基于非凯库勒式间醌二甲烷的氮杂并四苯双自由基在红外光谱区域具有大的双光子截面
Azaacene Diradicals Based on Non-Kekulé Meta-Quinodimethane with Large Two-Photon Cross-Sections in the Infrared Spectral Region.
作者信息
Fuchs Kathleen, Oberhof Nils, Sauter Gabriel, Pollien Audrey, Brödner Kerstin, Rominger Frank, Freudenberg Jan, Dreuw Andreas, Tegeder Petra, Bunz Uwe H F
机构信息
Organisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany.
Interdisciplinary Center for Scientific Computing, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 205, 69120, Heidelberg, Germany.
出版信息
Angew Chem Int Ed Engl. 2024 Nov 25;63(48):e202406384. doi: 10.1002/anie.202406384. Epub 2024 Oct 25.
Non-Kekulé quinoidal azaacences m-A (1 a,b) were synthesized and compared to their para- and ortho-quinodimethane analogues. m-A display high diradical characters (1 b: y = 0.88) due to their meta-quinodimethane (m-QDM) topology. Electron paramagnetic, nuclear magnetic resonance spectroscopies and supraquantum interference device measurements in combination with quantum-chemical calculations revealed singlet ground states for m-A with singlet-triplet gaps ΔE (0.13-0.25 kcal mol) and thermally populated triplet states. These non-Kekulé structures are over all void of zwitterionic character and possess record high two-photon absorption cross sections over a broad spectral range in the near-infrared.
合成了非凯库勒醌型氮杂并苯m-A（1 a,b），并将其与对醌二甲烷和邻醌二甲烷类似物进行了比较。由于其间醌二甲烷（m-QDM）拓扑结构，m-A表现出较高的双自由基特征（1 b：y = 0.88）。电子顺磁共振、核磁共振光谱以及超量子干涉器件测量与量子化学计算相结合，揭示了m-A的单重态基态，其单重态-三重态能隙ΔE为（0.13 - 0.25 kcal mol），且三重态为热激发态。这些非凯库勒结构总体上没有两性离子特征，并且在近红外的宽光谱范围内具有创纪录的高二光子吸收截面。
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