Synthesis, optical and electrochemical properties of isomeric dibenzophenanthroline derivatives

• Main Authors: Ghosh, Animesh, Li, Tianjiao, Ni, Wenjun, Wu, Tong, Liang, Caihong, Budanovic, Maja, Morris, Samuel Alexander, Klein, Maciej, 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; Friedlander Condensation; Heteroacenes; Organic Semiconductor; Photoluminescence
• Online Access: https://hdl.handle.net/10356/153444
• Institution: Nanyang Technological University

Acid catalysed Friedländer cyclization of 2-aminobenzophenones with 1,2-, 1,3-, and 1,4-cyclohexadiones, followed by aromatization, has been used to prepare dibenzophenanthrolines (DBPs) containing 1,10-, 1,7- and 4,7-phenanthroline units, whose optoelectronic properties have been compared. The LUMO energies for all isomers were similar but the 4,7-isomers possessed significantly higher HOMOs than the other isomers, resulting in them having smaller HOMO-LUMO energy gaps. Compared with 1,10-DBP isomers, the emission of 1,7-DBPs is strongly quenched due to efficient charge transfer. The 4,7-DBP isomers show strongly enhanced photoluminescence due to excimer formation but appear to be less photostable due to their higher HOMO levels. Bis(phenylethynyl)-substituted derivatives demonstrated improved solubility and stronger luminescence properties than their unsubstituted analogues.