Synthesis of 5-azatetracene and comparison of its optical and electrochemical properties with tetracene

• Main Authors: Ghosh, Animesh, Budanovic, Maja, Li, Tianjiao, Liang, Caihong, Klein, Maciej, Soci, Cesare, Webster, Richard David, Gurzadyan, Gagik G., Grimsdale, Andrew C.
• Other Authors: School of Materials Science and Engineering
• Format: Article
• Language: English
• Published: 2021
• Subjects: Science::Chemistry::Organic chemistry; Cyclic Voltammetry; Field-Effect Transistor; Friedlander Condensation; Nitrogen Heterocycles; Photoluminescence Spectroscopy; Time Resolved Measurements
• Online Access: https://hdl.handle.net/10356/153443
• Institution: Nanyang Technological University

A four-step route for the synthesis of 5-azatetraceene (benzo[b]acridine) has been developed, employing a base-catalysed Friedlander condensation reaction between 3-amino-2-napthaldehyde and cyclohexanone as the key step followed by dehydrogenation of the intermediate. The optical and electrochemical properties of the 5-azatetracene were investigated by UV-vis and photoluminescence spectroscopy, and by cyclic voltammetry and compared with those of tetracene. It is found that 5-azatetracene shows broader absorption in the visible region than tetracene, exhibits a higher luminescence quantum efficiency, and possesses a lower-lying LUMO level and smaller HOMO-LUMO band gap. Time-resolved PL spectroscopy was used to elucidate the reasons for the more efficient luminescence of 5-azatetracene. Field-effect transistor measurements revealed the ambipolar nature of charge transport in 5-azatetracene.