Facile synthesis and self-assembly of diazafluorenone-based p-n (donor-acceptor) organic semiconductors

A mild and effective method to prepare 2,7-dibromo-4,5-diazafluoren-9-one (3) has been described involving tandem oxidation and rearrangement reactions. Diazafluorenone-based donor–acceptor (p–n) molecules via stille coupling reactions exhibit solvent-dependent fluorescence and excellent self-assembly behaviors at the solid–liquid interface according to the characterization of scanning tunneling microscopy (STM).