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Leitonas K, Vigante B, Volyniuk D, Bucinskas A, Dimitrijevs P, Lapcinska S, Arsenyan P, Grazulevicius JV. Aromatic systems with two and three pyridine-2,6-dicarbazolyl-3,5-dicarbonitrile fragments as electron-transporting organic semiconductors exhibiting long-lived emissions. Beilstein J Org Chem 2023; 19:1867-1880. [PMID: 38116244 PMCID: PMC10729123 DOI: 10.3762/bjoc.19.139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 10/18/2023] [Indexed: 12/21/2023] Open
Abstract
The pyridine-3,5-dicarbonitrile moiety has gained significant attention in the field of materials chemistry, particularly in the development of heavy-metal-free pure organic light-emitting diodes (OLEDs). Extensive research on organic compounds exhibiting thermally activated delayed fluorescence (TADF) has led to numerous patents and research articles. This study focuses on the synthesis and investigation of the semiconducting properties of polyaromatic π-systems containing two and three fragments of pyridine-2,6-dicarbazolyl-3,5-dicarbonitrile. The compounds are synthesized by Sonogashira coupling reactions and characterized by steady-state and time-resolved luminescence spectroscopy. The compounds show efficient intramolecular charge transfer (ICT) from the donor to the acceptor. The photoluminescence (PL) spectra of the solutions of the compounds showed non-structured emission peaks in the visible region, which are attributed to ICT emission. The PL intensities of the solutions of the compounds are enhanced after deoxygenation, which is indicative of TADF. The photoluminescence quantum yields and TADF properties of the compounds are sensitive to the medium. Cyclic voltammetry measurements indicate good hole-blocking and electron-injecting properties due to their high ionization potentials. Photoelectron spectroscopy and time-of-flight measurements reveal good electron-transporting properties for one of the compounds. In general, polyaromatic π-systems with pyridine-3,5-dicarbonitrile fragments demonstrate promising potential for use in organic electronic devices, such as OLEDs.
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Affiliation(s)
- Karolis Leitonas
- Department of Polymer Chemistry and Technology, Kaunas University of Technology, Radvilenu pl. 19, LT-50254, Kaunas, Lithuania
| | - Brigita Vigante
- Latvian Institute of Organic Synthesis, Aizkraukles 21, LV-1006, Riga, Latvia
| | - Dmytro Volyniuk
- Department of Polymer Chemistry and Technology, Kaunas University of Technology, Radvilenu pl. 19, LT-50254, Kaunas, Lithuania
| | - Audrius Bucinskas
- Department of Polymer Chemistry and Technology, Kaunas University of Technology, Radvilenu pl. 19, LT-50254, Kaunas, Lithuania
| | - Pavels Dimitrijevs
- Latvian Institute of Organic Synthesis, Aizkraukles 21, LV-1006, Riga, Latvia
| | - Sindija Lapcinska
- Latvian Institute of Organic Synthesis, Aizkraukles 21, LV-1006, Riga, Latvia
| | - Pavel Arsenyan
- Latvian Institute of Organic Synthesis, Aizkraukles 21, LV-1006, Riga, Latvia
| | - Juozas Vidas Grazulevicius
- Department of Polymer Chemistry and Technology, Kaunas University of Technology, Radvilenu pl. 19, LT-50254, Kaunas, Lithuania
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