The anthrazolines are a class of diazaacenes that are constituted of three fused rings.These small molecules have great potential as thermally stable semiconductors for organic electronics, with high electron affinity and are promising electron-transport materials for OLED. These compounds are generally synthesized from complex starting materials. Thus, here this method provides easy access for symmetrical and asymmetrical anthrazolines. Analyzing the data in Figure 1, it can be seen that NbCl5 successfully promotes the synthesis of nitroquinoline (4) and anthrazoline derivatives (7a-b) with good yields in Multicomponent Reaction (MCR). In Figure 2 we see UV-Vis absorption measurements of compounds 7a-b in acid (acetic acid in ethanol, pH ~ 1), basic (ammonium hydroxide in ethanol, pH ~ 12) and neutral (ethanol) medium. We observe that in basic and neutral medium, the molecules 7a and 7b exhibit the same behavior (λmax 395 nm for 7a and 388 nm for 7b), while in acid medium a new band appears (490 nm for 7a and 486 nm for 7b). When irradiated with UV-Vis 365 nm light in basic and neutral medium it is observed a greenish color, while a red color is witnessed in acid medium for compound 7a. For 7b, the emission in basic medium is observed the intense yellow color, in neutral and acid medium it observes weak yellow color. In the solid-state 7a does not show fluorescence, while 7b shows intense yellow fluorescence (inset Fig 2). These compounds emits blue, red, green or yellow depending on the substituents or the solvent in which it is dissolved. In conclusion, we successfully synthesized two new anthrazoline derivatives which have potential for many applications, the reason why motivates us to continue the investigation of the properties of these compounds.

Synthesis and effect of acid-base on the ultraviolet−visible absorption properties of new anthrazoline derivatives

254th National Meeting (2017)

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