Zigzag‐Edged Polycyclic Aromatic Hydrocarbons from Benzo[m]tetraphene Precursors

Abstract

AbstractA series of zigzag‐edged polycyclic aromatic hydrocarbons (PAHs) (Z1‐Z3) were synthesized from 2,12‐dibromo‐7,14‐diphenyl‐benzo[m]tetraphene (9) as a versatile building block. Their structures were unambiguously confirmed by laser desorption/ionization time‐of‐flight mass spectrometry, 1H NMR, Raman, and Fourier‐transformed infrared (FTIR) spectroscopies as well as scanning tunneling microscopy. The fingerprint vibrational modes were elucidated with theoretical support. The edge‐ and size‐dependent optical properties were characterized by UV‐Vis absorption and fluorescence spectroscopy and DFT calculations. Moreover, ultrafast transient absorption spectroscopy revealed distinct modulation of the photophysical properties upon π‐extension from Z1 to Z2, the latter having a gulf edge.