Mishra Shantanu, Fatayer Shadi, Fernández Saleta, Kaiser Katharina, Peña Diego, Gross Leo
IBM Research-Zurich, 8803 Rüschlikon, Switzerland.
Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS) and Departamento de Química Orgánica, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
ACS Nano. 2022 Feb 22;16(2):3264-3271. doi: 10.1021/acsnano.1c11157. Epub 2022 Feb 8.
We report the on-surface synthesis of a nonbenzenoid triradical through dehydrogenation of truxene (CH) on coinage metal and insulator surfaces. Voltage pulses applied the tip of a combined scanning tunneling microscope/atomic force microscope were used to cleave individual C-H bonds in truxene. The resultant final product truxene-5,10,15-triyl () was characterized at the single-molecule scale using a combination of atomic force microscopy, scanning tunneling microscopy, and scanning tunneling spectroscopy. Our analyses show that retains its open-shell quartet ground state, predicted by density functional theory, on a two monolayer-thick NaCl layer on a Cu(111) surface. We image the frontier orbital densities of and confirm that they correspond to spin-split singly occupied molecular orbitals. Through our synthetic strategy, we also isolate two reactive intermediates toward the synthesis of , derivatives of fluorenyl radical and indeno[1,2-]fluorene, with predicted open-shell doublet and triplet ground states, respectively. Our results should have bearings on the synthesis of nonbenzenoid high-spin polycyclic frameworks with magnetism beyond Lieb's theorem.
我们报道了通过在硬币金属和绝缘体表面上对均三苯（CH）进行脱氢反应，在表面上合成一种非苯型三自由基。利用组合式扫描隧道显微镜/原子力显微镜（STM/AFM）尖端施加的电压脉冲来裂解均三苯中的单个C-H键。使用原子力显微镜、扫描隧道显微镜和扫描隧道谱学相结合的方法，在单分子尺度上对最终产物均三苯-5,10,15-三基（）进行了表征。我们的分析表明，在Cu(111)表面上的两层氯化钠厚层上，其保留了密度泛函理论预测的开壳四重态基态。我们对的前沿轨道密度进行成像，并确认它们对应于自旋分裂的单占据分子轨道。通过我们的合成策略，我们还分离出了两种在合成过程中的反应中间体，即芴基自由基衍生物和茚并[1,2-]芴，它们分别具有预测的开壳二重态和三重态基态。我们的结果应该对具有超越李伯定理磁性的非苯型高自旋多环框架的合成具有指导意义。
