Lehnherr Dan, Chen Chen, Pedramrazi Zahra, DeBlase Catherine R, Alzola Joaquin M, Keresztes Ivan, Lobkovsky Emil B, Crommie Michael F, Dichtel William R
Department of Chemistry and Chemical Biology , Baker Laboratory , Cornell University , Ithaca , New York 14853-1301 , USA . Email:
Department of Physics , University of California at Berkeley , Berkeley , California 94720 , USA . Email:
Chem Sci. 2016 Oct 1;7(10):6357-6364. doi: 10.1039/c6sc02520j. Epub 2016 Jul 8.
A Cu-catalyzed benzannulation reaction transforms (arylene ethynylene) oligomers into -arylenes. This approach circumvents iterative Suzuki cross-coupling reactions previously used to assemble hindered -arylene backbones. These derivatives form helical folded structures in the solid-state and in solution, as demonstrated by X-ray crystallography and solution-state NMR analysis. DFT calculations of misfolded conformations are correlated with variable-temperature H and EXSY NMR to reveal that folding is cooperative and more favorable in halide-substituted naphthalenes. Helical -arylene foldamers with specific aromatic sequences organize functional π-electron systems into arrangements ideal for ambipolar charge transport and show preliminary promise for the surface-mediated synthesis of structurally defined graphene nanoribbons.
铜催化的苯并环化反应将（亚芳基乙炔）低聚物转化为亚芳基。这种方法避免了先前用于组装受阻亚芳基主链的迭代铃木交叉偶联反应。如X射线晶体学和溶液态核磁共振分析所示，这些衍生物在固态和溶液中形成螺旋折叠结构。对错误折叠构象的密度泛函理论计算与变温氢核磁共振和交换光谱核磁共振相关联，以揭示折叠是协同的，并且在卤化物取代的萘中更有利。具有特定芳香序列的螺旋亚芳基折叠体将功能性π电子系统组织成适合双极性电荷传输的理想排列，并显示出在表面介导合成结构明确的石墨烯纳米带方面的初步前景。
