Anthracene-incorporated cyanostilbene based donor-acceptor systems: intramolecular charge transfer and aggregation induced emission

• Published in: New journal of chemistry 2023-07, Vol.47 (29), p.1381-13819
• Main Authors: Femina, Cherumannil, Shanthil, M, Sajith, Pookkottu K, Thomas, Reji
• Format: Article
• Language: English
• Subjects: Anthracene; Charge transfer; Comparative studies; Emission analysis; Ethyl acetate; Optoelectronics; Red shift; Single crystals; Solid state
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/d3nj00478c

Cyanostilbene systems are highly attractive due to their fascinating fluorescence properties in the solid state. Herein, we report the synthesis and photophysical properties of highly emissive donor-acceptor systems based on anthracene and cyanostilbene, carrying hexyl ( CSB-1 ) and dodecyl ( CSB-2 ) chains. The molecules showed strong emission in the solution state attributed to the intramolecular charge transfer (ICT). The ICT band in these molecules showed a solvatochromic redshift with an increase in the dielectric constant of the solvents. The study explored the solid state emission properties of CSB-1 and compared them with that of dodecyloxy derivative CSB-2 . Both CSB-1 and CSB-2 showed comparable emission in the solid state attributed to slipped molecular arrangement. Interestingly, the molecule CSB-1 showed a stimuli responsive dual mode luminescence switching under applied stress and ethyl acetate vapours. Owing to the rigid molecular packing, CSB-1 showed a higher quantum yield ( F = 0.43) in the solid state in comparison to polycrystalline CSB-2 ( F = 0.37). The analysis of the single crystal structural data of CSB-1 has shown that the molecules possess a twisted geometry and the adjacent molecular pair comprises J-aggregates, with arrangement along the molecular long axis. A comparative study of powder X-ray diffractograms showed that both CSB-1 and CSB-2 adopt similar molecular packing with different interplanar distances along the molecular long axis. Furthermore, this study substantiates the experimental results with TD-DFT calculations. The present study provides a detailed structure-property correlation of two novel compounds with the potential for various optoelectronic applications. Anthracene-cyanostilbene based donor-acceptor systems with intramolecular charge transfer and aggregation induced emission properties are reported.