Matsuo Yusuke, Gon Masayuki, Tanaka Kazuo, Seki Shu, Tanaka Takayuki
Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.
Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan.
J Am Chem Soc. 2024 Jun 26;146(25):17428-17437. doi: 10.1021/jacs.4c05156. Epub 2024 Jun 12.
Synthetic challenges toward anomalous structures and electronic states often involve handling problems such as insolubility in common organic solvents and oxidative degradation under aerobic conditions. We designed benzo-annulated aza[]helicenes, which benefit from both the suppressed elevation of highest occupied molecular orbital (HOMO) energies and high solubility due to hydrogen bonding with solvent molecules to overcome these challenges. This strategy enabled the synthesis of six new aza[]helicenes (s) of different lengths ( = 9-19) from acyclic precursors via one-pot intramolecular oxidative fusion reactions. The structures of all of the synthesized aza[]helicenes were determined by X-ray diffraction (XRD) analysis, and their electrochemical potentials were measured by cyclic voltammetry. Among the synthesized aza[]helicenes, and are the first heterohelicenes with a triple-layered helix. The noncovalent interaction (NCI) plots confirm the existence of an effective π-π interaction between the layers. The absorption and fluorescence spectra red-shifted as the helical lengths increased, without any distinct saturation points. The optical resolutions of -butylated , , , and were accomplished, and their circular dichroism (CD) and circularly polarized luminescence (CPL) were measured. Thus, the structural, (chir)optical, and electrochemical properties of the aza[]helicenes were comprehensively analyzed.
合成具有异常结构和电子态面临的挑战通常涉及处理一些问题，如在常见有机溶剂中不溶以及在有氧条件下发生氧化降解。我们设计了苯并稠合氮杂[ ]螺旋烯，它既受益于最高占据分子轨道（HOMO）能量升高的抑制，又因与溶剂分子形成氢键而具有高溶解性，从而克服了这些挑战。该策略通过一锅法分子内氧化融合反应，从无环前体合成了六种不同长度（ = 9 - 19）的新型氮杂[ ]螺旋烯（s）。所有合成的氮杂[ ]螺旋烯的结构通过X射线衍射（XRD）分析确定，其电化学电位通过循环伏安法测量。在合成的氮杂[ ]螺旋烯中， 和 是首批具有三层螺旋的杂螺旋烯。非共价相互作用（NCI）图证实了层间存在有效的π - π相互作用。随着螺旋长度增加，吸收光谱和荧光光谱发生红移，且没有任何明显的饱和点。完成了 - 丁基化的 、 、 和 的光学拆分，并测量了它们的圆二色性（CD）和圆偏振发光（CPL）。因此，对氮杂[ ]螺旋烯的结构、（手性）光学和电化学性质进行了全面分析。
