Department of Chemistry and Chemical Biology, Graduate School of Engineering, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan.
J Org Chem. 2012 Sep 7;77(17):7595-606. doi: 10.1021/jo301458m. Epub 2012 Aug 21.
We report the syntheses, structures, photophysical properties, and redox characteristics of donor-acceptor-fused π-systems, namely π-extended thiadiazoles 1-5 fused with thienopyrrole or indole moieties. They were synthesized by the Stille coupling reactions followed by the PPh(3)-mediated reductive cyclizations as key steps. X-Ray crystallographic studies showed that isomeric 1b and 2b form significantly different packing from each other, and 1a and 4a afford supramolecular networks via multiple hydrogen bonding with water molecules. Thienopyrrole-fused compounds 1b and 2b displayed bathochromically shifted intramolecular charge-transfer (CT) bands and low oxidation potentials as compared to indole-fused analog 3b and showed moderate to good fluorescence quantum yields (Φ(f)) up to 0.73. In 3b-5b, the introduction of electron-donating substituents in the indole moieties substantially shifts the intramolecular CT absorption maxima bathochromically and leads to the elevation of the HOMO levels. The Φ(f) values of 3-5 (0.04-0.50) were found to be significantly dependent on the substituents in the indole moieties. The OFET properties with 1b and 2b as an active layer were also disclosed.
我们报告了供体-受体融合π-体系的合成、结构、光物理性质和氧化还原特性，即噻二唑 1-5 与噻吩并吡咯或吲哚部分融合的π-扩展体系。它们是通过 Stille 偶联反应以及关键步骤的 PPh(3)介导的还原环化反应合成的。X 射线晶体学研究表明，异构体 1b 和 2b 形成了明显不同的堆积，1a 和 4a 通过与水分子的多重氢键形成超分子网络。与吲哚融合的类似物 3b 相比，噻吩并吡咯融合的化合物 1b 和 2b 显示出红移的分子内电荷转移（CT）带和较低的氧化电位，并表现出从中等到良好的荧光量子产率（Φ(f)），高达 0.73。在 3b-5b 中，吲哚部分中供电子取代基的引入会使分子内 CT 吸收最大值显著红移，并导致 HOMO 水平升高。3-5（0.04-0.50）的 Φ(f) 值被发现与吲哚部分的取代基显著相关。作为活性层的 1b 和 2b 的 OFET 性质也被揭示。
