Spectroscopic and computational studies of the solid state photophysical properties of a biscoumarin dye

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Molecular and biomolecular spectroscopy, 2022-02, Vol.266, p.120466, Article 120466
• Main Authors: Elleuch, Slim, Ammar, Houcine, Abid, Younes
• Format: Article
• Language: English
• Subjects: Biscoumarin; DFT/TDDFT; ICT; Solid state photoluminescence; Thermal quenching; UV–Visible Absorption
• ISSN: 1386-1425
• DOI: 10.1016/j.saa.2021.120466

[Display omitted] •The 3,3'-paraphenyl bis[6,8-dimethoxy-2H-chromen-2-one] biscoumarin is synthesized and examined at the solid state level.•IR and Raman experimental techniques and DFT theoretical calculations are used.•Absorption features are related to ππ* and ICT electronic transitions.•Emission observed in the blue-green region at 506 nm is due to charge transfer.•Two thermal quenching regimes at low and high temperature were revealed. The solid state photophysical properties of the 3,3′-paraphenyl bis[6,8-dimethoxy-2H-chromen-2-one] symmetrical biscoumarin material were investigated by optical spectroscopy techniques and by theoretical calculations. Vibrational analysis using IR absorption and Raman scattering techniques carried out together with DFT theoretical calculations have confirmed the structure of this biscoumarin. The geometry optimization using different functionals reveal a nonplanar equilibrium structure with a dihedral between the phenyl and the pyran rings of about 142°. The UV–Visible absorption measurements and the TDDFT simulation show that this biscoumarin is characterized by a bicomponent feature resulting from ππ* electronic transitions and Intramolecular Charge Transfer (ICT). Solid state photoluminescence showed a bright blue-green emission at 506 nm with a large stokes shift estimated at 146 nm, and the temperature dependence study of this emission reveals two thermal evolution regimes. Finally, these good optical properties, as well as the stability of the emission, make this biscoumarin dye of potential interest for optoelectronic applications.