Substituted Tetraaza- and Hexaazahexacenes and their N,N-Dihydro Derivatives: Syntheses, Properties, and Structures

The palladium-catalyzed coupling of a substituted o-diaminoanthracene and a substituted o-diaminophenazine to substituted 2,3-dichloroquinoxalines furnishes 10 differently substituted N,N-dihydrotetraaza- or -hexaazahexacenes with the quinoxaline group of the azaacenes carrying fluorine, chlorine, or nitro groups. The N,N-dihydrotetraazahexacenes with hydrogen, chlorine, and fluorine subtituentsare oxidized to azaacenes, whereas only the parent N,N-dihydrohexaazahexacenes, with hydrogen substituents, are oxidized by MnO2. The resultant azaacenes are characterized by their optical and spectroscopic data. In addition, single-crystal X-ray structures have been obtained for the parent tetraazahexacenes and their difluoro-substituted derivatives. The di- and tetrachloro derivatives of the N,N-dihydrohexaazahexacene have also been structurally characterized.