Luminescent quinolines aroused great interest in the fields of organic electronic. We know that substituents have a key effect on the properties, thus, when combined with organic p-conjugated heterocyclic compounds that contain a sulfur atom (thiophene) exhibit an extensive potential for optical, electrical and photoelectric applications. In this paper we report the photophysical investigation about the phenomenon of color change with solvent polarity (solvatochromism) that is a relevant tool to explain the internal properties of these four quinoline derivatives synthesized containing thiophene units. In the UV-Vis absorption we can see the tendency is to increase the dielectric constant, shifting the λmax batochromically. In general, we observe that in hexane, all the compounds presented the lowest values, but we highlight DMSO and DMF that shifted bathochromically all compounds (Fig. 1). The Solvatochromism shown by emission of compounds under UV-lamp (365 nm) is seen in Figure 2. Compound 4a with nitro group and one thiophene unit does not emit in any solvent, but the compounds 4b, 5a and 5b show emission in all solvents. Here, we highlight the compound 4b, with nitro group and two thiophene units, that show a wide variety of colors (green, yellow, orange and blue). All results obtained in this study are important for quantum chemistry practical applications in the design of functional dyes. In conclusion, there is the possibility of modulating the emission wavelength of such compounds by introducing functional groups and/or extending the conjugation around the core.

Photophysical investigations of the solvent effect on the properties of emitting thiophene-quinoline derivatives

254th National Meeting (2017)

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