Synthesis of 5,12-Diazapentacenes and Their Properties

An efficient synthesis via a precursor route to a new class of linear dialkyldiaminoazapentacenes is reported. The synthetic route involves the coupling of 4 substituted aniline derivatives to 2,5 dibromoterephthalonitrile via Buchwald Hartwig amination followed by an acid mediated cyclization to furnish the diazapentacenes. These reactions occur under short reaction times (<2 h.) and high yields (77–99%) and do not require column chromatography for purification. The electrochemical and optical properties of the diazapentacenes were evaluated, and the values indicate that these molecules are promising n-type materials for organic electronic devices. The photostability of these molecules was significantly greater than unsubstituted acenes. Their method of degradation via endoperoxide generation was confirmed by X-ray crystallography and mass spectrometry.