Benz[X]azole derivatives are interesting compounds due to their diverse biological activities¹ and interesting optical properties.²  The benzothiazole, benzimidazole, and benzoxazole heterocycles are heteroaromatic electron deficient moieties that act as both acceptor groups and pi-conjugated spacers with auxiliary electron withdrawing ability.^2,3 Moreover, benzimidazole derivatives offers the possibility of substitution on the nitrogen atom for further tuning of their optical and electronic properties.

Recently we have reported the synthesis and evaluation of the electronic, thermal and optical properties of a large number of series of benz[X]azole derivatives functionalized with different π-spacers having in mind their application as optical chemosensors, nonlinear optical and photochromic materials, and emissive organic components for OLEDs.²

In continuation of the work developed by our research group, we report in this communication the synthesis, the characterization and the evaluation of the optical properties of four novel 1-(4-thiophene-2-yl)phenyl)-1H-pyrrole derivatives functionalized with different benz[X]azole moieties (benzothiazole, benzimidazole, and benzoxazole). The results showed that the optical properties could be readily tuned by changing the electronic nature of the azole ring, or even by the introduction of a strong acceptor group.

Acknowledgements: Thank are due to Fundação para a Ciência e Tecnologia (Portugal) and FEDER-COMPETE for financial support through Centro de Química (UID/QUI/00686/2013 and UID/ QUI/0686/2016), and a PhD grant to S. S. M. Fernandes (SFRH/BD/87786/2012). The NMR spectrometer Bruker Avance III 400 is part of the National NMR Network and was purchased within the framework of the National Program for Scientific Re-equipment, contract REDE/1517/RMN/2005 with funds from POCI 2010 (FEDER) and FCT.

 References

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