main chain, namely stannole units as building blocks, is reported. The stannole-thiophenyl copolymers were generated by tin-selective Stille coupling reactions in nearly quantitative yields of 94% to 98%. NMR data show that the tin atoms in the rings remain unaffected. Weight-average molecular weights ( ) were high (4900-10 900 Da and 9600-21 900 Da); and molecular weight distributions ( / ) were between 1.9 and 2.3. The new materials are strongly absorbing and appear blue-black to purple-black. All iodothiophenyl-stannole monomers and the resulting bisthiophenyl-stannole copolymers were investigated with respect to their optoelectronic properties. The absorption maxima of the polymers are strongly bathochromically shifted compared to their monomers by about 76 nm to 126 nm in chloroform. Density functional theory calculations support our experimental results of the single stannoles showing small HOMO-LUMO energy gaps of 3.17-3.24 eV. The optical band gaps of the polymers are much more decreased and were determined to be only 1.61-1.79 eV. Furthermore, both the molecular structures of stannoles and from single crystal X-ray analyses and the results of the geometry optimisation by DFT confirm the high planarity of the molecules backbone leading to efficient conjugation within the molecule.
本文报道了四种在主链中含有特殊杂环单元（即锡杂环戊二烯单元作为结构单元）的结构明确的共轭聚合物的合成。锡杂环戊二烯-噻吩基共聚物通过锡选择性的Stille偶联反应生成，产率接近定量，为94%至98%。核磁共振数据表明，环中的锡原子未受影响。重均分子量较高（4900 - 10900 Da和9600 - 21900 Da）；分子量分布（/）在1.9至2.3之间。这些新材料具有强烈的吸收性，呈现蓝黑色至紫黑色。对所有碘代噻吩基-锡杂环戊二烯单体和所得的双噻吩基-锡杂环戊二烯共聚物的光电性质进行了研究。与它们的单体相比，聚合物的吸收最大值在氯仿中发生了约76 nm至126 nm的强烈红移。密度泛函理论计算支持了我们对单个锡杂环戊二烯的实验结果，显示其HOMO-LUMO能隙较小，为3.17 - 3.24 eV。聚合物的光学带隙大幅降低，仅为1.61 - 1.79 eV。此外，通过单晶X射线分析得到的锡杂环戊二烯和的分子结构以及DFT几何优化结果均证实了分子骨架的高平面性，从而导致分子内的有效共轭。
