Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan.
Spectroscopy Laboratory for Functional π-Electronic Systems and Department of Chemistry, Yonsei University, Seoul, 120-749, Korea.
Angew Chem Int Ed Engl. 2017 Nov 13;56(46):14688-14693. doi: 10.1002/anie.201708429. Epub 2017 Oct 10.
Oxidative fusion reactions of ortho-phenylene-bridged cyclic hexapyrroles and hexathiophenes furnished novel closed helicenes in a selective manner. X-Ray diffraction analysis unambiguously revealed the structures to be a closed pentaaza[9]helicene, the longest azahelicene reported so far, and an unexpected double-helical structure of hexathia[9]/[5]helicene, whose formation was assumed to result from multiple oxidative fusion along with a 1,2-aryl shift. The pentaaza[9]helicene exhibited well-defined emission with high fluorescence quantum yield (Φ =0.31) among the known [9]helicenes. Chiral resolution of the racemic pentaaza[9]helicene and hexathia[9]/[5]helicene were achieved by chiral-phase HPLC and the enantiomers were characterized by circular dichroism spectra and DFT calculations.
邻苯撑桥环六吡咯和六噻吩的氧化融合反应以选择性的方式提供了新型的闭合螺旋。X 射线衍射分析明确揭示了这些结构为一个闭合的五氮杂[9]螺旋，这是迄今为止报道的最长的氮杂螺旋，以及一个意想不到的六硫杂[9]/[5]螺旋的双重螺旋结构，其形成被认为是由于多次氧化融合以及 1,2-芳基迁移。在已知的[9]螺旋中，五氮杂[9]螺旋表现出具有高荧光量子产率（Φ=0.31）的明确发射。通过手性相高效液相色谱法实现了外消旋五氮杂[9]螺旋和六硫杂[9]/[5]螺旋的对映体拆分，并用圆二色光谱和 DFT 计算对其对映体进行了表征。
