Abstract
Over the past three decades, polycyclic aromatic hydrocarbons have gained widespread use in materials chemistry, organic electronics, and the design of chemosensors and molecular probes for biomedical applications. In particular, 1,4-diazatriphenylene, also known as dibenzo[f,h]quinoxaline, along with its heteroannelated analogs, is regarded as a promising scaffold for developing functional charge-transport and light-emitting materials. The most common method for constructing the 1,4-diazatriphenylene skeleton is through condensation reactions (Route 1). Another less common synthetic approach involves intramolecular cyclizations of 2,3-di(het)aryl-substituted pyrazine derivatives using oxidative photocyclization (Mallory reaction) or intramolecular cyclodehydrogenation with chemical oxidants under acidic conditions (Scholl reaction) (Route 2). This report will particularly focus on the use of the intramolecular nucleophilic aromatic hydrogen substitution reaction (SNH-reaction) involving 2-bis(het)aryl-substituted 1,4-diazine derivatives (Route 3). In addition, data on the photophysical and electrochemical properties of the resulting products, as well as their potential applications as organic semiconductor materials, will be discussed.